feat(core) update Personality on turn (#9644)

## Summary Support updating Personality mid-Thread via UserTurn/OverwriteTurn. This is explicitly unused by the clients so far, to simplify PRs - app-server and tui implementations will be follow-ups. ## Testing - [x] added integration tests
2026-04-30 09:26:44 +00:00 · 2026-01-22 12:04:23 -08:00
parent 4210fb9e6c
commit 8b3521ee77
42 changed files with 604 additions and 4 deletions
--- a/codex-rs/core/tests/suite/apply_patch_cli.rs
+++ b/codex-rs/core/tests/suite/apply_patch_cli.rs
@@ -312,6 +312,7 @@ async fn apply_patch_cli_move_without_content_change_has_no_turn_diff(
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -900,6 +901,7 @@ async fn apply_patch_shell_command_heredoc_with_cd_emits_turn_diff() -> Result<(
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -979,6 +981,7 @@ async fn apply_patch_shell_command_failure_propagates_error_and_skips_diff() ->
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1128,6 +1131,7 @@ async fn apply_patch_emits_turn_diff_event_with_unified_diff(
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1190,6 +1194,7 @@ async fn apply_patch_turn_diff_for_rename_with_content_change(
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1260,6 +1265,7 @@ async fn apply_patch_aggregates_diff_across_multiple_tool_calls() -> Result<()>
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1330,6 +1336,7 @@ async fn apply_patch_aggregates_diff_preserves_success_after_failure() -> Result
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/approvals.rs
+++ b/codex-rs/core/tests/suite/approvals.rs
@@ -502,6 +502,7 @@ async fn submit_turn(
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/client.rs
+++ b/codex-rs/core/tests/suite/client.rs
@@ -907,6 +907,7 @@ async fn user_turn_collaboration_mode_overrides_model_and_effort() -> anyhow::Re
            summary: config.model_reasoning_summary,
            collaboration_mode: Some(collaboration_mode),
            final_output_json_schema: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/collaboration_instructions.rs
+++ b/codex-rs/core/tests/suite/collaboration_instructions.rs
@@ -104,6 +104,7 @@ async fn user_input_includes_collaboration_instructions_after_override() -> Resu
            effort: None,
            summary: None,
            collaboration_mode: Some(collaboration_mode),
+            personality: None,
        })
        .await?;

@@ -151,6 +152,7 @@ async fn collaboration_instructions_added_on_user_turn() -> Result<()> {
            summary: test.config.model_reasoning_summary,
            collaboration_mode: Some(collaboration_mode),
            final_output_json_schema: None,
+            personality: None,
        })
        .await?;
    wait_for_event(&test.codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
@@ -183,6 +185,7 @@ async fn override_then_user_turn_uses_updated_collaboration_instructions() -> Re
            effort: None,
            summary: None,
            collaboration_mode: Some(collaboration_mode),
+            personality: None,
        })
        .await?;

@@ -200,6 +203,7 @@ async fn override_then_user_turn_uses_updated_collaboration_instructions() -> Re
            summary: test.config.model_reasoning_summary,
            collaboration_mode: None,
            final_output_json_schema: None,
+            personality: None,
        })
        .await?;
    wait_for_event(&test.codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
@@ -234,6 +238,7 @@ async fn user_turn_overrides_collaboration_instructions_after_override() -> Resu
            effort: None,
            summary: None,
            collaboration_mode: Some(base_mode),
+            personality: None,
        })
        .await?;

@@ -251,6 +256,7 @@ async fn user_turn_overrides_collaboration_instructions_after_override() -> Resu
            summary: test.config.model_reasoning_summary,
            collaboration_mode: Some(turn_mode),
            final_output_json_schema: None,
+            personality: None,
        })
        .await?;
    wait_for_event(&test.codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
@@ -286,6 +292,7 @@ async fn collaboration_mode_update_emits_new_instruction_message() -> Result<()>
            effort: None,
            summary: None,
            collaboration_mode: Some(collab_mode_with_instructions(Some(first_text))),
+            personality: None,
        })
        .await?;

@@ -309,6 +316,7 @@ async fn collaboration_mode_update_emits_new_instruction_message() -> Result<()>
            effort: None,
            summary: None,
            collaboration_mode: Some(collab_mode_with_instructions(Some(second_text))),
+            personality: None,
        })
        .await?;

@@ -353,6 +361,7 @@ async fn collaboration_mode_update_noop_does_not_append() -> Result<()> {
            effort: None,
            summary: None,
            collaboration_mode: Some(collab_mode_with_instructions(Some(collab_text))),
+            personality: None,
        })
        .await?;

@@ -376,6 +385,7 @@ async fn collaboration_mode_update_noop_does_not_append() -> Result<()> {
            effort: None,
            summary: None,
            collaboration_mode: Some(collab_mode_with_instructions(Some(collab_text))),
+            personality: None,
        })
        .await?;

@@ -422,6 +432,7 @@ async fn resume_replays_collaboration_instructions() -> Result<()> {
            effort: None,
            summary: None,
            collaboration_mode: Some(collab_mode_with_instructions(Some(collab_text))),
+            personality: None,
        })
        .await?;

@@ -476,6 +487,7 @@ async fn empty_collaboration_instructions_are_ignored() -> Result<()> {
            effort: None,
            summary: None,
            collaboration_mode: Some(collab_mode_with_instructions(Some(""))),
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/compact.rs
+++ b/codex-rs/core/tests/suite/compact.rs
@@ -1292,6 +1292,7 @@ async fn auto_compact_runs_after_resume_when_token_usage_is_over_limit() {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await
        .unwrap();
--- a/codex-rs/core/tests/suite/exec_policy.rs
+++ b/codex-rs/core/tests/suite/exec_policy.rs
@@ -82,6 +82,7 @@ async fn execpolicy_blocks_shell_invocation() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/image_rollout.rs
+++ b/codex-rs/core/tests/suite/image_rollout.rs
@@ -128,6 +128,7 @@ async fn copy_paste_local_image_persists_rollout_request_shape() -> anyhow::Resu
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -208,6 +209,7 @@ async fn drag_drop_image_persists_rollout_request_shape() -> anyhow::Result<()>
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/json_result.rs
+++ b/codex-rs/core/tests/suite/json_result.rs
@@ -86,6 +86,7 @@ async fn codex_returns_json_result(model: String) -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/model_overrides.rs
+++ b/codex-rs/core/tests/suite/model_overrides.rs
@@ -41,6 +41,7 @@ async fn override_turn_context_does_not_persist_when_config_exists() {
            effort: Some(Some(ReasoningEffort::High)),
            summary: None,
            collaboration_mode: None,
+            personality: None,
        })
        .await
        .expect("submit override");
@@ -84,6 +85,7 @@ async fn override_turn_context_does_not_create_config_file() {
            effort: Some(Some(ReasoningEffort::Medium)),
            summary: None,
            collaboration_mode: None,
+            personality: None,
        })
        .await
        .expect("submit override");
--- a/codex-rs/core/tests/suite/models_cache_ttl.rs
+++ b/codex-rs/core/tests/suite/models_cache_ttl.rs
@@ -99,6 +99,7 @@ async fn renews_cache_ttl_on_matching_models_etag() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/models_etag_responses.rs
+++ b/codex-rs/core/tests/suite/models_etag_responses.rs
@@ -110,6 +110,7 @@ async fn refresh_models_on_models_etag_mismatch_and_avoid_duplicate_models_fetch
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/override_updates.rs
+++ b/codex-rs/core/tests/suite/override_updates.rs
@@ -118,6 +118,7 @@ async fn override_turn_context_records_permissions_update() -> Result<()> {
            effort: None,
            summary: None,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -160,6 +161,7 @@ async fn override_turn_context_records_environment_update() -> Result<()> {
            effort: None,
            summary: None,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -196,6 +198,7 @@ async fn override_turn_context_records_collaboration_update() -> Result<()> {
            effort: None,
            summary: None,
            collaboration_mode: Some(collaboration_mode),
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/permissions_messages.rs
+++ b/codex-rs/core/tests/suite/permissions_messages.rs
@@ -110,6 +110,7 @@ async fn permissions_message_added_on_override_change() -> Result<()> {
            effort: None,
            summary: None,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -226,6 +227,7 @@ async fn resume_replays_permissions_messages() -> Result<()> {
            effort: None,
            summary: None,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -303,6 +305,7 @@ async fn resume_and_fork_append_permissions_messages() -> Result<()> {
            effort: None,
            summary: None,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/personality.rs
+++ b/codex-rs/core/tests/suite/personality.rs
@@ -1,8 +1,49 @@
 use codex_core::config::types::Personality;
+use codex_core::features::Feature;
 use codex_core::models_manager::manager::ModelsManager;
+use codex_core::models_manager::manager::RefreshStrategy;
+use codex_core::protocol::AskForApproval;
+use codex_core::protocol::EventMsg;
+use codex_core::protocol::Op;
+use codex_core::protocol::SandboxPolicy;
+use codex_protocol::config_types::ReasoningSummary;
+use codex_protocol::openai_models::ConfigShellToolType;
+use codex_protocol::openai_models::ModelInfo;
+use codex_protocol::openai_models::ModelInstructionsTemplate;
+use codex_protocol::openai_models::ModelVisibility;
+use codex_protocol::openai_models::ModelsResponse;
+use codex_protocol::openai_models::PersonalityMessages;
+use codex_protocol::openai_models::ReasoningEffort;
+use codex_protocol::openai_models::ReasoningEffortPreset;
+use codex_protocol::openai_models::TruncationPolicyConfig;
+use codex_protocol::user_input::UserInput;
 use core_test_support::load_default_config_for_test;
+use core_test_support::responses::ev_completed;
+use core_test_support::responses::ev_response_created;
+use core_test_support::responses::mount_models_once;
+use core_test_support::responses::mount_sse_once;
+use core_test_support::responses::mount_sse_sequence;
+use core_test_support::responses::sse;
+use core_test_support::responses::start_mock_server;
+use core_test_support::skip_if_no_network;
+use core_test_support::test_codex::test_codex;
+use core_test_support::wait_for_event;
 use pretty_assertions::assert_eq;
+use std::collections::BTreeMap;
+use std::sync::Arc;
 use tempfile::TempDir;
+use tokio::time::Duration;
+use tokio::time::Instant;
+use tokio::time::sleep;
+use wiremock::BodyPrintLimit;
+use wiremock::MockServer;
+
+const LOCAL_FRIENDLY_TEMPLATE: &str =
+    "You optimize for team morale and being a supportive teammate as much as code quality.";
+
+fn sse_completed(id: &str) -> String {
+    sse(vec![ev_response_created(id), ev_completed(id)])
+}

 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn model_personality_does_not_mutate_base_instructions_without_template() {
@@ -32,3 +73,362 @@ async fn base_instructions_override_disables_personality_template() {
        "override instructions"
    );
 }
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn user_turn_personality_none_does_not_add_update_message() -> anyhow::Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let resp_mock = mount_sse_once(&server, sse_completed("resp-1")).await;
+    let mut builder = test_codex().with_model("gpt-5.2-codex");
+    let test = builder.build(&server).await?;
+
+    test.codex
+        .submit(Op::UserTurn {
+            items: vec![UserInput::Text {
+                text: "hello".into(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            cwd: test.cwd_path().to_path_buf(),
+            approval_policy: test.config.approval_policy.value(),
+            sandbox_policy: SandboxPolicy::ReadOnly,
+            model: test.session_configured.model.clone(),
+            effort: test.config.model_reasoning_effort,
+            summary: ReasoningSummary::Auto,
+            collaboration_mode: None,
+            personality: None,
+        })
+        .await?;
+
+    wait_for_event(&test.codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
+
+    let request = resp_mock.single_request();
+    let developer_texts = request.message_input_texts("developer");
+    assert!(
+        !developer_texts
+            .iter()
+            .any(|text| text.contains("<personality_spec>")),
+        "did not expect a personality update message when personality is None"
+    );
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn config_personality_some_sets_instructions_template() -> anyhow::Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let resp_mock = mount_sse_once(&server, sse_completed("resp-1")).await;
+    let mut builder = test_codex()
+        .with_model("gpt-5.2-codex")
+        .with_config(|config| {
+            config.model_personality = Some(Personality::Friendly);
+            config.features.disable(Feature::RemoteModels);
+        });
+    let test = builder.build(&server).await?;
+
+    test.codex
+        .submit(Op::UserTurn {
+            items: vec![UserInput::Text {
+                text: "hello".into(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            cwd: test.cwd_path().to_path_buf(),
+            approval_policy: test.config.approval_policy.value(),
+            sandbox_policy: SandboxPolicy::ReadOnly,
+            model: test.session_configured.model.clone(),
+            effort: test.config.model_reasoning_effort,
+            summary: ReasoningSummary::Auto,
+            collaboration_mode: None,
+            personality: None,
+        })
+        .await?;
+
+    wait_for_event(&test.codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
+
+    let request = resp_mock.single_request();
+    let instructions_text = request.instructions_text();
+
+    assert!(
+        instructions_text.contains(LOCAL_FRIENDLY_TEMPLATE),
+        "expected personality update to include the local friendly template, got: {instructions_text:?}"
+    );
+
+    let developer_texts = request.message_input_texts("developer");
+    for text in developer_texts {
+        assert!(
+            !text.contains("<personality_spec>"),
+            "expected no personality update message in developer input"
+        );
+    }
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn user_turn_personality_some_adds_update_message() -> anyhow::Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let resp_mock = mount_sse_sequence(
+        &server,
+        vec![sse_completed("resp-1"), sse_completed("resp-2")],
+    )
+    .await;
+    let mut builder = test_codex()
+        .with_model("gpt-5.2-codex")
+        .with_config(|config| {
+            config.features.disable(Feature::RemoteModels);
+        });
+    let test = builder.build(&server).await?;
+
+    test.codex
+        .submit(Op::UserTurn {
+            items: vec![UserInput::Text {
+                text: "hello".into(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            cwd: test.cwd_path().to_path_buf(),
+            approval_policy: test.config.approval_policy.value(),
+            sandbox_policy: SandboxPolicy::ReadOnly,
+            model: test.session_configured.model.clone(),
+            effort: test.config.model_reasoning_effort,
+            summary: ReasoningSummary::Auto,
+            collaboration_mode: None,
+            personality: None,
+        })
+        .await?;
+
+    wait_for_event(&test.codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
+
+    test.codex
+        .submit(Op::OverrideTurnContext {
+            cwd: None,
+            approval_policy: None,
+            sandbox_policy: None,
+            model: None,
+            effort: None,
+            summary: None,
+            collaboration_mode: None,
+            personality: Some(Personality::Friendly),
+        })
+        .await?;
+
+    test.codex
+        .submit(Op::UserTurn {
+            items: vec![UserInput::Text {
+                text: "hello".into(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            cwd: test.cwd_path().to_path_buf(),
+            approval_policy: test.config.approval_policy.value(),
+            sandbox_policy: SandboxPolicy::ReadOnly,
+            model: test.session_configured.model.clone(),
+            effort: test.config.model_reasoning_effort,
+            summary: ReasoningSummary::Auto,
+            collaboration_mode: None,
+            personality: None,
+        })
+        .await?;
+
+    wait_for_event(&test.codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
+
+    let requests = resp_mock.requests();
+    assert_eq!(requests.len(), 2, "expected two requests");
+    let request = requests
+        .last()
+        .expect("expected personality update request");
+
+    let developer_texts = request.message_input_texts("developer");
+    let personality_text = developer_texts
+        .iter()
+        .find(|text| text.contains("<personality_spec>"))
+        .expect("expected personality update message in developer input");
+
+    assert!(
+        personality_text.contains("The user has requested a new communication style."),
+        "expected personality update preamble, got {personality_text:?}"
+    );
+    assert!(
+        personality_text.contains(LOCAL_FRIENDLY_TEMPLATE),
+        "expected personality update to include the local friendly template, got: {personality_text:?}"
+    );
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn user_turn_personality_remote_model_template_includes_update_message() -> anyhow::Result<()>
+{
+    skip_if_no_network!(Ok(()));
+
+    let server = MockServer::builder()
+        .body_print_limit(BodyPrintLimit::Limited(80_000))
+        .start()
+        .await;
+
+    let remote_slug = "codex-remote-personality";
+    let remote_personality_message = "Friendly from remote template";
+    let remote_model = ModelInfo {
+        slug: remote_slug.to_string(),
+        display_name: "Remote personality test".to_string(),
+        description: Some("Remote model with personality template".to_string()),
+        default_reasoning_level: Some(ReasoningEffort::Medium),
+        supported_reasoning_levels: vec![ReasoningEffortPreset {
+            effort: ReasoningEffort::Medium,
+            description: ReasoningEffort::Medium.to_string(),
+        }],
+        shell_type: ConfigShellToolType::UnifiedExec,
+        visibility: ModelVisibility::List,
+        supported_in_api: true,
+        priority: 1,
+        upgrade: None,
+        base_instructions: "base instructions".to_string(),
+        model_instructions_template: Some(ModelInstructionsTemplate {
+            template: "Base instructions\n{{ personality_message }}\n".to_string(),
+            personality_messages: Some(PersonalityMessages(BTreeMap::from([(
+                Personality::Friendly,
+                remote_personality_message.to_string(),
+            )]))),
+        }),
+        supports_reasoning_summaries: false,
+        support_verbosity: false,
+        default_verbosity: None,
+        apply_patch_tool_type: None,
+        truncation_policy: TruncationPolicyConfig::bytes(10_000),
+        supports_parallel_tool_calls: false,
+        context_window: Some(128_000),
+        auto_compact_token_limit: None,
+        effective_context_window_percent: 95,
+        experimental_supported_tools: Vec::new(),
+    };
+
+    let _models_mock = mount_models_once(
+        &server,
+        ModelsResponse {
+            models: vec![remote_model],
+        },
+    )
+    .await;
+
+    let resp_mock = mount_sse_sequence(
+        &server,
+        vec![sse_completed("resp-1"), sse_completed("resp-2")],
+    )
+    .await;
+
+    let mut builder = test_codex()
+        .with_auth(codex_core::CodexAuth::create_dummy_chatgpt_auth_for_testing())
+        .with_config(|config| {
+            config.features.enable(Feature::RemoteModels);
+            config.model = Some("gpt-5.2-codex".to_string());
+        });
+    let test = builder.build(&server).await?;
+
+    wait_for_model_available(
+        &test.thread_manager.get_models_manager(),
+        remote_slug,
+        &test.config,
+    )
+    .await;
+
+    test.codex
+        .submit(Op::UserTurn {
+            items: vec![UserInput::Text {
+                text: "hello".into(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            cwd: test.cwd_path().to_path_buf(),
+            approval_policy: AskForApproval::Never,
+            sandbox_policy: SandboxPolicy::ReadOnly,
+            model: test.session_configured.model.clone(),
+            effort: test.config.model_reasoning_effort,
+            summary: ReasoningSummary::Auto,
+            collaboration_mode: None,
+            personality: None,
+        })
+        .await?;
+
+    wait_for_event(&test.codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
+
+    test.codex
+        .submit(Op::OverrideTurnContext {
+            cwd: None,
+            approval_policy: None,
+            sandbox_policy: None,
+            model: Some(remote_slug.to_string()),
+            effort: None,
+            summary: None,
+            collaboration_mode: None,
+            personality: Some(Personality::Friendly),
+        })
+        .await?;
+
+    test.codex
+        .submit(Op::UserTurn {
+            items: vec![UserInput::Text {
+                text: "hello".into(),
+                text_elements: Vec::new(),
+            }],
+            final_output_json_schema: None,
+            cwd: test.cwd_path().to_path_buf(),
+            approval_policy: AskForApproval::Never,
+            sandbox_policy: SandboxPolicy::ReadOnly,
+            model: remote_slug.to_string(),
+            effort: test.config.model_reasoning_effort,
+            summary: ReasoningSummary::Auto,
+            collaboration_mode: None,
+            personality: None,
+        })
+        .await?;
+
+    wait_for_event(&test.codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
+
+    let requests = resp_mock.requests();
+    assert_eq!(requests.len(), 2, "expected two requests");
+    let request = requests
+        .last()
+        .expect("expected personality update request");
+    let developer_texts = request.message_input_texts("developer");
+    let personality_text = developer_texts
+        .iter()
+        .find(|text| text.contains("<personality_spec>"))
+        .expect("expected personality update message in developer input");
+
+    assert!(
+        personality_text.contains("The user has requested a new communication style."),
+        "expected personality update preamble, got {personality_text:?}"
+    );
+    assert!(
+        personality_text.contains(remote_personality_message),
+        "expected personality update to include remote template, got: {personality_text:?}"
+    );
+
+    Ok(())
+}
+
+async fn wait_for_model_available(
+    manager: &Arc<ModelsManager>,
+    slug: &str,
+    config: &codex_core::config::Config,
+) {
+    let deadline = Instant::now() + Duration::from_secs(2);
+    loop {
+        let models = manager
+            .list_models(config, RefreshStrategy::OnlineIfUncached)
+            .await;
+        if models.iter().any(|model| model.model == slug) {
+            return;
+        }
+        if Instant::now() >= deadline {
+            panic!("timed out waiting for the remote model {slug} to appear");
+        }
+        sleep(Duration::from_millis(25)).await;
+    }
+}
--- a/codex-rs/core/tests/suite/prompt_caching.rs
+++ b/codex-rs/core/tests/suite/prompt_caching.rs
@@ -353,6 +353,7 @@ async fn overrides_turn_context_but_keeps_cached_prefix_and_key_constant() -> an
            effort: Some(Some(ReasoningEffort::High)),
            summary: Some(ReasoningSummary::Detailed),
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -426,6 +427,7 @@ async fn override_before_first_turn_emits_environment_context() -> anyhow::Resul
            effort: Some(Some(ReasoningEffort::Low)),
            summary: None,
            collaboration_mode: Some(collaboration_mode),
+            personality: None,
        })
        .await?;

@@ -583,6 +585,7 @@ async fn per_turn_overrides_keep_cached_prefix_and_key_constant() -> anyhow::Res
            summary: ReasoningSummary::Detailed,
            collaboration_mode: None,
            final_output_json_schema: None,
+            personality: None,
        })
        .await?;
    wait_for_event(&codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
@@ -677,6 +680,7 @@ async fn send_user_turn_with_no_changes_does_not_send_environment_context() -> a
            summary: default_summary,
            collaboration_mode: None,
            final_output_json_schema: None,
+            personality: None,
        })
        .await?;
    wait_for_event(&codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
@@ -695,6 +699,7 @@ async fn send_user_turn_with_no_changes_does_not_send_environment_context() -> a
            summary: default_summary,
            collaboration_mode: None,
            final_output_json_schema: None,
+            personality: None,
        })
        .await?;
    wait_for_event(&codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
@@ -775,6 +780,7 @@ async fn send_user_turn_with_changes_sends_environment_context() -> anyhow::Resu
            summary: default_summary,
            collaboration_mode: None,
            final_output_json_schema: None,
+            personality: None,
        })
        .await?;
    wait_for_event(&codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
@@ -793,6 +799,7 @@ async fn send_user_turn_with_changes_sends_environment_context() -> anyhow::Resu
            summary: ReasoningSummary::Detailed,
            collaboration_mode: None,
            final_output_json_schema: None,
+            personality: None,
        })
        .await?;
    wait_for_event(&codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
--- a/codex-rs/core/tests/suite/remote_models.rs
+++ b/codex-rs/core/tests/suite/remote_models.rs
@@ -142,6 +142,7 @@ async fn remote_models_remote_model_uses_unified_exec() -> Result<()> {
            effort: None,
            summary: None,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -178,6 +179,7 @@ async fn remote_models_remote_model_uses_unified_exec() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -369,6 +371,7 @@ async fn remote_models_apply_remote_base_instructions() -> Result<()> {
            effort: None,
            summary: None,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -386,6 +389,7 @@ async fn remote_models_apply_remote_base_instructions() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/request_user_input.rs
+++ b/codex-rs/core/tests/suite/request_user_input.rs
@@ -137,6 +137,7 @@ async fn request_user_input_round_trip_resolves_pending() -> anyhow::Result<()>
                reasoning_effort: None,
                developer_instructions: None,
            })),
+            personality: None,
        })
        .await?;

@@ -249,6 +250,7 @@ where
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: Some(collaboration_mode),
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/resume_warning.rs
+++ b/codex-rs/core/tests/suite/resume_warning.rs
@@ -26,6 +26,7 @@ fn resume_history(
        approval_policy: config.approval_policy.value(),
        sandbox_policy: config.sandbox_policy.get().clone(),
        model: previous_model.to_string(),
+        personality: None,
        collaboration_mode: None,
        effort: config.model_reasoning_effort,
        summary: config.model_reasoning_summary,
--- a/codex-rs/core/tests/suite/review.rs
+++ b/codex-rs/core/tests/suite/review.rs
@@ -822,6 +822,7 @@ async fn review_uses_overridden_cwd_for_base_branch_merge_base() {
            effort: None,
            summary: None,
            collaboration_mode: None,
+            personality: None,
        })
        .await
        .unwrap();
--- a/codex-rs/core/tests/suite/rmcp_client.rs
+++ b/codex-rs/core/tests/suite/rmcp_client.rs
@@ -119,6 +119,7 @@ async fn stdio_server_round_trip() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -258,6 +259,7 @@ async fn stdio_image_responses_round_trip() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -455,6 +457,7 @@ async fn stdio_image_completions_round_trip() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -600,6 +603,7 @@ async fn stdio_server_propagates_whitelisted_env_vars() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -756,6 +760,7 @@ async fn streamable_http_tool_call_round_trip() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -944,6 +949,7 @@ async fn streamable_http_with_oauth_round_trip() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/shell_snapshot.rs
+++ b/codex-rs/core/tests/suite/shell_snapshot.rs
@@ -101,6 +101,7 @@ async fn run_snapshot_command(command: &str) -> Result<SnapshotRun> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -174,6 +175,7 @@ async fn run_shell_command_snapshot(command: &str) -> Result<SnapshotRun> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -308,6 +310,7 @@ async fn shell_command_snapshot_still_intercepts_apply_patch() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/skills.rs
+++ b/codex-rs/core/tests/suite/skills.rs
@@ -79,6 +79,7 @@ async fn user_turn_includes_skill_instructions() -> Result<()> {
            effort: None,
            summary: codex_protocol::config_types::ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/tool_harness.rs
+++ b/codex-rs/core/tests/suite/tool_harness.rs
@@ -91,6 +91,7 @@ async fn shell_tool_executes_command_and_streams_output() -> anyhow::Result<()>
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -159,6 +160,7 @@ async fn update_plan_tool_emits_plan_update_event() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -237,6 +239,7 @@ async fn update_plan_tool_rejects_malformed_payload() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -327,6 +330,7 @@ async fn apply_patch_tool_executes_and_emits_patch_events() -> anyhow::Result<()
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -425,6 +429,7 @@ async fn apply_patch_reports_parse_diagnostics() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/tool_parallelism.rs
+++ b/codex-rs/core/tests/suite/tool_parallelism.rs
@@ -48,6 +48,7 @@ async fn run_turn(test: &TestCodex, prompt: &str) -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -365,6 +366,7 @@ async fn shell_tools_start_before_response_completed_when_stream_delayed() -> an
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/truncation.rs
+++ b/codex-rs/core/tests/suite/truncation.rs
@@ -548,6 +548,7 @@ async fn mcp_image_output_preserves_image_and_no_text_summary() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/unified_exec.rs
+++ b/codex-rs/core/tests/suite/unified_exec.rs
@@ -210,6 +210,7 @@ async fn unified_exec_intercepts_apply_patch_exec_command() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -338,6 +339,7 @@ async fn unified_exec_emits_exec_command_begin_event() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -415,6 +417,7 @@ async fn unified_exec_resolves_relative_workdir() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -495,6 +498,7 @@ async fn unified_exec_respects_workdir_override() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -587,6 +591,7 @@ async fn unified_exec_emits_exec_command_end_event() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -661,6 +666,7 @@ async fn unified_exec_emits_output_delta_for_exec_command() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -736,6 +742,7 @@ async fn unified_exec_full_lifecycle_with_background_end_event() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -865,6 +872,7 @@ async fn unified_exec_emits_terminal_interaction_for_write_stdin() -> Result<()>
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1001,6 +1009,7 @@ async fn unified_exec_terminal_interaction_captures_delayed_output() -> Result<(
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1160,6 +1169,7 @@ async fn unified_exec_emits_one_begin_and_one_end_event() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1257,6 +1267,7 @@ async fn exec_command_reports_chunk_and_exit_metadata() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1374,6 +1385,7 @@ async fn unified_exec_defaults_to_pipe() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1463,6 +1475,7 @@ async fn unified_exec_can_enable_tty() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1543,6 +1556,7 @@ async fn unified_exec_respects_early_exit_notifications() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1673,6 +1687,7 @@ async fn write_stdin_returns_exit_metadata_and_clears_session() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1840,6 +1855,7 @@ async fn unified_exec_emits_end_event_when_session_dies_via_stdin() -> Result<()
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -1916,6 +1932,7 @@ async fn unified_exec_closes_long_running_session_at_turn_end() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -2037,6 +2054,7 @@ async fn unified_exec_reuses_session_via_stdin() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -2171,6 +2189,7 @@ PY
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;
    // This is a worst case scenario for the truncate logic.
@@ -2284,6 +2303,7 @@ async fn unified_exec_timeout_and_followup_poll() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -2379,6 +2399,7 @@ PY
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -2460,6 +2481,7 @@ async fn unified_exec_runs_under_sandbox() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -2563,6 +2585,7 @@ async fn unified_exec_python_prompt_under_seatbelt() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -2657,6 +2680,7 @@ async fn unified_exec_runs_on_all_platforms() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -2791,6 +2815,7 @@ async fn unified_exec_prunes_exited_sessions_first() -> Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

--- a/codex-rs/core/tests/suite/view_image.rs
+++ b/codex-rs/core/tests/suite/view_image.rs
@@ -89,6 +89,7 @@ async fn user_turn_with_local_image_attaches_image() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -182,6 +183,7 @@ async fn view_image_tool_attaches_local_image() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -314,6 +316,7 @@ async fn view_image_tool_errors_when_path_is_directory() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -388,6 +391,7 @@ async fn view_image_tool_placeholder_for_non_image_files() -> anyhow::Result<()>
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -481,6 +485,7 @@ async fn view_image_tool_errors_when_file_missing() -> anyhow::Result<()> {
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;

@@ -563,6 +568,7 @@ async fn replaces_invalid_local_image_after_bad_request() -> anyhow::Result<()>
            effort: None,
            summary: ReasoningSummary::Auto,
            collaboration_mode: None,
+            personality: None,
        })
        .await?;