diff --git a/codex-rs/app-server/tests/suite/v2/turn_start.rs b/codex-rs/app-server/tests/suite/v2/turn_start.rs
index e5c5c5adbb..586fcef87f 100644
--- a/codex-rs/app-server/tests/suite/v2/turn_start.rs
+++ b/codex-rs/app-server/tests/suite/v2/turn_start.rs
@@ -54,6 +54,7 @@ use codex_app_server_protocol::UserInput as V2UserInput;
 use codex_app_server_protocol::WarningNotification;
 use codex_config::config_toml::ConfigToml;
 use codex_core::personality_migration::PERSONALITY_MIGRATION_FILENAME;
+use codex_core::test_support::all_model_presets;
 use codex_features::FEATURES;
 use codex_features::Feature;
 use codex_protocol::config_types::CollaborationMode;
@@ -375,13 +376,19 @@ async fn turn_start_sends_service_tier_id_to_model_request() -> Result<()> {
         "never",
         &BTreeMap::default(),
     )?;
+    write_models_cache(codex_home.path())?;
+    let service_tier_model = all_model_presets()
+        .iter()
+        .find(|preset| preset.show_in_picker && !preset.service_tiers.is_empty())
+        .expect("bundled model catalog should include a picker model with service tiers");
+    let service_tier_id = service_tier_model.service_tiers[0].id.clone();
 
     let mut mcp = McpProcess::new(codex_home.path()).await?;
     timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
 
     let thread_req = mcp
         .send_thread_start_request(ThreadStartParams {
-            model: Some("mock-model".to_string()),
+            model: Some(service_tier_model.id.clone()),
             ..Default::default()
         })
         .await?;
@@ -392,7 +399,6 @@ async fn turn_start_sends_service_tier_id_to_model_request() -> Result<()> {
     .await??;
     let ThreadStartResponse { thread, .. } = to_response::<ThreadStartResponse>(thread_resp)?;
 
-    let service_tier_id = "experimental-tier-id".to_string();
     let turn_req = mcp
         .send_turn_start_request(TurnStartParams {
             thread_id: thread.id,
diff --git a/codex-rs/core/src/client.rs b/codex-rs/core/src/client.rs
index 39e6e85e20..53c1eb0d7e 100644
--- a/codex-rs/core/src/client.rs
+++ b/codex-rs/core/src/client.rs
@@ -711,6 +711,8 @@ impl ModelClient {
             prompt.output_schema_strict,
         );
         let prompt_cache_key = Some(self.state.thread_id.to_string());
+        let service_tier =
+            service_tier.filter(|service_tier| model_info.supports_service_tier(service_tier));
         let request = ResponsesApiRequest {
             model: model_info.slug.clone(),
             instructions: instructions.clone(),
diff --git a/codex-rs/core/src/config/edit.rs b/codex-rs/core/src/config/edit.rs
index 1362103364..02ec9dc898 100644
--- a/codex-rs/core/src/config/edit.rs
+++ b/codex-rs/core/src/config/edit.rs
@@ -7,7 +7,6 @@ use codex_config::types::SessionPickerViewMode;
 use codex_config::types::ToolSuggestDisabledTool;
 use codex_features::FEATURES;
 use codex_protocol::config_types::Personality;
-use codex_protocol::config_types::ServiceTier;
 use codex_protocol::config_types::TrustLevel;
 use codex_protocol::openai_models::ReasoningEffort;
 use std::collections::BTreeMap;
@@ -33,7 +32,7 @@ pub enum ConfigEdit {
         effort: Option<ReasoningEffort>,
     },
     /// Update the service tier preference for future turns.
-    SetServiceTier { service_tier: Option<ServiceTier> },
+    SetServiceTier { service_tier: Option<String> },
     /// Update the active (or default) model personality.
     SetModelPersonality { personality: Option<Personality> },
     /// Toggle the acknowledgement flag under `[notice]`.
@@ -536,7 +535,9 @@ impl ConfigDocument {
             }),
             ConfigEdit::SetServiceTier { service_tier } => Ok(self.write_profile_value(
                 &["service_tier"],
-                service_tier.map(|service_tier| value(service_tier.to_string())),
+                service_tier
+                    .as_ref()
+                    .map(|service_tier| value(service_tier.clone())),
             )),
             ConfigEdit::SetModelPersonality { personality } => Ok(self.write_profile_value(
                 &["personality"],
@@ -1114,7 +1115,7 @@ impl ConfigEditsBuilder {
         self
     }
 
-    pub fn set_service_tier(mut self, service_tier: Option<ServiceTier>) -> Self {
+    pub fn set_service_tier(mut self, service_tier: Option<String>) -> Self {
         self.edits.push(ConfigEdit::SetServiceTier { service_tier });
         self
     }
diff --git a/codex-rs/core/src/session/turn_context.rs b/codex-rs/core/src/session/turn_context.rs
index d4fe30063f..5c8aad0225 100644
--- a/codex-rs/core/src/session/turn_context.rs
+++ b/codex-rs/core/src/session/turn_context.rs
@@ -521,6 +521,10 @@ impl Session {
             &per_turn_config.agent_roles,
         ));
 
+        let mut per_turn_config = per_turn_config;
+        per_turn_config.service_tier = per_turn_config
+            .service_tier
+            .filter(|service_tier| model_info.supports_service_tier(service_tier));
         let per_turn_config = Arc::new(per_turn_config);
         let turn_metadata_state = Arc::new(TurnMetadataState::new(
             session_id.to_string(),
diff --git a/codex-rs/core/tests/suite/model_switching.rs b/codex-rs/core/tests/suite/model_switching.rs
index e962b06d41..21ab43f10d 100644
--- a/codex-rs/core/tests/suite/model_switching.rs
+++ b/codex-rs/core/tests/suite/model_switching.rs
@@ -9,6 +9,7 @@ use codex_protocol::models::PermissionProfile;
 use codex_protocol::openai_models::ConfigShellToolType;
 use codex_protocol::openai_models::InputModality;
 use codex_protocol::openai_models::ModelInfo;
+use codex_protocol::openai_models::ModelServiceTier;
 use codex_protocol::openai_models::ModelVisibility;
 use codex_protocol::openai_models::ModelsResponse;
 use codex_protocol::openai_models::ReasoningEffort;
@@ -320,9 +321,28 @@ async fn flex_service_tier_is_applied_to_http_turn() -> Result<()> {
     skip_if_no_network!(Ok(()));
 
     let server = start_mock_server().await;
+    let model_slug = "test-flex-model";
+    let mut flex_model = test_model_info(
+        model_slug,
+        model_slug,
+        "supports flex tier",
+        default_input_modalities(),
+    );
+    flex_model.service_tiers = vec![ModelServiceTier {
+        id: ServiceTier::Flex.request_value().to_string(),
+        name: "flex".to_string(),
+        description: "Flexible processing.".to_string(),
+    }];
     let resp_mock = mount_sse_once(&server, sse_completed("resp-1")).await;
 
-    let test = test_codex().build(&server).await?;
+    let mut builder = test_codex()
+        .with_model(model_slug)
+        .with_config(move |config| {
+            config.model_catalog = Some(ModelsResponse {
+                models: vec![flex_model],
+            });
+        });
+    let test = builder.build(&server).await?;
 
     test.submit_turn_with_service_tier("flex turn", Some(ServiceTier::Flex))
         .await?;
@@ -334,6 +354,39 @@ async fn flex_service_tier_is_applied_to_http_turn() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn unsupported_service_tier_is_omitted_from_http_turn() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let model_slug = "test-no-tier-model";
+    let model = test_model_info(
+        model_slug,
+        model_slug,
+        "no service tiers",
+        default_input_modalities(),
+    );
+    let resp_mock = mount_sse_once(&server, sse_completed("resp-1")).await;
+
+    let mut builder = test_codex()
+        .with_model(model_slug)
+        .with_config(move |config| {
+            config.model_catalog = Some(ModelsResponse {
+                models: vec![model],
+            });
+        });
+    let test = builder.build(&server).await?;
+
+    test.submit_turn_with_service_tier("fast turn", Some(ServiceTier::Fast))
+        .await?;
+
+    let request = resp_mock.single_request();
+    let body = request.body_json();
+    assert_eq!(body.get("service_tier"), None);
+
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn model_change_from_image_to_text_strips_prior_image_content() -> Result<()> {
     skip_if_no_network!(Ok(()));
diff --git a/codex-rs/model-provider/src/amazon_bedrock/catalog.rs b/codex-rs/model-provider/src/amazon_bedrock/catalog.rs
index 60fa17d368..153c2db2ef 100644
--- a/codex-rs/model-provider/src/amazon_bedrock/catalog.rs
+++ b/codex-rs/model-provider/src/amazon_bedrock/catalog.rs
@@ -1,14 +1,17 @@
 use codex_models_manager::model_info::BASE_INSTRUCTIONS;
 use codex_protocol::config_types::ReasoningSummary;
+use codex_protocol::config_types::ServiceTier;
 use codex_protocol::config_types::Verbosity;
 use codex_protocol::openai_models::ApplyPatchToolType;
 use codex_protocol::openai_models::ConfigShellToolType;
 use codex_protocol::openai_models::InputModality;
 use codex_protocol::openai_models::ModelInfo;
+use codex_protocol::openai_models::ModelServiceTier;
 use codex_protocol::openai_models::ModelVisibility;
 use codex_protocol::openai_models::ModelsResponse;
 use codex_protocol::openai_models::ReasoningEffort;
 use codex_protocol::openai_models::ReasoningEffortPreset;
+use codex_protocol::openai_models::SPEED_TIER_FAST;
 use codex_protocol::openai_models::TruncationPolicyConfig;
 use codex_protocol::openai_models::WebSearchToolType;
 
@@ -46,8 +49,12 @@ fn gpt_5_4_cmb_bedrock_model(priority: i32) -> ModelInfo {
         visibility: ModelVisibility::List,
         supported_in_api: true,
         priority,
-        additional_speed_tiers: vec!["fast".to_string()],
-        service_tiers: Vec::new(),
+        additional_speed_tiers: Vec::new(),
+        service_tiers: vec![ModelServiceTier {
+            id: ServiceTier::Fast.request_value().to_string(),
+            name: SPEED_TIER_FAST.to_string(),
+            description: "Fastest inference with increased plan usage".to_string(),
+        }],
         availability_nux: None,
         upgrade: None,
         base_instructions: BASE_INSTRUCTIONS.to_string(),
diff --git a/codex-rs/protocol/src/openai_models.rs b/codex-rs/protocol/src/openai_models.rs
index 70d241677c..96179440bd 100644
--- a/codex-rs/protocol/src/openai_models.rs
+++ b/codex-rs/protocol/src/openai_models.rs
@@ -17,6 +17,7 @@ use ts_rs::TS;
 
 use crate::config_types::Personality;
 use crate::config_types::ReasoningSummary;
+use crate::config_types::ServiceTier;
 use crate::config_types::Verbosity;
 
 const PERSONALITY_PLACEHOLDER: &str = "{{ personality }}";
@@ -479,13 +480,23 @@ impl ModelPreset {
     pub fn supports_fast_mode(&self) -> bool {
         self.service_tiers
             .iter()
-            .any(|tier| tier.id == SPEED_TIER_FAST)
+            .any(|tier| tier.id == ServiceTier::Fast.request_value())
             || self
                 .additional_speed_tiers
                 .iter()
                 .any(|tier| tier == SPEED_TIER_FAST)
     }
+}
 
+impl ModelInfo {
+    pub fn supports_service_tier(&self, service_tier: &str) -> bool {
+        self.service_tiers
+            .iter()
+            .any(|tier| tier.id == service_tier)
+    }
+}
+
+impl ModelPreset {
     /// Filter models based on authentication mode.
     ///
     /// In ChatGPT mode, all models are visible. Otherwise, only API-supported models are shown.
@@ -853,7 +864,7 @@ mod tests {
     fn model_preset_supports_fast_mode_from_service_tiers() {
         let preset = ModelPreset::from(ModelInfo {
             service_tiers: vec![ModelServiceTier {
-                id: SPEED_TIER_FAST.to_string(),
+                id: ServiceTier::Fast.request_value().to_string(),
                 name: "Fast".to_string(),
                 description: "Priority processing.".to_string(),
             }],
diff --git a/codex-rs/tui/src/app/event_dispatch.rs b/codex-rs/tui/src/app/event_dispatch.rs
index bfe8dc4b24..b2261f155a 100644
--- a/codex-rs/tui/src/app/event_dispatch.rs
+++ b/codex-rs/tui/src/app/event_dispatch.rs
@@ -1274,26 +1274,21 @@ impl App {
             AppEvent::PersistServiceTierSelection { service_tier } => {
                 self.refresh_status_line();
                 let profile = self.active_profile.as_deref();
-                self.config.service_tier =
-                    service_tier.map(|service_tier| service_tier.request_value().to_string());
+                self.config.service_tier = service_tier.clone();
                 let mut edits = ConfigEditsBuilder::new(&self.config.codex_home)
                     .with_profile(profile)
-                    .set_service_tier(service_tier);
+                    .set_service_tier(service_tier.clone());
                 if service_tier.is_none() {
                     self.config.notices.fast_default_opt_out = Some(true);
                     edits = edits.set_fast_default_opt_out(/*opted_out*/ true);
                 }
                 match edits.apply().await {
                     Ok(()) => {
-                        let status = if matches!(
-                            service_tier,
-                            Some(codex_protocol::config_types::ServiceTier::Fast)
-                        ) {
-                            "on"
+                        let mut message = if let Some(service_tier) = service_tier {
+                            format!("Service tier set to {service_tier}")
                         } else {
-                            "off"
+                            "Service tier cleared".to_string()
                         };
-                        let mut message = format!("Fast mode set to {status}");
                         if let Some(profile) = profile {
                             message.push_str(" for ");
                             message.push_str(profile);
@@ -1302,14 +1297,14 @@ impl App {
                         self.chat_widget.add_info_message(message, /*hint*/ None);
                     }
                     Err(err) => {
-                        tracing::error!(error = %err, "failed to persist fast mode selection");
+                        tracing::error!(error = %err, "failed to persist service tier selection");
                         if let Some(profile) = profile {
                             self.chat_widget.add_error_message(format!(
-                                "Failed to save Fast mode for profile `{profile}`: {err}"
+                                "Failed to save service tier for profile `{profile}`: {err}"
                             ));
                         } else {
                             self.chat_widget.add_error_message(format!(
-                                "Failed to save default Fast mode: {err}"
+                                "Failed to save default service tier: {err}"
                             ));
                         }
                     }
diff --git a/codex-rs/tui/src/app/session_lifecycle.rs b/codex-rs/tui/src/app/session_lifecycle.rs
index b114d08be9..05aba144c8 100644
--- a/codex-rs/tui/src/app/session_lifecycle.rs
+++ b/codex-rs/tui/src/app/session_lifecycle.rs
@@ -617,10 +617,7 @@ impl App {
 
     pub(super) fn fresh_session_config(&self) -> Config {
         let mut config = self.config.clone();
-        config.service_tier = self
-            .chat_widget
-            .configured_service_tier()
-            .map(|service_tier| service_tier.request_value().to_string());
+        config.service_tier = self.chat_widget.configured_service_tier();
         config.notices.fast_default_opt_out = self.chat_widget.fast_default_opt_out();
         config
     }
diff --git a/codex-rs/tui/src/app/tests.rs b/codex-rs/tui/src/app/tests.rs
index eacb6d5053..301808d155 100644
--- a/codex-rs/tui/src/app/tests.rs
+++ b/codex-rs/tui/src/app/tests.rs
@@ -3829,8 +3829,11 @@ async fn clear_ui_header_shows_fast_status_for_fast_capable_models() {
     set_fast_mode_test_catalog(&mut app.chat_widget);
     app.chat_widget
         .set_reasoning_effort(Some(ReasoningEffortConfig::XHigh));
-    app.chat_widget
-        .set_service_tier(Some(codex_protocol::config_types::ServiceTier::Fast));
+    app.chat_widget.set_service_tier(Some(
+        codex_protocol::config_types::ServiceTier::Fast
+            .request_value()
+            .to_string(),
+    ));
     set_chatgpt_auth(&mut app.chat_widget);
     set_fast_mode_test_catalog(&mut app.chat_widget);
 
@@ -4481,8 +4484,11 @@ fn active_turn_steer_race_extracts_actual_turn_id_from_mismatch() {
 #[tokio::test]
 async fn fresh_session_config_uses_current_service_tier() {
     let mut app = make_test_app().await;
-    app.chat_widget
-        .set_service_tier(Some(codex_protocol::config_types::ServiceTier::Fast));
+    app.chat_widget.set_service_tier(Some(
+        codex_protocol::config_types::ServiceTier::Fast
+            .request_value()
+            .to_string(),
+    ));
 
     let config = app.fresh_session_config();
 
diff --git a/codex-rs/tui/src/app/thread_session_state.rs b/codex-rs/tui/src/app/thread_session_state.rs
index 524d8f3c06..4f5f48cfc8 100644
--- a/codex-rs/tui/src/app/thread_session_state.rs
+++ b/codex-rs/tui/src/app/thread_session_state.rs
@@ -63,10 +63,7 @@ impl App {
                 thread_name: None,
                 model: self.chat_widget.current_model().to_string(),
                 model_provider_id: self.config.model_provider_id.clone(),
-                service_tier: self
-                    .chat_widget
-                    .current_service_tier()
-                    .map(|service_tier| service_tier.request_value().to_string()),
+                service_tier: self.chat_widget.current_service_tier().map(str::to_string),
                 approval_policy: AskForApproval::from(
                     self.config.permissions.approval_policy.value(),
                 ),
diff --git a/codex-rs/tui/src/app_event.rs b/codex-rs/tui/src/app_event.rs
index 4ee405f495..b72e909293 100644
--- a/codex-rs/tui/src/app_event.rs
+++ b/codex-rs/tui/src/app_event.rs
@@ -43,7 +43,6 @@ use codex_features::Feature;
 use codex_plugin::PluginCapabilitySummary;
 use codex_protocol::config_types::CollaborationModeMask;
 use codex_protocol::config_types::Personality;
-use codex_protocol::config_types::ServiceTier;
 use codex_protocol::models::PermissionProfile;
 use codex_protocol::openai_models::ReasoningEffort;
 use codex_realtime_webrtc::RealtimeWebrtcEvent;
@@ -569,7 +568,7 @@ pub(crate) enum AppEvent {
 
     /// Persist the selected service tier to the appropriate config.
     PersistServiceTierSelection {
-        service_tier: Option<ServiceTier>,
+        service_tier: Option<String>,
     },
 
     /// Open the device picker for a realtime microphone or speaker.
diff --git a/codex-rs/tui/src/bottom_pane/chat_composer.rs b/codex-rs/tui/src/bottom_pane/chat_composer.rs
index e7526203bc..2bd553ba6b 100644
--- a/codex-rs/tui/src/bottom_pane/chat_composer.rs
+++ b/codex-rs/tui/src/bottom_pane/chat_composer.rs
@@ -192,8 +192,11 @@ use super::paste_burst::CharDecision;
 use super::paste_burst::PasteBurst;
 use super::skill_popup::MentionItem;
 use super::skill_popup::SkillPopup;
-use super::slash_commands;
 use super::slash_commands::BuiltinCommandFlags;
+use super::slash_commands::ServiceTierCommand;
+use super::slash_commands::SlashCommandItem;
+use super::slash_commands::find_slash_command;
+use super::slash_commands::has_slash_command_prefix;
 use crate::bottom_pane::paste_burst::FlushResult;
 use crate::bottom_pane::prompt_args::parse_slash_name;
 use crate::key_hint::KeyBindingListExt;
@@ -276,6 +279,8 @@ pub enum InputResult {
     /// Callers that dispatch this variant are also responsible for resolving any pending local
     /// command-history entry that the composer staged before clearing the visible input.
     Command(SlashCommand),
+    /// A bare model service-tier command parsed by the composer.
+    ServiceTierCommand(ServiceTierCommand),
     /// An inline slash command and its trimmed argument text.
     ///
     /// The `TextElement` ranges are rebased into the argument string, while any pending local
@@ -399,7 +404,8 @@ pub(crate) struct ChatComposer {
     ide_context_active: bool,
     connectors_enabled: bool,
     plugins_command_enabled: bool,
-    fast_command_enabled: bool,
+    service_tier_commands_enabled: bool,
+    service_tier_commands: Vec<ServiceTierCommand>,
     goal_command_enabled: bool,
     personality_command_enabled: bool,
     realtime_conversation_enabled: bool,
@@ -489,7 +495,7 @@ impl ChatComposer {
             collaboration_modes_enabled: self.collaboration_modes_enabled,
             connectors_enabled: self.connectors_enabled,
             plugins_command_enabled: self.plugins_command_enabled,
-            fast_command_enabled: self.fast_command_enabled,
+            service_tier_commands_enabled: self.service_tier_commands_enabled,
             goal_command_enabled: self.goal_command_enabled,
             personality_command_enabled: self.personality_command_enabled,
             realtime_conversation_enabled: self.realtime_conversation_enabled,
@@ -580,7 +586,8 @@ impl ChatComposer {
             ide_context_active: false,
             connectors_enabled: false,
             plugins_command_enabled: false,
-            fast_command_enabled: false,
+            service_tier_commands_enabled: false,
+            service_tier_commands: Vec::new(),
             goal_command_enabled: false,
             personality_command_enabled: false,
             realtime_conversation_enabled: false,
@@ -693,8 +700,13 @@ impl ChatComposer {
         self.connectors_enabled = enabled;
     }
 
-    pub fn set_fast_command_enabled(&mut self, enabled: bool) {
-        self.fast_command_enabled = enabled;
+    pub fn set_service_tier_commands_enabled(&mut self, enabled: bool) {
+        self.service_tier_commands_enabled = enabled;
+    }
+
+    pub fn set_service_tier_commands(&mut self, commands: Vec<ServiceTierCommand>) {
+        self.service_tier_commands = commands;
+        self.sync_popups();
     }
 
     pub fn set_goal_command_enabled(&mut self, enabled: bool) {
@@ -1762,24 +1774,22 @@ impl ChatComposer {
                 // before applying completion.
                 let first_line = self.textarea.text().lines().next().unwrap_or("");
                 popup.on_composer_text_change(first_line.to_string());
-                let selected_cmd = popup.selected_item().map(|sel| {
-                    let CommandItem::Builtin(cmd) = sel;
-                    cmd
-                });
-                if let Some(cmd) = selected_cmd {
-                    if cmd == SlashCommand::Skills {
-                        self.stage_selected_slash_command_history(cmd);
+                if let Some(selected_cmd) = popup.selected_item() {
+                    let selected_command_text = format!("/{}", selected_cmd.command());
+                    if let CommandItem::Builtin(cmd) = selected_cmd
+                        && cmd == SlashCommand::Skills
+                    {
+                        self.stage_selected_slash_command_history(&CommandItem::Builtin(cmd));
                         self.textarea.set_text_clearing_elements("");
                         self.is_bash_mode = false;
                         return (InputResult::Command(cmd), true);
                     }
 
-                    let selected_command_text = format!("/{}", cmd.command());
                     let starts_with_cmd =
                         first_line.trim_start().starts_with(&selected_command_text);
                     if !starts_with_cmd {
                         self.textarea
-                            .set_text_clearing_elements(&format!("/{} ", cmd.command()));
+                            .set_text_clearing_elements(&format!("{selected_command_text} "));
                         if !self.textarea.text().is_empty() {
                             self.textarea.set_cursor(self.textarea.text().len());
                         }
@@ -1800,17 +1810,13 @@ impl ChatComposer {
                 // while the slash-command popup is active.
                 let first_line = self.textarea.text().lines().next().unwrap_or("");
                 popup.on_composer_text_change(first_line.to_string());
-                let selected_cmd = popup.selected_item().map(|sel| {
-                    let CommandItem::Builtin(cmd) = sel;
-                    cmd
-                });
-                if let Some(cmd) = selected_cmd {
-                    let starts_with_cmd = first_line
-                        .trim_start()
-                        .starts_with(&format!("/{}", cmd.command()));
+                if let Some(selected_cmd) = popup.selected_item() {
+                    let selected_command_text = format!("/{}", selected_cmd.command());
+                    let starts_with_cmd =
+                        first_line.trim_start().starts_with(&selected_command_text);
                     if !starts_with_cmd {
                         self.textarea
-                            .set_text_clearing_elements(&format!("/{} ", cmd.command()));
+                            .set_text_clearing_elements(&format!("{selected_command_text} "));
                         self.is_bash_mode = false;
                     }
                     if !self.textarea.text().is_empty() {
@@ -1825,11 +1831,18 @@ impl ChatComposer {
                 ..
             } => {
                 if let Some(sel) = popup.selected_item() {
-                    let CommandItem::Builtin(cmd) = sel;
-                    self.stage_selected_slash_command_history(cmd);
+                    self.stage_selected_slash_command_history(&sel);
                     self.textarea.set_text_clearing_elements("");
                     self.is_bash_mode = false;
-                    return (InputResult::Command(cmd), true);
+                    return (
+                        match sel {
+                            CommandItem::Builtin(cmd) => InputResult::Command(cmd),
+                            CommandItem::ServiceTier(command) => {
+                                InputResult::ServiceTierCommand(command)
+                            }
+                        },
+                        true,
+                    );
                 }
                 // Fallback to default newline handling if no command selected.
                 self.handle_key_event_without_popup(key_event)
@@ -2624,10 +2637,13 @@ impl ChatComposer {
         {
             let treat_as_plain_text = input_starts_with_space || name.contains('/');
             if !treat_as_plain_text {
-                let is_builtin =
-                    slash_commands::find_builtin_command(name, self.builtin_command_flags())
-                        .is_some();
-                if !is_builtin {
+                let is_known = find_slash_command(
+                    name,
+                    self.builtin_command_flags(),
+                    &self.service_tier_commands,
+                )
+                .is_some();
+                if !is_known {
                     let message = format!(
                         r#"Unrecognized command '/{name}'. Type "/" for a list of supported commands."#
                     );
@@ -2705,6 +2721,7 @@ impl ChatComposer {
             InputResult::Submitted { .. }
                 | InputResult::Queued { .. }
                 | InputResult::Command(_)
+                | InputResult::ServiceTierCommand(_)
                 | InputResult::CommandWithArgs(_, _, _)
         ) {
             self.textarea.enter_vim_normal_mode();
@@ -2845,21 +2862,28 @@ impl ChatComposer {
         if !rest.is_empty() {
             return None;
         }
-        let cmd = slash_commands::find_builtin_command(name, self.builtin_command_flags())?;
-        if cmd.supports_inline_args()
+        let command = find_slash_command(
+            name,
+            self.builtin_command_flags(),
+            &self.service_tier_commands,
+        )?;
+        if command.supports_inline_args()
             && parse_slash_name(text).is_some_and(|(_, full_rest, _)| !full_rest.is_empty())
         {
             return None;
         }
-        if self.reject_slash_command_if_unavailable(cmd) {
-            self.stage_slash_command_history(cmd);
+        if self.reject_slash_command_if_unavailable(&command) {
+            self.stage_slash_command_history(&command);
             self.record_pending_slash_command_history();
             return Some(InputResult::None);
         }
-        self.stage_slash_command_history(cmd);
+        self.stage_slash_command_history(&command);
         self.textarea.set_text_clearing_elements("");
         self.is_bash_mode = false;
-        Some(InputResult::Command(cmd))
+        Some(match command {
+            SlashCommandItem::Builtin(cmd) => InputResult::Command(cmd),
+            SlashCommandItem::ServiceTier(command) => InputResult::ServiceTierCommand(command),
+        })
     }
 
     /// Check if the input is a slash command with args (e.g., /review args) and dispatch it.
@@ -2878,23 +2902,30 @@ impl ChatComposer {
             return None;
         }
 
-        let cmd = slash_commands::find_builtin_command(name, self.builtin_command_flags())?;
+        let command = find_slash_command(
+            name,
+            self.builtin_command_flags(),
+            &self.service_tier_commands,
+        )?;
 
-        if !cmd.supports_inline_args() {
+        if !command.supports_inline_args() {
             return None;
         }
-        if self.reject_slash_command_if_unavailable(cmd) {
-            self.stage_slash_command_history(cmd);
+        if self.reject_slash_command_if_unavailable(&command) {
+            self.stage_slash_command_history(&command);
             self.record_pending_slash_command_history();
             return Some(InputResult::None);
         }
 
-        self.stage_slash_command_history(cmd);
+        self.stage_slash_command_history(&command);
 
         let mut args_elements =
             Self::slash_command_args_elements(rest, rest_offset, &self.textarea.text_elements());
         let trimmed_rest = rest.trim();
         args_elements = Self::trim_text_elements(rest, trimmed_rest, args_elements);
+        let SlashCommandItem::Builtin(cmd) = command else {
+            return None;
+        };
         Some(InputResult::CommandWithArgs(
             cmd,
             trimmed_rest.to_string(),
@@ -2928,13 +2959,13 @@ impl ChatComposer {
         Some((trimmed_rest.to_string(), args_elements))
     }
 
-    fn reject_slash_command_if_unavailable(&self, cmd: SlashCommand) -> bool {
-        if !self.is_task_running || cmd.available_during_task() {
+    fn reject_slash_command_if_unavailable(&self, command: &SlashCommandItem) -> bool {
+        if !self.is_task_running || command.available_during_task() {
             return false;
         }
         let message = format!(
             "'/{}' is disabled while a task is in progress.",
-            cmd.command()
+            command.command()
         );
         self.app_event_tx.send(AppEvent::InsertHistoryCell(Box::new(
             history_cell::new_error_event(message),
@@ -2965,8 +2996,8 @@ impl ChatComposer {
     /// Staging snapshots the rich composer state before the textarea is cleared. `ChatWidget`
     /// commits the staged entry after dispatch so command recall follows the submitted text, not
     /// the command outcome.
-    fn stage_slash_command_history(&mut self, cmd: SlashCommand) {
-        if cmd == SlashCommand::Clear {
+    fn stage_slash_command_history(&mut self, command: &SlashCommandItem) {
+        if matches!(command, SlashCommandItem::Builtin(SlashCommand::Clear)) {
             return;
         }
         self.stage_slash_command_history_text(self.textarea.text().trim().to_string());
@@ -2976,11 +3007,11 @@ impl ChatComposer {
     ///
     /// Popup filtering text can be partial, so recording the selected command avoids recalling
     /// `/di` after the user actually accepted `/diff`.
-    fn stage_selected_slash_command_history(&mut self, cmd: SlashCommand) {
-        if cmd == SlashCommand::Clear {
+    fn stage_selected_slash_command_history(&mut self, command: &CommandItem) {
+        if matches!(command, CommandItem::Builtin(SlashCommand::Clear)) {
             return;
         }
-        self.stage_slash_command_history_text(format!("/{}", cmd.command()));
+        self.stage_slash_command_history_text(format!("/{}", command.command()));
     }
 
     /// Store the provided command text and the current composer adornments in the pending slot.
@@ -3738,7 +3769,12 @@ impl ChatComposer {
     }
 
     fn is_known_slash_name(&self, name: &str) -> bool {
-        slash_commands::find_builtin_command(name, self.builtin_command_flags()).is_some()
+        find_slash_command(
+            name,
+            self.builtin_command_flags(),
+            &self.service_tier_commands,
+        )
+        .is_some()
     }
 
     /// If the cursor is currently within a slash command on the first line,
@@ -3780,7 +3816,11 @@ impl ChatComposer {
             return rest_after_name.is_empty();
         }
 
-        slash_commands::has_builtin_prefix(name, self.builtin_command_flags())
+        has_slash_command_prefix(
+            name,
+            self.builtin_command_flags(),
+            &self.service_tier_commands,
+        )
     }
 
     /// Synchronize `self.command_popup` with the current text in the
@@ -3826,23 +3866,26 @@ impl ChatComposer {
                     let collaboration_modes_enabled = self.collaboration_modes_enabled;
                     let connectors_enabled = self.connectors_enabled;
                     let plugins_command_enabled = self.plugins_command_enabled;
-                    let fast_command_enabled = self.fast_command_enabled;
+                    let service_tier_commands_enabled = self.service_tier_commands_enabled;
                     let goal_command_enabled = self.goal_command_enabled;
                     let personality_command_enabled = self.personality_command_enabled;
                     let realtime_conversation_enabled = self.realtime_conversation_enabled;
                     let audio_device_selection_enabled = self.audio_device_selection_enabled;
-                    let mut command_popup = CommandPopup::new(CommandPopupFlags {
-                        collaboration_modes_enabled,
-                        connectors_enabled,
-                        plugins_command_enabled,
-                        fast_command_enabled,
-                        goal_command_enabled,
-                        personality_command_enabled,
-                        realtime_conversation_enabled,
-                        audio_device_selection_enabled,
-                        windows_degraded_sandbox_active: self.windows_degraded_sandbox_active,
-                        side_conversation_active: self.side_conversation_active,
-                    });
+                    let mut command_popup = CommandPopup::new(
+                        CommandPopupFlags {
+                            collaboration_modes_enabled,
+                            connectors_enabled,
+                            plugins_command_enabled,
+                            service_tier_commands_enabled,
+                            goal_command_enabled,
+                            personality_command_enabled,
+                            realtime_conversation_enabled,
+                            audio_device_selection_enabled,
+                            windows_degraded_sandbox_active: self.windows_degraded_sandbox_active,
+                            side_conversation_active: self.side_conversation_active,
+                        },
+                        self.service_tier_commands.clone(),
+                    );
                     command_popup.on_composer_text_change(first_line.to_string());
                     self.active_popup = ActivePopup::Command(command_popup);
                 }
@@ -7548,6 +7591,9 @@ mod tests {
                 Some(CommandItem::Builtin(cmd)) => {
                     assert_eq!(cmd.command(), "model")
                 }
+                Some(CommandItem::ServiceTier(command)) => {
+                    panic!("expected model command, got service tier {command:?}")
+                }
                 None => panic!("no selected command for '/mo'"),
             },
             _ => panic!("slash popup not active after typing '/mo'"),
@@ -7601,12 +7647,47 @@ mod tests {
                 Some(CommandItem::Builtin(cmd)) => {
                     assert_eq!(cmd.command(), "resume")
                 }
+                Some(CommandItem::ServiceTier(command)) => {
+                    panic!("expected resume command, got service tier {command:?}")
+                }
                 None => panic!("no selected command for '/res'"),
             },
             _ => panic!("slash popup not active after typing '/res'"),
         }
     }
 
+    #[test]
+    fn service_tier_slash_command_dispatches_from_catalog_name() {
+        let (tx, _rx) = unbounded_channel::<AppEvent>();
+        let sender = AppEventSender::new(tx);
+        let mut composer = ChatComposer::new(
+            /*has_input_focus*/ true,
+            sender,
+            /*enhanced_keys_supported*/ false,
+            "Ask Codex to do anything".to_string(),
+            /*disable_paste_burst*/ false,
+        );
+        composer.set_service_tier_commands_enabled(/*enabled*/ true);
+        composer.set_service_tier_commands(vec![ServiceTierCommand {
+            id: "priority".to_string(),
+            name: "fast".to_string(),
+            description: "Fastest inference with increased plan usage".to_string(),
+        }]);
+        type_chars_humanlike(&mut composer, &['/', 'f', 'a', 's', 't']);
+
+        let (result, _needs_redraw) =
+            composer.handle_key_event(KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE));
+
+        assert_eq!(
+            result,
+            InputResult::ServiceTierCommand(ServiceTierCommand {
+                id: "priority".to_string(),
+                name: "fast".to_string(),
+                description: "Fastest inference with increased plan usage".to_string(),
+            })
+        );
+    }
+
     fn flush_after_paste_burst(composer: &mut ChatComposer) -> bool {
         std::thread::sleep(PasteBurst::recommended_active_flush_delay());
         composer.flush_paste_burst_if_due()
@@ -7664,6 +7745,9 @@ mod tests {
             InputResult::CommandWithArgs(_, _, _) => {
                 panic!("expected command dispatch without args for '/init'")
             }
+            InputResult::ServiceTierCommand(command) => {
+                panic!("expected init command, got service tier {command:?}")
+            }
             InputResult::Submitted { text, .. } => {
                 panic!("expected command dispatch, but composer submitted literal text: {text}")
             }
@@ -7833,7 +7917,7 @@ mod tests {
 
         assert_queued_slash("/compact");
         assert_queued_slash("/review check regressions");
-        assert_queued_slash("/fast on");
+        assert_queued_slash("/fast");
         assert_queued_slash("/does-not-exist");
     }
 
@@ -8110,6 +8194,9 @@ mod tests {
             InputResult::CommandWithArgs(_, _, _) => {
                 panic!("expected command dispatch without args for '/diff'")
             }
+            InputResult::ServiceTierCommand(command) => {
+                panic!("expected diff command, got service tier {command:?}")
+            }
             InputResult::Submitted { text, .. } => {
                 panic!("expected command dispatch after Tab completion, got literal submit: {text}")
             }
@@ -8304,6 +8391,9 @@ mod tests {
             InputResult::CommandWithArgs(_, _, _) => {
                 panic!("expected command dispatch without args for '/mention'")
             }
+            InputResult::ServiceTierCommand(command) => {
+                panic!("expected mention command, got service tier {command:?}")
+            }
             InputResult::Submitted { text, .. } => {
                 panic!("expected command dispatch, but composer submitted literal text: {text}")
             }
diff --git a/codex-rs/tui/src/bottom_pane/command_popup.rs b/codex-rs/tui/src/bottom_pane/command_popup.rs
index 1618d64025..714fe9dd44 100644
--- a/codex-rs/tui/src/bottom_pane/command_popup.rs
+++ b/codex-rs/tui/src/bottom_pane/command_popup.rs
@@ -9,7 +9,10 @@ use super::selection_popup_common::ColumnWidthMode;
 use super::selection_popup_common::GenericDisplayRow;
 use super::selection_popup_common::measure_rows_height_with_col_width_mode;
 use super::selection_popup_common::render_rows_with_col_width_mode;
-use super::slash_commands;
+use super::slash_commands::BuiltinCommandFlags;
+use super::slash_commands::ServiceTierCommand;
+use super::slash_commands::SlashCommandItem;
+use super::slash_commands::commands_for_input;
 use crate::render::Insets;
 use crate::render::RectExt;
 use crate::slash_command::SlashCommand;
@@ -23,14 +26,15 @@ const COMMAND_COLUMN_WIDTH: ColumnWidthConfig = ColumnWidthConfig::new(
 );
 
 /// A selectable item in the popup.
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) enum CommandItem {
     Builtin(SlashCommand),
+    ServiceTier(ServiceTierCommand),
 }
 
 pub(crate) struct CommandPopup {
     command_filter: String,
-    builtins: Vec<(&'static str, SlashCommand)>,
+    commands: Vec<CommandItem>,
     state: ScrollState,
 }
 
@@ -39,7 +43,7 @@ pub(crate) struct CommandPopupFlags {
     pub(crate) collaboration_modes_enabled: bool,
     pub(crate) connectors_enabled: bool,
     pub(crate) plugins_command_enabled: bool,
-    pub(crate) fast_command_enabled: bool,
+    pub(crate) service_tier_commands_enabled: bool,
     pub(crate) goal_command_enabled: bool,
     pub(crate) personality_command_enabled: bool,
     pub(crate) realtime_conversation_enabled: bool,
@@ -48,13 +52,13 @@ pub(crate) struct CommandPopupFlags {
     pub(crate) side_conversation_active: bool,
 }
 
-impl From<CommandPopupFlags> for slash_commands::BuiltinCommandFlags {
+impl From<CommandPopupFlags> for BuiltinCommandFlags {
     fn from(value: CommandPopupFlags) -> Self {
         Self {
             collaboration_modes_enabled: value.collaboration_modes_enabled,
             connectors_enabled: value.connectors_enabled,
             plugins_command_enabled: value.plugins_command_enabled,
-            fast_command_enabled: value.fast_command_enabled,
+            service_tier_commands_enabled: value.service_tier_commands_enabled,
             goal_command_enabled: value.goal_command_enabled,
             personality_command_enabled: value.personality_command_enabled,
             realtime_conversation_enabled: value.realtime_conversation_enabled,
@@ -66,17 +70,23 @@ impl From<CommandPopupFlags> for slash_commands::BuiltinCommandFlags {
 }
 
 impl CommandPopup {
-    pub(crate) fn new(flags: CommandPopupFlags) -> Self {
+    pub(crate) fn new(
+        flags: CommandPopupFlags,
+        service_tier_commands: Vec<ServiceTierCommand>,
+    ) -> Self {
         // Keep built-in availability in sync with the composer.
-        let builtins: Vec<(&'static str, SlashCommand)> =
-            slash_commands::builtins_for_input(flags.into())
-                .into_iter()
-                .filter(|(name, _)| !name.starts_with("debug"))
-                .filter(|(_, cmd)| *cmd != SlashCommand::Apps)
-                .collect();
+        let commands = commands_for_input(flags.into(), &service_tier_commands)
+            .into_iter()
+            .filter_map(|command| match command {
+                SlashCommandItem::Builtin(cmd) => (!cmd.command().starts_with("debug")
+                    && cmd != SlashCommand::Apps)
+                    .then_some(CommandItem::Builtin(cmd)),
+                SlashCommandItem::ServiceTier(command) => Some(CommandItem::ServiceTier(command)),
+            })
+            .collect();
         Self {
             command_filter: String::new(),
-            builtins,
+            commands,
             state: ScrollState::new(),
         }
     }
@@ -133,11 +143,11 @@ impl CommandPopup {
         let filter = self.command_filter.trim();
         let mut out: Vec<(CommandItem, Option<Vec<usize>>)> = Vec::new();
         if filter.is_empty() {
-            for (_, cmd) in self.builtins.iter() {
-                if ALIAS_COMMANDS.contains(cmd) {
+            for command in self.commands.iter() {
+                if matches!(command, CommandItem::Builtin(cmd) if ALIAS_COMMANDS.contains(cmd)) {
                     continue;
                 }
-                out.push((CommandItem::Builtin(*cmd), None));
+                out.push((command.clone(), None));
             }
             return out;
         }
@@ -169,8 +179,9 @@ impl CommandPopup {
                 }
             };
 
-        for (_, cmd) in self.builtins.iter() {
-            push_match(CommandItem::Builtin(*cmd), cmd.command(), None, 0);
+        for command in self.commands.iter() {
+            let display = command.command();
+            push_match(command.clone(), display, None, 0);
         }
 
         out.extend(exact);
@@ -189,9 +200,8 @@ impl CommandPopup {
         matches
             .into_iter()
             .map(|(item, indices)| {
-                let CommandItem::Builtin(cmd) = item;
-                let name = format!("/{}", cmd.command());
-                let description = cmd.description().to_string();
+                let name = format!("/{}", item.command());
+                let description = item.description().to_string();
                 GenericDisplayRow {
                     name,
                     name_prefix_spans: Vec::new(),
@@ -227,7 +237,23 @@ impl CommandPopup {
         let matches = self.filtered_items();
         self.state
             .selected_idx
-            .and_then(|idx| matches.get(idx).copied())
+            .and_then(|idx| matches.get(idx).cloned())
+    }
+}
+
+impl CommandItem {
+    pub(crate) fn command(&self) -> &str {
+        match self {
+            Self::Builtin(cmd) => cmd.command(),
+            Self::ServiceTier(command) => &command.name,
+        }
+    }
+
+    fn description(&self) -> &str {
+        match self {
+            Self::Builtin(cmd) => cmd.description(),
+            Self::ServiceTier(command) => &command.description,
+        }
     }
 }
 
@@ -255,7 +281,7 @@ mod tests {
 
     #[test]
     fn filter_includes_init_when_typing_prefix() {
-        let mut popup = CommandPopup::new(CommandPopupFlags::default());
+        let mut popup = CommandPopup::new(CommandPopupFlags::default(), Vec::new());
         // Simulate the composer line starting with '/in' so the popup filters
         // matching commands by prefix.
         popup.on_composer_text_change("/in".to_string());
@@ -265,6 +291,7 @@ mod tests {
         let matches = popup.filtered_items();
         let has_init = matches.iter().any(|item| match item {
             CommandItem::Builtin(cmd) => cmd.command() == "init",
+            CommandItem::ServiceTier(_) => false,
         });
         assert!(
             has_init,
@@ -274,7 +301,7 @@ mod tests {
 
     #[test]
     fn selecting_init_by_exact_match() {
-        let mut popup = CommandPopup::new(CommandPopupFlags::default());
+        let mut popup = CommandPopup::new(CommandPopupFlags::default(), Vec::new());
         popup.on_composer_text_change("/init".to_string());
 
         // When an exact match exists, the selected command should be that
@@ -282,57 +309,106 @@ mod tests {
         let selected = popup.selected_item();
         match selected {
             Some(CommandItem::Builtin(cmd)) => assert_eq!(cmd.command(), "init"),
+            Some(CommandItem::ServiceTier(command)) => {
+                panic!("expected init command, got service tier {command:?}")
+            }
             None => panic!("expected a selected command for exact match"),
         }
     }
 
     #[test]
     fn model_is_first_suggestion_for_mo() {
-        let mut popup = CommandPopup::new(CommandPopupFlags::default());
+        let mut popup = CommandPopup::new(CommandPopupFlags::default(), Vec::new());
         popup.on_composer_text_change("/mo".to_string());
         let matches = popup.filtered_items();
         match matches.first() {
             Some(CommandItem::Builtin(cmd)) => assert_eq!(cmd.command(), "model"),
+            Some(CommandItem::ServiceTier(command)) => {
+                panic!("expected model command, got service tier {command:?}")
+            }
             None => panic!("expected at least one match for '/mo'"),
         }
     }
 
+    #[test]
+    fn service_tier_command_uses_catalog_name_and_description() {
+        let mut popup = CommandPopup::new(
+            CommandPopupFlags {
+                service_tier_commands_enabled: true,
+                ..CommandPopupFlags::default()
+            },
+            vec![ServiceTierCommand {
+                id: "priority".to_string(),
+                name: "fast".to_string(),
+                description: "Fastest inference with increased plan usage".to_string(),
+            }],
+        );
+        popup.on_composer_text_change("/fa".to_string());
+
+        match popup.selected_item() {
+            Some(CommandItem::ServiceTier(command)) => assert_eq!(
+                command,
+                ServiceTierCommand {
+                    id: "priority".to_string(),
+                    name: "fast".to_string(),
+                    description: "Fastest inference with increased plan usage".to_string(),
+                }
+            ),
+            other => panic!("expected fast service tier to be selected, got {other:?}"),
+        }
+        let rows = popup.rows_from_matches(popup.filtered());
+        assert_eq!(
+            rows.first().and_then(|row| row.description.as_deref()),
+            Some("Fastest inference with increased plan usage")
+        );
+    }
+
     #[test]
     fn filtered_commands_keep_presentation_order_for_prefix() {
-        let mut popup = CommandPopup::new(CommandPopupFlags::default());
+        let mut popup = CommandPopup::new(CommandPopupFlags::default(), Vec::new());
         popup.on_composer_text_change("/m".to_string());
 
-        let cmds: Vec<&str> = popup
+        let cmds: Vec<String> = popup
             .filtered_items()
             .into_iter()
             .map(|item| match item {
-                CommandItem::Builtin(cmd) => cmd.command(),
+                CommandItem::Builtin(cmd) => cmd.command().to_string(),
+                CommandItem::ServiceTier(command) => command.name,
             })
             .collect();
-        assert_eq!(cmds, vec!["model", "memories", "mention", "mcp"]);
+        assert_eq!(
+            cmds,
+            vec![
+                "model".to_string(),
+                "memories".to_string(),
+                "mention".to_string(),
+                "mcp".to_string()
+            ]
+        );
     }
 
     #[test]
     fn prefix_filter_limits_matches_for_ac() {
-        let mut popup = CommandPopup::new(CommandPopupFlags::default());
+        let mut popup = CommandPopup::new(CommandPopupFlags::default(), Vec::new());
         popup.on_composer_text_change("/ac".to_string());
 
-        let cmds: Vec<&str> = popup
+        let cmds: Vec<String> = popup
             .filtered_items()
             .into_iter()
             .map(|item| match item {
-                CommandItem::Builtin(cmd) => cmd.command(),
+                CommandItem::Builtin(cmd) => cmd.command().to_string(),
+                CommandItem::ServiceTier(command) => command.name,
             })
             .collect();
         assert!(
-            !cmds.contains(&"compact"),
+            !cmds.iter().any(|cmd| cmd == "compact"),
             "expected prefix search for '/ac' to exclude 'compact', got {cmds:?}"
         );
     }
 
     #[test]
     fn quit_hidden_in_empty_filter_but_shown_for_prefix() {
-        let mut popup = CommandPopup::new(CommandPopupFlags::default());
+        let mut popup = CommandPopup::new(CommandPopupFlags::default(), Vec::new());
         popup.on_composer_text_change("/".to_string());
         let items = popup.filtered_items();
         assert!(!items.contains(&CommandItem::Builtin(SlashCommand::Quit)));
@@ -344,159 +420,187 @@ mod tests {
 
     #[test]
     fn collab_command_hidden_when_collaboration_modes_disabled() {
-        let mut popup = CommandPopup::new(CommandPopupFlags::default());
+        let mut popup = CommandPopup::new(CommandPopupFlags::default(), Vec::new());
         popup.on_composer_text_change("/".to_string());
 
-        let cmds: Vec<&str> = popup
+        let cmds: Vec<String> = popup
             .filtered_items()
             .into_iter()
             .map(|item| match item {
-                CommandItem::Builtin(cmd) => cmd.command(),
+                CommandItem::Builtin(cmd) => cmd.command().to_string(),
+                CommandItem::ServiceTier(command) => command.name,
             })
             .collect();
         assert!(
-            !cmds.contains(&"collab"),
+            !cmds.iter().any(|cmd| cmd == "collab"),
             "expected '/collab' to be hidden when collaboration modes are disabled, got {cmds:?}"
         );
         assert!(
-            !cmds.contains(&"plan"),
+            !cmds.iter().any(|cmd| cmd == "plan"),
             "expected '/plan' to be hidden when collaboration modes are disabled, got {cmds:?}"
         );
     }
 
     #[test]
     fn collab_command_visible_when_collaboration_modes_enabled() {
-        let mut popup = CommandPopup::new(CommandPopupFlags {
-            collaboration_modes_enabled: true,
-            connectors_enabled: false,
-            plugins_command_enabled: false,
-            fast_command_enabled: false,
-            goal_command_enabled: false,
-            personality_command_enabled: true,
-            realtime_conversation_enabled: false,
-            audio_device_selection_enabled: false,
-            windows_degraded_sandbox_active: false,
-            side_conversation_active: false,
-        });
+        let mut popup = CommandPopup::new(
+            CommandPopupFlags {
+                collaboration_modes_enabled: true,
+                connectors_enabled: false,
+                plugins_command_enabled: false,
+                service_tier_commands_enabled: false,
+                goal_command_enabled: false,
+                personality_command_enabled: true,
+                realtime_conversation_enabled: false,
+                audio_device_selection_enabled: false,
+                windows_degraded_sandbox_active: false,
+                side_conversation_active: false,
+            },
+            Vec::new(),
+        );
         popup.on_composer_text_change("/collab".to_string());
 
         match popup.selected_item() {
             Some(CommandItem::Builtin(cmd)) => assert_eq!(cmd.command(), "collab"),
+            Some(CommandItem::ServiceTier(command)) => {
+                panic!("expected collab command, got service tier {command:?}")
+            }
             other => panic!("expected collab to be selected for exact match, got {other:?}"),
         }
     }
 
     #[test]
     fn plan_command_visible_when_collaboration_modes_enabled() {
-        let mut popup = CommandPopup::new(CommandPopupFlags {
-            collaboration_modes_enabled: true,
-            connectors_enabled: false,
-            plugins_command_enabled: false,
-            fast_command_enabled: false,
-            goal_command_enabled: false,
-            personality_command_enabled: true,
-            realtime_conversation_enabled: false,
-            audio_device_selection_enabled: false,
-            windows_degraded_sandbox_active: false,
-            side_conversation_active: false,
-        });
+        let mut popup = CommandPopup::new(
+            CommandPopupFlags {
+                collaboration_modes_enabled: true,
+                connectors_enabled: false,
+                plugins_command_enabled: false,
+                service_tier_commands_enabled: false,
+                goal_command_enabled: false,
+                personality_command_enabled: true,
+                realtime_conversation_enabled: false,
+                audio_device_selection_enabled: false,
+                windows_degraded_sandbox_active: false,
+                side_conversation_active: false,
+            },
+            Vec::new(),
+        );
         popup.on_composer_text_change("/plan".to_string());
 
         match popup.selected_item() {
             Some(CommandItem::Builtin(cmd)) => assert_eq!(cmd.command(), "plan"),
+            Some(CommandItem::ServiceTier(command)) => {
+                panic!("expected plan command, got service tier {command:?}")
+            }
             other => panic!("expected plan to be selected for exact match, got {other:?}"),
         }
     }
 
     #[test]
     fn personality_command_hidden_when_disabled() {
-        let mut popup = CommandPopup::new(CommandPopupFlags {
-            collaboration_modes_enabled: true,
-            connectors_enabled: false,
-            plugins_command_enabled: false,
-            fast_command_enabled: false,
-            goal_command_enabled: false,
-            personality_command_enabled: false,
-            realtime_conversation_enabled: false,
-            audio_device_selection_enabled: false,
-            windows_degraded_sandbox_active: false,
-            side_conversation_active: false,
-        });
+        let mut popup = CommandPopup::new(
+            CommandPopupFlags {
+                collaboration_modes_enabled: true,
+                connectors_enabled: false,
+                plugins_command_enabled: false,
+                service_tier_commands_enabled: false,
+                goal_command_enabled: false,
+                personality_command_enabled: false,
+                realtime_conversation_enabled: false,
+                audio_device_selection_enabled: false,
+                windows_degraded_sandbox_active: false,
+                side_conversation_active: false,
+            },
+            Vec::new(),
+        );
         popup.on_composer_text_change("/pers".to_string());
 
-        let cmds: Vec<&str> = popup
+        let cmds: Vec<String> = popup
             .filtered_items()
             .into_iter()
             .map(|item| match item {
-                CommandItem::Builtin(cmd) => cmd.command(),
+                CommandItem::Builtin(cmd) => cmd.command().to_string(),
+                CommandItem::ServiceTier(command) => command.name,
             })
             .collect();
         assert!(
-            !cmds.contains(&"personality"),
+            !cmds.iter().any(|cmd| cmd == "personality"),
             "expected '/personality' to be hidden when disabled, got {cmds:?}"
         );
     }
 
     #[test]
     fn personality_command_visible_when_enabled() {
-        let mut popup = CommandPopup::new(CommandPopupFlags {
-            collaboration_modes_enabled: true,
-            connectors_enabled: false,
-            plugins_command_enabled: false,
-            fast_command_enabled: false,
-            goal_command_enabled: false,
-            personality_command_enabled: true,
-            realtime_conversation_enabled: false,
-            audio_device_selection_enabled: false,
-            windows_degraded_sandbox_active: false,
-            side_conversation_active: false,
-        });
+        let mut popup = CommandPopup::new(
+            CommandPopupFlags {
+                collaboration_modes_enabled: true,
+                connectors_enabled: false,
+                plugins_command_enabled: false,
+                service_tier_commands_enabled: false,
+                goal_command_enabled: false,
+                personality_command_enabled: true,
+                realtime_conversation_enabled: false,
+                audio_device_selection_enabled: false,
+                windows_degraded_sandbox_active: false,
+                side_conversation_active: false,
+            },
+            Vec::new(),
+        );
         popup.on_composer_text_change("/personality".to_string());
 
         match popup.selected_item() {
             Some(CommandItem::Builtin(cmd)) => assert_eq!(cmd.command(), "personality"),
+            Some(CommandItem::ServiceTier(command)) => {
+                panic!("expected personality command, got service tier {command:?}")
+            }
             other => panic!("expected personality to be selected for exact match, got {other:?}"),
         }
     }
 
     #[test]
     fn settings_command_hidden_when_audio_device_selection_is_disabled() {
-        let mut popup = CommandPopup::new(CommandPopupFlags {
-            collaboration_modes_enabled: false,
-            connectors_enabled: false,
-            plugins_command_enabled: false,
-            fast_command_enabled: false,
-            goal_command_enabled: false,
-            personality_command_enabled: true,
-            realtime_conversation_enabled: true,
-            audio_device_selection_enabled: false,
-            windows_degraded_sandbox_active: false,
-            side_conversation_active: false,
-        });
+        let mut popup = CommandPopup::new(
+            CommandPopupFlags {
+                collaboration_modes_enabled: false,
+                connectors_enabled: false,
+                plugins_command_enabled: false,
+                service_tier_commands_enabled: false,
+                goal_command_enabled: false,
+                personality_command_enabled: true,
+                realtime_conversation_enabled: true,
+                audio_device_selection_enabled: false,
+                windows_degraded_sandbox_active: false,
+                side_conversation_active: false,
+            },
+            Vec::new(),
+        );
         popup.on_composer_text_change("/aud".to_string());
 
-        let cmds: Vec<&str> = popup
+        let cmds: Vec<String> = popup
             .filtered_items()
             .into_iter()
             .map(|item| match item {
-                CommandItem::Builtin(cmd) => cmd.command(),
+                CommandItem::Builtin(cmd) => cmd.command().to_string(),
+                CommandItem::ServiceTier(command) => command.name,
             })
             .collect();
 
         assert!(
-            !cmds.contains(&"settings"),
+            !cmds.iter().any(|cmd| cmd == "settings"),
             "expected '/settings' to be hidden when audio device selection is disabled, got {cmds:?}"
         );
     }
 
     #[test]
     fn debug_commands_are_hidden_from_popup() {
-        let popup = CommandPopup::new(CommandPopupFlags::default());
-        let cmds: Vec<&str> = popup
+        let popup = CommandPopup::new(CommandPopupFlags::default(), Vec::new());
+        let cmds: Vec<String> = popup
             .filtered_items()
             .into_iter()
             .map(|item| match item {
-                CommandItem::Builtin(cmd) => cmd.command(),
+                CommandItem::Builtin(cmd) => cmd.command().to_string(),
+                CommandItem::ServiceTier(command) => command.name,
             })
             .collect();
 
diff --git a/codex-rs/tui/src/bottom_pane/mod.rs b/codex-rs/tui/src/bottom_pane/mod.rs
index 71075f3d06..5746816b24 100644
--- a/codex-rs/tui/src/bottom_pane/mod.rs
+++ b/codex-rs/tui/src/bottom_pane/mod.rs
@@ -113,6 +113,7 @@ pub(crate) use list_selection_view::SideContentWidth;
 pub(crate) use list_selection_view::popup_content_width;
 pub(crate) use list_selection_view::side_by_side_layout_widths;
 pub(crate) use memories_settings_view::MemoriesSettingsView;
+use slash_commands::ServiceTierCommand;
 mod feedback_view;
 mod hooks_browser_view;
 pub(crate) use feedback_view::FeedbackAudience;
@@ -394,8 +395,13 @@ impl BottomPane {
         self.request_redraw();
     }
 
-    pub fn set_fast_command_enabled(&mut self, enabled: bool) {
-        self.composer.set_fast_command_enabled(enabled);
+    pub fn set_service_tier_commands_enabled(&mut self, enabled: bool) {
+        self.composer.set_service_tier_commands_enabled(enabled);
+        self.request_redraw();
+    }
+
+    pub fn set_service_tier_commands(&mut self, commands: Vec<ServiceTierCommand>) {
+        self.composer.set_service_tier_commands(commands);
         self.request_redraw();
     }
 
diff --git a/codex-rs/tui/src/bottom_pane/slash_commands.rs b/codex-rs/tui/src/bottom_pane/slash_commands.rs
index c253d49b04..6966b28b81 100644
--- a/codex-rs/tui/src/bottom_pane/slash_commands.rs
+++ b/codex-rs/tui/src/bottom_pane/slash_commands.rs
@@ -1,4 +1,4 @@
-//! Shared helpers for filtering and matching built-in slash commands.
+//! Shared helpers for filtering and matching built-in and model service-tier slash commands.
 //!
 //! The same sandbox- and feature-gating rules are used by both the composer
 //! and the command popup. Centralizing them here keeps those call sites small
@@ -10,12 +10,55 @@ use codex_utils_fuzzy_match::fuzzy_match;
 use crate::slash_command::SlashCommand;
 use crate::slash_command::built_in_slash_commands;
 
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub(crate) struct ServiceTierCommand {
+    pub(crate) id: String,
+    pub(crate) name: String,
+    pub(crate) description: String,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub(crate) enum SlashCommandItem {
+    Builtin(SlashCommand),
+    ServiceTier(ServiceTierCommand),
+}
+
+impl SlashCommandItem {
+    pub(crate) fn command(&self) -> &str {
+        match self {
+            Self::Builtin(cmd) => cmd.command(),
+            Self::ServiceTier(command) => &command.name,
+        }
+    }
+
+    pub(crate) fn supports_inline_args(&self) -> bool {
+        match self {
+            Self::Builtin(cmd) => cmd.supports_inline_args(),
+            Self::ServiceTier(_) => false,
+        }
+    }
+
+    pub(crate) fn available_in_side_conversation(&self) -> bool {
+        match self {
+            Self::Builtin(cmd) => cmd.available_in_side_conversation(),
+            Self::ServiceTier(_) => false,
+        }
+    }
+
+    pub(crate) fn available_during_task(&self) -> bool {
+        match self {
+            Self::Builtin(cmd) => cmd.available_during_task(),
+            Self::ServiceTier(_) => false,
+        }
+    }
+}
+
 #[derive(Clone, Copy, Debug, Default)]
 pub(crate) struct BuiltinCommandFlags {
     pub(crate) collaboration_modes_enabled: bool,
     pub(crate) connectors_enabled: bool,
     pub(crate) plugins_command_enabled: bool,
-    pub(crate) fast_command_enabled: bool,
+    pub(crate) service_tier_commands_enabled: bool,
     pub(crate) goal_command_enabled: bool,
     pub(crate) personality_command_enabled: bool,
     pub(crate) realtime_conversation_enabled: bool,
@@ -35,7 +78,6 @@ pub(crate) fn builtins_for_input(flags: BuiltinCommandFlags) -> Vec<(&'static st
         })
         .filter(|(_, cmd)| flags.connectors_enabled || *cmd != SlashCommand::Apps)
         .filter(|(_, cmd)| flags.plugins_command_enabled || *cmd != SlashCommand::Plugins)
-        .filter(|(_, cmd)| flags.fast_command_enabled || *cmd != SlashCommand::Fast)
         .filter(|(_, cmd)| flags.goal_command_enabled || *cmd != SlashCommand::Goal)
         .filter(|(_, cmd)| flags.personality_command_enabled || *cmd != SlashCommand::Personality)
         .filter(|(_, cmd)| flags.realtime_conversation_enabled || *cmd != SlashCommand::Realtime)
@@ -44,6 +86,29 @@ pub(crate) fn builtins_for_input(flags: BuiltinCommandFlags) -> Vec<(&'static st
         .collect()
 }
 
+pub(crate) fn commands_for_input(
+    flags: BuiltinCommandFlags,
+    service_tier_commands: &[ServiceTierCommand],
+) -> Vec<SlashCommandItem> {
+    let mut commands = Vec::new();
+    let tiers_enabled = flags.service_tier_commands_enabled;
+    for (_, cmd) in builtins_for_input(flags) {
+        commands.push(SlashCommandItem::Builtin(cmd));
+        if cmd == SlashCommand::Model && tiers_enabled {
+            commands.extend(
+                service_tier_commands
+                    .iter()
+                    .cloned()
+                    .map(SlashCommandItem::ServiceTier),
+            );
+        }
+    }
+    commands
+        .into_iter()
+        .filter(|cmd| !flags.side_conversation_active || cmd.available_in_side_conversation())
+        .collect()
+}
+
 /// Find a single built-in command by exact name, after applying feature gating.
 ///
 /// Side-conversation gating is intentionally enforced by dispatch rather than exact lookup so a
@@ -59,24 +124,49 @@ pub(crate) fn find_builtin_command(name: &str, flags: BuiltinCommandFlags) -> Op
     .then_some(cmd)
 }
 
-/// Whether any visible built-in fuzzily matches the provided prefix.
-pub(crate) fn has_builtin_prefix(name: &str, flags: BuiltinCommandFlags) -> bool {
-    builtins_for_input(flags)
+pub(crate) fn find_slash_command(
+    name: &str,
+    flags: BuiltinCommandFlags,
+    service_tier_commands: &[ServiceTierCommand],
+) -> Option<SlashCommandItem> {
+    if let Some(cmd) = find_builtin_command(name, flags) {
+        return Some(SlashCommandItem::Builtin(cmd));
+    }
+
+    let tiers_enabled = flags.service_tier_commands_enabled;
+    tiers_enabled
+        .then(|| {
+            service_tier_commands
+                .iter()
+                .find(|command| command.name == name)
+                .cloned()
+                .map(SlashCommandItem::ServiceTier)
+        })
+        .flatten()
+}
+
+pub(crate) fn has_slash_command_prefix(
+    name: &str,
+    flags: BuiltinCommandFlags,
+    service_tier_commands: &[ServiceTierCommand],
+) -> bool {
+    commands_for_input(flags, service_tier_commands)
         .into_iter()
-        .any(|(command_name, _)| fuzzy_match(command_name, name).is_some())
+        .any(|command| fuzzy_match(command.command(), name).is_some())
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
     use pretty_assertions::assert_eq;
+    use std::slice::from_ref;
 
     fn all_enabled_flags() -> BuiltinCommandFlags {
         BuiltinCommandFlags {
             collaboration_modes_enabled: true,
             connectors_enabled: true,
             plugins_command_enabled: true,
-            fast_command_enabled: true,
+            service_tier_commands_enabled: true,
             goal_command_enabled: true,
             personality_command_enabled: true,
             realtime_conversation_enabled: true,
@@ -117,10 +207,49 @@ mod tests {
     }
 
     #[test]
-    fn fast_command_is_hidden_when_disabled() {
+    fn service_tier_commands_are_hidden_when_disabled() {
         let mut flags = all_enabled_flags();
-        flags.fast_command_enabled = false;
-        assert_eq!(find_builtin_command("fast", flags), None);
+        flags.service_tier_commands_enabled = false;
+        let commands = vec![ServiceTierCommand {
+            id: "priority".to_string(),
+            name: "fast".to_string(),
+            description: "fastest inference".to_string(),
+        }];
+
+        assert_eq!(find_slash_command("fast", flags, &commands), None);
+    }
+
+    #[test]
+    fn all_service_tiers_are_exposed_as_commands_after_model() {
+        let commands = vec![
+            ServiceTierCommand {
+                id: "priority".to_string(),
+                name: "fast".to_string(),
+                description: "fastest inference".to_string(),
+            },
+            ServiceTierCommand {
+                id: "batch".to_string(),
+                name: "slow".to_string(),
+                description: "slower inference with lower priority".to_string(),
+            },
+        ];
+
+        let items = commands_for_input(all_enabled_flags(), &commands);
+        let model_idx = items
+            .iter()
+            .position(|item| matches!(item, SlashCommandItem::Builtin(SlashCommand::Model)))
+            .expect("model command should be visible");
+        let inserted = items
+            .into_iter()
+            .skip(model_idx + 1)
+            .take(commands.len())
+            .collect::<Vec<_>>();
+        let expected = commands
+            .into_iter()
+            .map(SlashCommandItem::ServiceTier)
+            .collect::<Vec<_>>();
+
+        assert_eq!(inserted, expected);
     }
 
     #[test]
@@ -188,4 +317,22 @@ mod tests {
             Some(SlashCommand::Review)
         );
     }
+
+    #[test]
+    fn side_conversation_exact_lookup_still_resolves_service_tier_commands_for_dispatch_error() {
+        let command = ServiceTierCommand {
+            id: "priority".to_string(),
+            name: "fast".to_string(),
+            description: "fastest inference".to_string(),
+        };
+        let flags = BuiltinCommandFlags {
+            side_conversation_active: true,
+            ..all_enabled_flags()
+        };
+
+        assert_eq!(
+            find_slash_command("fast", flags, from_ref(&command)),
+            Some(SlashCommandItem::ServiceTier(command))
+        );
+    }
 }
diff --git a/codex-rs/tui/src/chatwidget.rs b/codex-rs/tui/src/chatwidget.rs
index b65f8b1c4d..68e59d9409 100644
--- a/codex-rs/tui/src/chatwidget.rs
+++ b/codex-rs/tui/src/chatwidget.rs
@@ -150,7 +150,6 @@ use codex_protocol::config_types::CollaborationMode;
 use codex_protocol::config_types::CollaborationModeMask;
 use codex_protocol::config_types::ModeKind;
 use codex_protocol::config_types::Personality;
-use codex_protocol::config_types::ServiceTier;
 use codex_protocol::config_types::Settings;
 #[cfg(target_os = "windows")]
 use codex_protocol::config_types::WindowsSandboxLevel;
@@ -344,6 +343,7 @@ use self::plan_implementation::PLAN_IMPLEMENTATION_TITLE;
 mod realtime;
 use self::realtime::RealtimeConversationUiState;
 mod reasoning_shortcuts;
+mod service_tiers;
 mod side;
 mod status_surfaces;
 use self::status_surfaces::CachedProjectRootName;
@@ -761,7 +761,7 @@ pub(crate) struct ChatWidget {
     config: Config,
     raw_output_mode: bool,
     /// Runtime value resolved by core. `config.service_tier` remains the explicit user choice.
-    effective_service_tier: Option<ServiceTier>,
+    effective_service_tier: Option<String>,
     /// The unmasked collaboration mode settings (always Default mode).
     ///
     /// Masks are applied on top of this base mode to derive the effective mode.
@@ -2072,10 +2072,7 @@ impl ChatWidget {
         self.current_rollout_path = session.rollout_path.clone();
         self.current_cwd = Some(session.cwd.to_path_buf());
         self.config.cwd = session.cwd.clone();
-        self.effective_service_tier = session
-            .service_tier
-            .as_deref()
-            .and_then(ServiceTier::from_request_value);
+        self.effective_service_tier = session.service_tier.clone();
         if let Err(err) = self
             .config
             .permissions
@@ -2116,15 +2113,15 @@ impl ChatWidget {
         }
         self.refresh_model_display();
         self.refresh_status_surfaces();
-        self.sync_fast_command_enabled();
+        self.sync_service_tier_commands();
         self.sync_personality_command_enabled();
         self.sync_plugins_command_enabled();
         self.sync_goal_command_enabled();
         self.refresh_plugin_mentions();
         if display == SessionConfiguredDisplay::Normal {
             let startup_tooltip_override = self.startup_tooltip_override.take();
-            let show_fast_status =
-                self.should_show_fast_status(&model_for_header, self.effective_service_tier);
+            let show_fast_status = self
+                .should_show_fast_status(&model_for_header, self.effective_service_tier.as_deref());
             let session_info_cell = history_cell::new_session_info(
                 &self.config,
                 &model_for_header,
@@ -4893,10 +4890,7 @@ impl ChatWidget {
         let active_cell = Some(Self::placeholder_session_header_cell(&config));
 
         let current_cwd = Some(config.cwd.to_path_buf());
-        let effective_service_tier = config
-            .service_tier
-            .as_deref()
-            .and_then(ServiceTier::from_request_value);
+        let effective_service_tier = config.service_tier.clone();
         let current_terminal_info = terminal_info();
         let runtime_keymap = RuntimeKeymap::from_config(&config.tui_keymap).ok();
         let default_keymap = RuntimeKeymap::defaults();
@@ -5088,7 +5082,7 @@ impl ChatWidget {
         widget
             .bottom_pane
             .set_collaboration_modes_enabled(/*enabled*/ true);
-        widget.sync_fast_command_enabled();
+        widget.sync_service_tier_commands();
         widget.sync_personality_command_enabled();
         widget.sync_plugins_command_enabled();
         widget.sync_goal_command_enabled();
@@ -5328,6 +5322,9 @@ impl ChatWidget {
                     InputResult::Command(cmd) => {
                         self.handle_slash_command_dispatch(cmd);
                     }
+                    InputResult::ServiceTierCommand(command) => {
+                        self.handle_service_tier_command_dispatch(command);
+                    }
                     InputResult::CommandWithArgs(cmd, args, text_elements) => {
                         self.handle_slash_command_with_args_dispatch(cmd, args, text_elements);
                     }
@@ -9193,7 +9190,7 @@ impl ChatWidget {
             }
         }
         if feature == Feature::FastMode {
-            self.sync_fast_command_enabled();
+            self.sync_service_tier_commands();
         }
         if feature == Feature::Personality {
             self.sync_personality_command_enabled();
@@ -9309,28 +9306,6 @@ impl ChatWidget {
         self.config.personality = Some(personality);
     }
 
-    /// Set Fast mode in the widget's config copy.
-    pub(crate) fn set_service_tier(&mut self, service_tier: Option<ServiceTier>) {
-        self.config.service_tier =
-            service_tier.map(|service_tier| service_tier.request_value().to_string());
-        self.effective_service_tier = service_tier;
-    }
-
-    pub(crate) fn current_service_tier(&self) -> Option<ServiceTier> {
-        self.effective_service_tier
-    }
-
-    pub(crate) fn configured_service_tier(&self) -> Option<ServiceTier> {
-        self.config
-            .service_tier
-            .as_deref()
-            .and_then(ServiceTier::from_request_value)
-    }
-
-    pub(crate) fn fast_default_opt_out(&self) -> Option<bool> {
-        self.config.notices.fast_default_opt_out
-    }
-
     pub(crate) fn status_account_display(&self) -> Option<&StatusAccountDisplay> {
         self.status_account_display.as_ref()
     }
@@ -9365,26 +9340,6 @@ impl ChatWidget {
             .set_connectors_enabled(self.connectors_enabled());
     }
 
-    pub(crate) fn should_show_fast_status(
-        &self,
-        model: &str,
-        service_tier: Option<ServiceTier>,
-    ) -> bool {
-        self.model_supports_fast_mode(model)
-            && matches!(service_tier, Some(ServiceTier::Fast))
-            && self.has_chatgpt_account
-    }
-
-    fn fast_mode_enabled(&self) -> bool {
-        self.config.features.enabled(Feature::FastMode)
-    }
-
-    pub(crate) fn can_toggle_fast_mode_from_keybinding(&self) -> bool {
-        self.fast_mode_enabled()
-            && !self.is_user_turn_pending_or_running()
-            && self.bottom_pane.no_modal_or_popup_active()
-    }
-
     pub(crate) fn set_realtime_audio_device(
         &mut self,
         kind: RealtimeAudioDeviceKind,
@@ -9416,38 +9371,6 @@ impl ChatWidget {
         self.refresh_model_dependent_surfaces();
     }
 
-    fn set_service_tier_selection(&mut self, service_tier: Option<ServiceTier>) {
-        if service_tier.is_none() {
-            self.config.notices.fast_default_opt_out = Some(true);
-        }
-        self.set_service_tier(service_tier);
-        self.app_event_tx
-            .send(AppEvent::CodexOp(AppCommand::override_turn_context(
-                /*cwd*/ None,
-                /*approval_policy*/ None,
-                /*approvals_reviewer*/ None,
-                /*permission_profile*/ None,
-                /*windows_sandbox_level*/ None,
-                /*model*/ None,
-                /*effort*/ None,
-                /*summary*/ None,
-                Some(service_tier.map(|service_tier| service_tier.request_value().to_string())),
-                /*collaboration_mode*/ None,
-                /*personality*/ None,
-            )));
-        self.app_event_tx
-            .send(AppEvent::PersistServiceTierSelection { service_tier });
-    }
-
-    pub(crate) fn toggle_fast_mode_from_ui(&mut self) {
-        let next_tier = if matches!(self.current_service_tier(), Some(ServiceTier::Fast)) {
-            None
-        } else {
-            Some(ServiceTier::Fast)
-        };
-        self.set_service_tier_selection(next_tier);
-    }
-
     pub(crate) fn current_model(&self) -> &str {
         if !self.collaboration_modes_enabled() {
             return self.current_collaboration_mode.model();
@@ -9474,11 +9397,6 @@ impl ChatWidget {
             .unwrap_or_else(|| "System default".to_string())
     }
 
-    fn sync_fast_command_enabled(&mut self) {
-        self.bottom_pane
-            .set_fast_command_enabled(self.fast_mode_enabled());
-    }
-
     fn sync_personality_command_enabled(&mut self) {
         self.bottom_pane
             .set_personality_command_enabled(self.config.features.enabled(Feature::Personality));
@@ -9508,19 +9426,6 @@ impl ChatWidget {
             .unwrap_or(false)
     }
 
-    fn model_supports_fast_mode(&self, model: &str) -> bool {
-        self.model_catalog
-            .try_list_models()
-            .ok()
-            .and_then(|models| {
-                models
-                    .into_iter()
-                    .find(|preset| preset.model == model)
-                    .map(|preset| preset.supports_fast_mode())
-            })
-            .unwrap_or(false)
-    }
-
     /// Return whether the effective model currently advertises image-input support.
     ///
     /// We intentionally default to `true` when model metadata cannot be read so transient catalog
@@ -9660,6 +9565,7 @@ impl ChatWidget {
         self.session_header.set_model(effective.model());
         // Keep composer paste affordances aligned with the currently effective model.
         self.sync_image_paste_enabled();
+        self.sync_service_tier_commands();
         self.refresh_terminal_title();
     }
 
diff --git a/codex-rs/tui/src/chatwidget/service_tiers.rs b/codex-rs/tui/src/chatwidget/service_tiers.rs
new file mode 100644
index 0000000000..f23f44dd6e
--- /dev/null
+++ b/codex-rs/tui/src/chatwidget/service_tiers.rs
@@ -0,0 +1,146 @@
+//! Service-tier selection and model-catalog helpers for `ChatWidget`.
+
+use super::ChatWidget;
+use crate::app_command::AppCommand;
+use crate::app_event::AppEvent;
+use crate::bottom_pane::slash_commands::ServiceTierCommand;
+use codex_features::Feature;
+use codex_protocol::config_types::ServiceTier;
+use codex_protocol::openai_models::SPEED_TIER_FAST;
+
+impl ChatWidget {
+    pub(crate) fn set_service_tier(&mut self, service_tier: Option<String>) {
+        self.config.service_tier = service_tier.clone();
+        self.effective_service_tier = service_tier;
+        self.refresh_model_dependent_surfaces();
+    }
+
+    pub(crate) fn current_service_tier(&self) -> Option<&str> {
+        self.effective_service_tier.as_deref()
+    }
+
+    pub(crate) fn configured_service_tier(&self) -> Option<String> {
+        self.config.service_tier.clone()
+    }
+
+    pub(crate) fn fast_default_opt_out(&self) -> Option<bool> {
+        self.config.notices.fast_default_opt_out
+    }
+
+    pub(crate) fn should_show_fast_status(&self, model: &str, service_tier: Option<&str>) -> bool {
+        service_tier.is_some_and(|service_tier| {
+            service_tier == ServiceTier::Fast.request_value()
+                && self.model_supports_service_tier(model, service_tier)
+        }) && self.has_chatgpt_account
+    }
+
+    pub(super) fn fast_mode_enabled(&self) -> bool {
+        self.config.features.enabled(Feature::FastMode)
+    }
+
+    pub(crate) fn can_toggle_fast_mode_from_keybinding(&self) -> bool {
+        self.fast_mode_enabled()
+            && self.current_model_fast_service_tier().is_some()
+            && !self.is_user_turn_pending_or_running()
+            && self.bottom_pane.no_modal_or_popup_active()
+    }
+
+    pub(crate) fn toggle_fast_mode_from_ui(&mut self) {
+        let Some(fast_tier) = self.current_model_fast_service_tier() else {
+            return;
+        };
+        let next_tier = if self.current_service_tier() == Some(fast_tier.id.as_str()) {
+            None
+        } else {
+            Some(fast_tier.id)
+        };
+        self.set_service_tier_selection(next_tier);
+    }
+
+    pub(crate) fn toggle_service_tier_from_ui(&mut self, command: ServiceTierCommand) {
+        let next_tier = if self.current_service_tier() == Some(command.id.as_str()) {
+            None
+        } else {
+            Some(command.id)
+        };
+        self.set_service_tier_selection(next_tier);
+    }
+
+    pub(super) fn sync_service_tier_commands(&mut self) {
+        self.bottom_pane
+            .set_service_tier_commands_enabled(self.fast_mode_enabled());
+        self.bottom_pane
+            .set_service_tier_commands(self.current_model_service_tier_commands());
+    }
+
+    pub(super) fn current_model_service_tier_commands(&self) -> Vec<ServiceTierCommand> {
+        let model = self.current_model();
+        self.model_catalog
+            .try_list_models()
+            .ok()
+            .and_then(|models| {
+                models
+                    .into_iter()
+                    .find(|preset| preset.model == model)
+                    .map(|preset| {
+                        preset
+                            .service_tiers
+                            .into_iter()
+                            .map(|tier| ServiceTierCommand {
+                                id: tier.id,
+                                name: tier.name,
+                                description: tier.description,
+                            })
+                            .collect()
+                    })
+            })
+            .unwrap_or_default()
+    }
+
+    fn set_service_tier_selection(&mut self, service_tier: Option<String>) {
+        if service_tier.is_none() {
+            self.config.notices.fast_default_opt_out = Some(true);
+        }
+        self.set_service_tier(service_tier.clone());
+        self.app_event_tx
+            .send(AppEvent::CodexOp(AppCommand::override_turn_context(
+                /*cwd*/ None,
+                /*approval_policy*/ None,
+                /*approvals_reviewer*/ None,
+                /*permission_profile*/ None,
+                /*windows_sandbox_level*/ None,
+                /*model*/ None,
+                /*effort*/ None,
+                /*summary*/ None,
+                Some(service_tier.clone()),
+                /*collaboration_mode*/ None,
+                /*personality*/ None,
+            )));
+        self.app_event_tx
+            .send(AppEvent::PersistServiceTierSelection { service_tier });
+    }
+
+    fn model_supports_service_tier(&self, model: &str, service_tier: &str) -> bool {
+        self.model_catalog
+            .try_list_models()
+            .ok()
+            .and_then(|models| {
+                models
+                    .into_iter()
+                    .find(|preset| preset.model == model)
+                    .map(|preset| {
+                        preset
+                            .service_tiers
+                            .iter()
+                            .any(|tier| tier.id == service_tier)
+                    })
+            })
+            .unwrap_or(false)
+    }
+
+    fn current_model_fast_service_tier(&self) -> Option<ServiceTierCommand> {
+        self.current_model_service_tier_commands()
+            .into_iter()
+            .find(|tier| tier.name.eq_ignore_ascii_case(SPEED_TIER_FAST))
+    }
+}
diff --git a/codex-rs/tui/src/chatwidget/slash_dispatch.rs b/codex-rs/tui/src/chatwidget/slash_dispatch.rs
index 6d1278ea2d..cedc0e9686 100644
--- a/codex-rs/tui/src/chatwidget/slash_dispatch.rs
+++ b/codex-rs/tui/src/chatwidget/slash_dispatch.rs
@@ -9,7 +9,10 @@ use super::goal_validation::GoalObjectiveValidationSource;
 use super::*;
 use crate::app_event::ThreadGoalSetMode;
 use crate::bottom_pane::prompt_args::parse_slash_name;
-use crate::bottom_pane::slash_commands;
+use crate::bottom_pane::slash_commands::BuiltinCommandFlags;
+use crate::bottom_pane::slash_commands::ServiceTierCommand;
+use crate::bottom_pane::slash_commands::SlashCommandItem;
+use crate::bottom_pane::slash_commands::find_slash_command;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 enum SlashCommandDispatchSource {
@@ -48,6 +51,20 @@ impl ChatWidget {
         self.bottom_pane.record_pending_slash_command_history();
     }
 
+    pub(super) fn handle_service_tier_command_dispatch(&mut self, command: ServiceTierCommand) {
+        if self.active_side_conversation {
+            self.add_error_message(format!(
+                "'/{}' is unavailable in side conversations. {SIDE_SLASH_COMMAND_UNAVAILABLE_HINT}",
+                command.name
+            ));
+            self.bottom_pane.drain_pending_submission_state();
+            self.bottom_pane.record_pending_slash_command_history();
+            return;
+        }
+        self.toggle_service_tier_from_ui(command);
+        self.bottom_pane.record_pending_slash_command_history();
+    }
+
     /// Dispatch an inline slash command and record its staged local-history entry.
     ///
     /// Inline command arguments may later be prepared through the normal submission pipeline, but
@@ -184,9 +201,6 @@ impl ChatWidget {
             SlashCommand::Model => {
                 self.open_model_popup();
             }
-            SlashCommand::Fast => {
-                self.toggle_fast_mode_from_ui();
-            }
             SlashCommand::Realtime => {
                 if !self.realtime_conversation_enabled() {
                     return;
@@ -572,27 +586,6 @@ impl ChatWidget {
         } = prepared;
         let trimmed = args.trim();
         match cmd {
-            SlashCommand::Fast => {
-                match trimmed.to_ascii_lowercase().as_str() {
-                    "on" => self.set_service_tier_selection(Some(ServiceTier::Fast)),
-                    "off" => self.set_service_tier_selection(/*service_tier*/ None),
-                    "status" => {
-                        let status =
-                            if matches!(self.current_service_tier(), Some(ServiceTier::Fast)) {
-                                "on"
-                            } else {
-                                "off"
-                            };
-                        self.add_info_message(
-                            format!("Fast mode is {status}."),
-                            /*hint*/ None,
-                        );
-                    }
-                    _ => {
-                        self.add_error_message("Usage: /fast [on|off|status]".to_string());
-                    }
-                }
-            }
             SlashCommand::Ide => {
                 self.handle_ide_command_args(trimmed);
             }
@@ -813,7 +806,9 @@ impl ChatWidget {
             return QueueDrain::Stop;
         }
 
-        let Some(cmd) = slash_commands::find_builtin_command(name, self.builtin_command_flags())
+        let service_tier_commands = self.current_model_service_tier_commands();
+        let Some(command) =
+            find_slash_command(name, self.builtin_command_flags(), &service_tier_commands)
         else {
             self.add_info_message(
                 format!(
@@ -825,11 +820,19 @@ impl ChatWidget {
         };
 
         if rest.is_empty() {
-            self.dispatch_command(cmd);
-            return self.queued_command_drain_result(cmd);
+            return match command {
+                SlashCommandItem::Builtin(cmd) => {
+                    self.dispatch_command(cmd);
+                    self.queued_command_drain_result(cmd)
+                }
+                SlashCommandItem::ServiceTier(command) => {
+                    self.handle_service_tier_command_dispatch(command);
+                    QueueDrain::Continue
+                }
+            };
         }
 
-        if !cmd.supports_inline_args() {
+        if !command.supports_inline_args() {
             self.submit_user_message(UserMessage {
                 text,
                 local_images,
@@ -839,6 +842,16 @@ impl ChatWidget {
             });
             return QueueDrain::Stop;
         }
+        let SlashCommandItem::Builtin(cmd) = command else {
+            self.submit_user_message(UserMessage {
+                text,
+                local_images,
+                remote_image_urls,
+                text_elements,
+                mention_bindings,
+            });
+            return QueueDrain::Stop;
+        };
 
         let trimmed_start = rest.trim_start();
         let leading_trimmed = rest.len().saturating_sub(trimmed_start.len());
@@ -867,7 +880,7 @@ impl ChatWidget {
         self.queued_command_drain_result(cmd)
     }
 
-    fn builtin_command_flags(&self) -> slash_commands::BuiltinCommandFlags {
+    fn builtin_command_flags(&self) -> BuiltinCommandFlags {
         #[cfg(target_os = "windows")]
         let allow_elevate_sandbox = {
             let windows_sandbox_level = WindowsSandboxLevel::from_config(&self.config);
@@ -876,12 +889,12 @@ impl ChatWidget {
         #[cfg(not(target_os = "windows"))]
         let allow_elevate_sandbox = false;
 
-        slash_commands::BuiltinCommandFlags {
+        BuiltinCommandFlags {
             collaboration_modes_enabled: self.collaboration_modes_enabled(),
             connectors_enabled: self.connectors_enabled(),
             plugins_command_enabled: self.config.features.enabled(Feature::Plugins),
             goal_command_enabled: self.config.features.enabled(Feature::Goals),
-            fast_command_enabled: self.fast_mode_enabled(),
+            service_tier_commands_enabled: self.fast_mode_enabled(),
             personality_command_enabled: self.config.features.enabled(Feature::Personality),
             realtime_conversation_enabled: self.realtime_conversation_enabled(),
             audio_device_selection_enabled: self.realtime_audio_device_selection_enabled(),
@@ -895,8 +908,7 @@ impl ChatWidget {
             return QueueDrain::Stop;
         }
         match cmd {
-            SlashCommand::Fast
-            | SlashCommand::Ide
+            SlashCommand::Ide
             | SlashCommand::Status
             | SlashCommand::DebugConfig
             | SlashCommand::Ps
diff --git a/codex-rs/tui/src/chatwidget/status_surfaces.rs b/codex-rs/tui/src/chatwidget/status_surfaces.rs
index 9d4b7103d0..b316d0c5fb 100644
--- a/codex-rs/tui/src/chatwidget/status_surfaces.rs
+++ b/codex-rs/tui/src/chatwidget/status_surfaces.rs
@@ -10,6 +10,7 @@ use crate::legacy_core::config::Config;
 use crate::status::format_tokens_compact;
 use codex_app_server_protocol::AskForApproval;
 use codex_protocol::config_types::ApprovalsReviewer;
+use codex_protocol::config_types::ServiceTier;
 use codex_protocol::models::PermissionProfile;
 use codex_utils_sandbox_summary::summarize_permission_profile;
 
@@ -648,7 +649,7 @@ impl ChatWidget {
             )),
             StatusLineItem::SessionId => self.thread_id.map(|id| id.to_string()),
             StatusLineItem::FastMode => Some(
-                if matches!(self.current_service_tier(), Some(ServiceTier::Fast)) {
+                if self.current_service_tier() == Some(ServiceTier::Fast.request_value()) {
                     "Fast on".to_string()
                 } else {
                     "Fast off".to_string()
@@ -779,13 +780,18 @@ impl ChatWidget {
 
     fn model_with_reasoning_display_name(&self) -> String {
         let label = Self::status_line_reasoning_effort_label(self.effective_reasoning_effort());
-        let fast_label =
-            if self.should_show_fast_status(self.current_model(), self.current_service_tier()) {
-                " fast"
-            } else {
-                ""
-            };
-        format!("{} {label}{fast_label}", self.model_display_name())
+        let service_tier_label = self
+            .current_service_tier()
+            .and_then(|service_tier| {
+                self.current_model_service_tier_commands()
+                    .into_iter()
+                    .find(|tier| tier.id == service_tier)
+                    .map(|tier| tier.name)
+            })
+            .filter(|_| self.has_chatgpt_account)
+            .map(|tier| format!(" {tier}"))
+            .unwrap_or_default();
+        format!("{} {label}{service_tier_label}", self.model_display_name())
     }
 
     /// Computes the compact runtime status label used by word-based status items.
diff --git a/codex-rs/tui/src/chatwidget/tests/helpers.rs b/codex-rs/tui/src/chatwidget/tests/helpers.rs
index 14f856bee5..e03eda919b 100644
--- a/codex-rs/tui/src/chatwidget/tests/helpers.rs
+++ b/codex-rs/tui/src/chatwidget/tests/helpers.rs
@@ -182,10 +182,7 @@ pub(super) async fn make_chatwidget_manual(
     };
     let current_collaboration_mode = base_mode;
     let active_collaboration_mask = collaboration_modes::default_mask(model_catalog.as_ref());
-    let effective_service_tier = cfg
-        .service_tier
-        .as_deref()
-        .and_then(ServiceTier::from_request_value);
+    let effective_service_tier = cfg.service_tier.clone();
     let mut widget = ChatWidget {
         app_event_tx,
         codex_op_target: super::CodexOpTarget::Direct(op_tx),
@@ -391,8 +388,12 @@ pub(crate) fn set_chatgpt_auth(chat: &mut ChatWidget) {
 }
 
 fn test_model_info(slug: &str, priority: i32, supports_fast_mode: bool) -> ModelInfo {
-    let additional_speed_tiers = if supports_fast_mode {
-        vec![codex_protocol::openai_models::SPEED_TIER_FAST]
+    let service_tiers = if supports_fast_mode {
+        vec![json!({
+            "id": ServiceTier::Fast.request_value(),
+            "name": "fast",
+            "description": "Fastest inference with increased plan usage"
+        })]
     } else {
         Vec::new()
     };
@@ -406,7 +407,8 @@ fn test_model_info(slug: &str, priority: i32, supports_fast_mode: bool) -> Model
         "visibility": "list",
         "supported_in_api": true,
         "priority": priority,
-        "additional_speed_tiers": additional_speed_tiers,
+        "additional_speed_tiers": [],
+        "service_tiers": service_tiers,
         "availability_nux": null,
         "upgrade": null,
         "base_instructions": "base instructions",
diff --git a/codex-rs/tui/src/chatwidget/tests/slash_commands.rs b/codex-rs/tui/src/chatwidget/tests/slash_commands.rs
index 87ad226b51..dc8f2e7cb2 100644
--- a/codex-rs/tui/src/chatwidget/tests/slash_commands.rs
+++ b/codex-rs/tui/src/chatwidget/tests/slash_commands.rs
@@ -1,6 +1,15 @@
 use super::*;
+use crate::bottom_pane::slash_commands::ServiceTierCommand;
 use pretty_assertions::assert_eq;
 
+fn fast_tier_command() -> ServiceTierCommand {
+    ServiceTierCommand {
+        id: ServiceTier::Fast.request_value().to_string(),
+        name: "fast".to_string(),
+        description: "Fastest inference with increased plan usage".to_string(),
+    }
+}
+
 fn complete_turn_with_message(chat: &mut ChatWidget, turn_id: &str, message: Option<&str>) {
     if let Some(message) = message {
         complete_assistant_message(
@@ -1023,9 +1032,8 @@ async fn slash_rename_without_existing_thread_name_starts_empty() {
 #[tokio::test]
 async fn usage_error_slash_command_is_available_from_local_recall() {
     let (mut chat, mut rx, _op_rx) = make_chatwidget_manual(Some("gpt-5.3-codex")).await;
-    chat.set_feature_enabled(Feature::FastMode, /*enabled*/ true);
 
-    submit_composer_text(&mut chat, "/fast maybe");
+    submit_composer_text(&mut chat, "/raw maybe");
 
     assert_eq!(chat.bottom_pane.composer_text(), "");
 
@@ -1036,10 +1044,10 @@ async fn usage_error_slash_command_is_available_from_local_recall() {
         .collect::<Vec<_>>()
         .join("\n");
     assert!(
-        rendered.contains("Usage: /fast [on|off|status]"),
+        rendered.contains("Usage: /raw [on|off]"),
         "expected usage message, got: {rendered:?}"
     );
-    assert_eq!(recall_latest_after_clearing(&mut chat), "/fast maybe");
+    assert_eq!(recall_latest_after_clearing(&mut chat), "/raw maybe");
 }
 
 #[tokio::test]
@@ -1811,10 +1819,11 @@ async fn slash_rollout_handles_missing_path() {
 
 #[tokio::test]
 async fn fast_slash_command_updates_and_persists_local_service_tier() {
-    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(Some("gpt-5.3-codex")).await;
+    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(Some("gpt-5.4")).await;
+    set_fast_mode_test_catalog(&mut chat);
     chat.set_feature_enabled(Feature::FastMode, /*enabled*/ true);
 
-    chat.dispatch_command(SlashCommand::Fast);
+    chat.handle_service_tier_command_dispatch(fast_tier_command());
 
     let events = std::iter::from_fn(|| rx.try_recv().ok()).collect::<Vec<_>>();
     assert!(
@@ -1831,8 +1840,9 @@ async fn fast_slash_command_updates_and_persists_local_service_tier() {
         events.iter().any(|event| matches!(
             event,
             AppEvent::PersistServiceTierSelection {
-                service_tier: Some(ServiceTier::Fast),
+                service_tier: Some(service_tier),
             }
+            if service_tier == ServiceTier::Fast.request_value()
         )),
         "expected fast-mode persistence app event; events: {events:?}"
     );
@@ -1842,7 +1852,8 @@ async fn fast_slash_command_updates_and_persists_local_service_tier() {
 
 #[tokio::test]
 async fn fast_keybinding_toggle_uses_same_events_as_fast_slash_command() {
-    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(Some("gpt-5.3-codex")).await;
+    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(Some("gpt-5.4")).await;
+    set_fast_mode_test_catalog(&mut chat);
     chat.set_feature_enabled(Feature::FastMode, /*enabled*/ true);
 
     chat.toggle_fast_mode_from_ui();
@@ -1862,8 +1873,9 @@ async fn fast_keybinding_toggle_uses_same_events_as_fast_slash_command() {
         events.iter().any(|event| matches!(
             event,
             AppEvent::PersistServiceTierSelection {
-                service_tier: Some(ServiceTier::Fast),
+                service_tier: Some(service_tier),
             }
+            if service_tier == ServiceTier::Fast.request_value()
         )),
         "expected fast-mode persistence app event; events: {events:?}"
     );
@@ -1873,7 +1885,8 @@ async fn fast_keybinding_toggle_uses_same_events_as_fast_slash_command() {
 
 #[tokio::test]
 async fn fast_keybinding_toggle_requires_feature_and_idle_surface() {
-    let (mut chat, _rx, _op_rx) = make_chatwidget_manual(Some("gpt-5.3-codex")).await;
+    let (mut chat, _rx, _op_rx) = make_chatwidget_manual(Some("gpt-5.4")).await;
+    set_fast_mode_test_catalog(&mut chat);
     chat.set_feature_enabled(Feature::FastMode, /*enabled*/ false);
 
     assert!(!chat.can_toggle_fast_mode_from_keybinding());
@@ -1887,12 +1900,13 @@ async fn fast_keybinding_toggle_requires_feature_and_idle_surface() {
 
 #[tokio::test]
 async fn user_turn_carries_service_tier_after_fast_toggle() {
-    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(Some("gpt-5.3-codex")).await;
+    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(Some("gpt-5.4")).await;
     chat.thread_id = Some(ThreadId::new());
     set_chatgpt_auth(&mut chat);
+    set_fast_mode_test_catalog(&mut chat);
     chat.set_feature_enabled(Feature::FastMode, /*enabled*/ true);
 
-    chat.dispatch_command(SlashCommand::Fast);
+    chat.handle_service_tier_command_dispatch(fast_tier_command());
 
     let _events = std::iter::from_fn(|| rx.try_recv().ok()).collect::<Vec<_>>();
 
@@ -1911,13 +1925,14 @@ async fn user_turn_carries_service_tier_after_fast_toggle() {
 
 #[tokio::test]
 async fn queued_fast_slash_applies_before_next_queued_message() {
-    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(Some("gpt-5.3-codex")).await;
+    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(Some("gpt-5.4")).await;
     chat.thread_id = Some(ThreadId::new());
     set_chatgpt_auth(&mut chat);
+    set_fast_mode_test_catalog(&mut chat);
     chat.set_feature_enabled(Feature::FastMode, /*enabled*/ true);
     handle_turn_started(&mut chat, "turn-1");
 
-    queue_composer_text_with_tab(&mut chat, "/fast on");
+    queue_composer_text_with_tab(&mut chat, "/fast");
     queue_composer_text_with_tab(&mut chat, "hello after fast");
 
     complete_turn_with_message(&mut chat, "turn-1", Some("done"));
@@ -1952,15 +1967,16 @@ async fn queued_fast_slash_applies_before_next_queued_message() {
 
 #[tokio::test]
 async fn user_turn_sends_standard_override_after_fast_is_turned_off() {
-    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(Some("gpt-5.3-codex")).await;
+    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(Some("gpt-5.4")).await;
     chat.thread_id = Some(ThreadId::new());
     set_chatgpt_auth(&mut chat);
+    set_fast_mode_test_catalog(&mut chat);
     chat.set_feature_enabled(Feature::FastMode, /*enabled*/ true);
 
-    chat.dispatch_command(SlashCommand::Fast);
+    chat.handle_service_tier_command_dispatch(fast_tier_command());
     let _events = std::iter::from_fn(|| rx.try_recv().ok()).collect::<Vec<_>>();
 
-    chat.dispatch_command_with_args(SlashCommand::Fast, "off".to_string(), Vec::new());
+    chat.handle_service_tier_command_dispatch(fast_tier_command());
     let events = std::iter::from_fn(|| rx.try_recv().ok()).collect::<Vec<_>>();
     assert!(
         events.iter().any(|event| matches!(
diff --git a/codex-rs/tui/src/chatwidget/tests/status_and_layout.rs b/codex-rs/tui/src/chatwidget/tests/status_and_layout.rs
index 89bb715be5..93e3222a5e 100644
--- a/codex-rs/tui/src/chatwidget/tests/status_and_layout.rs
+++ b/codex-rs/tui/src/chatwidget/tests/status_and_layout.rs
@@ -1124,7 +1124,7 @@ async fn fast_status_indicator_requires_chatgpt_auth() {
     let (mut chat, _rx, _op_rx) = make_chatwidget_manual(Some("gpt-5.4")).await;
     set_fast_mode_test_catalog(&mut chat);
     assert!(get_available_model(&chat, "gpt-5.4").supports_fast_mode());
-    chat.set_service_tier(Some(ServiceTier::Fast));
+    chat.set_service_tier(Some(ServiceTier::Fast.request_value().to_string()));
 
     assert!(!chat.should_show_fast_status(chat.current_model(), chat.current_service_tier(),));
 
@@ -1140,7 +1140,7 @@ async fn fast_status_indicator_is_hidden_for_models_without_fast_support() {
     let (mut chat, _rx, _op_rx) = make_chatwidget_manual(Some("gpt-5.3-codex")).await;
     set_fast_mode_test_catalog(&mut chat);
     assert!(!get_available_model(&chat, "gpt-5.3-codex").supports_fast_mode());
-    chat.set_service_tier(Some(ServiceTier::Fast));
+    chat.set_service_tier(Some(ServiceTier::Fast.request_value().to_string()));
     set_chatgpt_auth(&mut chat);
     set_fast_mode_test_catalog(&mut chat);
     assert!(!get_available_model(&chat, "gpt-5.3-codex").supports_fast_mode());
@@ -1533,7 +1533,7 @@ async fn status_line_fast_mode_renders_on_and_off() {
     chat.refresh_status_line();
     assert_eq!(status_line_text(&chat), Some("Fast off".to_string()));
 
-    chat.set_service_tier(Some(ServiceTier::Fast));
+    chat.set_service_tier(Some(ServiceTier::Fast.request_value().to_string()));
     chat.refresh_status_line();
     assert_eq!(status_line_text(&chat), Some("Fast on".to_string()));
 }
@@ -1546,7 +1546,7 @@ async fn status_line_fast_mode_footer_snapshot() {
     let (mut chat, _rx, _op_rx) = make_chatwidget_manual(/*model_override*/ None).await;
     chat.show_welcome_banner = false;
     chat.config.tui_status_line = Some(vec!["fast-mode".to_string()]);
-    chat.set_service_tier(Some(ServiceTier::Fast));
+    chat.set_service_tier(Some(ServiceTier::Fast.request_value().to_string()));
     chat.refresh_status_line();
 
     let width = 80;
@@ -1573,7 +1573,7 @@ async fn status_line_model_with_reasoning_includes_fast_for_fast_capable_models(
         "current-dir".to_string(),
     ]);
     chat.set_reasoning_effort(Some(ReasoningEffortConfig::XHigh));
-    chat.set_service_tier(Some(ServiceTier::Fast));
+    chat.set_service_tier(Some(ServiceTier::Fast.request_value().to_string()));
     set_chatgpt_auth(&mut chat);
     set_fast_mode_test_catalog(&mut chat);
     assert!(get_available_model(&chat, "gpt-5.4").supports_fast_mode());
@@ -1721,7 +1721,7 @@ async fn status_line_model_with_reasoning_fast_footer_snapshot() {
         "current-dir".to_string(),
     ]);
     chat.set_reasoning_effort(Some(ReasoningEffortConfig::XHigh));
-    chat.set_service_tier(Some(ServiceTier::Fast));
+    chat.set_service_tier(Some(ServiceTier::Fast.request_value().to_string()));
     set_chatgpt_auth(&mut chat);
     set_fast_mode_test_catalog(&mut chat);
     assert!(get_available_model(&chat, "gpt-5.4").supports_fast_mode());
@@ -1755,7 +1755,7 @@ async fn status_line_model_with_reasoning_context_remaining_footer_snapshot() {
         "current-dir".to_string(),
     ]);
     chat.set_reasoning_effort(Some(ReasoningEffortConfig::XHigh));
-    chat.set_service_tier(Some(ServiceTier::Fast));
+    chat.set_service_tier(Some(ServiceTier::Fast.request_value().to_string()));
     set_chatgpt_auth(&mut chat);
     set_fast_mode_test_catalog(&mut chat);
     assert!(get_available_model(&chat, "gpt-5.4").supports_fast_mode());
diff --git a/codex-rs/tui/src/slash_command.rs b/codex-rs/tui/src/slash_command.rs
index d5e923f0e3..cce0bc38df 100644
--- a/codex-rs/tui/src/slash_command.rs
+++ b/codex-rs/tui/src/slash_command.rs
@@ -13,7 +13,6 @@ pub enum SlashCommand {
     // DO NOT ALPHA-SORT! Enum order is presentation order in the popup, so
     // more frequently used commands should be listed first.
     Model,
-    Fast,
     Ide,
     Permissions,
     Keymap,
@@ -104,9 +103,6 @@ impl SlashCommand {
             SlashCommand::MemoryDrop => "DO NOT USE",
             SlashCommand::MemoryUpdate => "DO NOT USE",
             SlashCommand::Model => "choose what model and reasoning effort to use",
-            SlashCommand::Fast => {
-                "toggle Fast mode to enable fastest inference with increased plan usage"
-            }
             SlashCommand::Ide => {
                 "include current selection, open files, and other context from your IDE"
             }
@@ -151,7 +147,6 @@ impl SlashCommand {
                 | SlashCommand::Rename
                 | SlashCommand::Plan
                 | SlashCommand::Goal
-                | SlashCommand::Fast
                 | SlashCommand::Ide
                 | SlashCommand::Keymap
                 | SlashCommand::Mcp
@@ -184,7 +179,6 @@ impl SlashCommand {
             | SlashCommand::Init
             | SlashCommand::Compact
             | SlashCommand::Model
-            | SlashCommand::Fast
             | SlashCommand::Personality
             | SlashCommand::Permissions
             | SlashCommand::Keymap