tests

codex-rs/core/src/codex.rs

@@ -59,7 +59,7 @@ use crate::client_common::ResponseEvent;
 use crate::config::Config;
 use crate::config_types::McpServerTransportConfig;
 use crate::config_types::ShellEnvironmentPolicy;
-use crate::conversation_history::ConversationHistory;
+use crate::context_manager::ContextManager;
 use crate::environment_context::EnvironmentContext;
 use crate::error::CodexErr;
 use crate::error::Result as CodexResult;
@@ -867,7 +867,7 @@ impl Session {
         turn_context: &TurnContext,
         rollout_items: &[RolloutItem],
     ) -> Vec<ResponseItem> {
-        let mut history = ConversationHistory::new();
+        let mut history = ContextManager::new();
         for item in rollout_items {
             match item {
                 RolloutItem::ResponseItem(response_item) => {
@@ -941,7 +941,7 @@ impl Session {
         state.history_snapshot()
     }
 
-    pub(crate) async fn clone_history(&self) -> ConversationHistory {
+    pub(crate) async fn clone_history(&self) -> ContextManager {
         let state = self.state.lock().await;
         state.clone_history()
     }
@@ -1524,7 +1524,7 @@ pub(crate) async fn run_task(
     // For normal turns, continue recording to the session history as before.
     let is_review_mode = turn_context.is_review_mode;
 
-    let mut review_thread_history: ConversationHistory = ConversationHistory::new();
+    let mut review_thread_history: ContextManager = ContextManager::new();
     if is_review_mode {
         // Seed review threads with environment context so the model knows the working directory.
         review_thread_history
@@ -2843,7 +2843,7 @@ mod tests {
         turn_context: &TurnContext,
     ) -> (Vec<RolloutItem>, Vec<ResponseItem>) {
         let mut rollout_items = Vec::new();
-        let mut live_history = ConversationHistory::new();
+        let mut live_history = ContextManager::new();
 
         let initial_context = session.build_initial_context(turn_context);
         for item in &initial_context {

codex-rs/core/src/context_manager/manager.rs

@@ -1,3 +1,4 @@
+use crate::context_manager::truncation::truncate_context_output;
 use codex_protocol::models::FunctionCallOutputPayload;
 use codex_protocol::models::ResponseItem;
 use codex_protocol::protocol::TokenUsage;
@@ -6,13 +7,13 @@ use tracing::error;
 
 /// Transcript of conversation history
 #[derive(Debug, Clone, Default)]
-pub(crate) struct ConversationHistory {
+pub(crate) struct ContextManager {
     /// The oldest items are at the beginning of the vector.
     items: Vec<ResponseItem>,
     token_info: Option<TokenUsageInfo>,
 }
 
-impl ConversationHistory {
+impl ContextManager {
     pub(crate) fn new() -> Self {
         Self {
             items: Vec::new(),
@@ -44,7 +45,8 @@ impl ConversationHistory {
                 continue;
             }
 
-            self.items.push(item.clone());
+            let processed = Self::process_item(&item);
+            self.items.push(processed);
         }
     }
 
@@ -76,6 +78,29 @@ impl ConversationHistory {
         self.remove_orphan_outputs();
     }
 
+    fn process_item(item: &ResponseItem) -> ResponseItem {
+        match item {
+            ResponseItem::FunctionCallOutput { call_id, output } => {
+                let truncated_content = truncate_context_output(output.content.as_str());
+                ResponseItem::FunctionCallOutput {
+                    call_id: call_id.clone(),
+                    output: FunctionCallOutputPayload {
+                        content: truncated_content,
+                        success: output.success,
+                    },
+                }
+            }
+            ResponseItem::CustomToolCallOutput { call_id, output } => {
+                let truncated = truncate_context_output(output);
+                ResponseItem::CustomToolCallOutput {
+                    call_id: call_id.clone(),
+                    output: truncated,
+                }
+            }
+            _ => item.clone(),
+        }
+    }
+
     /// Returns a clone of the contents in the transcript.
     fn contents(&self) -> Vec<ResponseItem> {
         self.items.clone()
@@ -106,7 +131,7 @@ impl ConversationHistory {
                             ResponseItem::FunctionCallOutput {
                                 call_id: call_id.clone(),
                                 output: FunctionCallOutputPayload {
-                                    content: "aborted".to_string(),
+                                    content: truncate_context_output("aborted"),
                                     success: None,
                                 },
                             },
@@ -129,7 +154,7 @@ impl ConversationHistory {
                             idx,
                             ResponseItem::CustomToolCallOutput {
                                 call_id: call_id.clone(),
-                                output: "aborted".to_string(),
+                                output: truncate_context_output("aborted"),
                             },
                         ));
                     }
@@ -153,7 +178,7 @@ impl ConversationHistory {
                                 ResponseItem::FunctionCallOutput {
                                     call_id: call_id.clone(),
                                     output: FunctionCallOutputPayload {
-                                        content: "aborted".to_string(),
+                                        content: truncate_context_output("aborted"),
                                         success: None,
                                     },
                                 },
@@ -249,7 +274,10 @@ impl ConversationHistory {
     }
 
     pub(crate) fn replace(&mut self, items: Vec<ResponseItem>) {
-        self.items = items;
+        self.items = items
+            .into_iter()
+            .map(|item| Self::process_item(&item))
+            .collect();
     }
 
     /// Removes the corresponding paired item for the provided `item`, if any.
@@ -362,6 +390,8 @@ fn is_api_message(message: &ResponseItem) -> bool {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::context_manager::truncation::TELEMETRY_PREVIEW_MAX_BYTES;
+    use crate::context_manager::truncation::TELEMETRY_PREVIEW_TRUNCATION_NOTICE;
     use codex_protocol::models::ContentItem;
     use codex_protocol::models::FunctionCallOutputPayload;
     use codex_protocol::models::LocalShellAction;
@@ -379,8 +409,8 @@ mod tests {
         }
     }
 
-    fn create_history_with_items(items: Vec<ResponseItem>) -> ConversationHistory {
-        let mut h = ConversationHistory::new();
+    fn create_history_with_items(items: Vec<ResponseItem>) -> ContextManager {
+        let mut h = ContextManager::new();
         h.record_items(items.iter());
         h
     }
@@ -397,7 +427,7 @@ mod tests {
 
     #[test]
     fn filters_non_api_messages() {
-        let mut h = ConversationHistory::default();
+        let mut h = ContextManager::default();
         // System message is not an API message; Other is ignored.
         let system = ResponseItem::Message {
             id: None,
@@ -435,6 +465,61 @@ mod tests {
         );
     }
 
+    #[test]
+    fn record_items_truncates_function_call_output() {
+        let mut h = ContextManager::new();
+        let long_content = "a".repeat(TELEMETRY_PREVIEW_MAX_BYTES + 32);
+        let item = ResponseItem::FunctionCallOutput {
+            call_id: "call-long".to_string(),
+            output: FunctionCallOutputPayload {
+                content: long_content.clone(),
+                success: Some(true),
+            },
+        };
+
+        h.record_items([&item]);
+
+        let stored = h.contents();
+        let ResponseItem::FunctionCallOutput { output, .. } = &stored[0] else {
+            panic!("expected FunctionCallOutput variant");
+        };
+        assert!(
+            output
+                .content
+                .ends_with(TELEMETRY_PREVIEW_TRUNCATION_NOTICE),
+            "truncated content should end with notice"
+        );
+        assert!(
+            output.content.len() < long_content.len(),
+            "content should shrink after truncation"
+        );
+    }
+
+    #[test]
+    fn record_items_truncates_custom_tool_output() {
+        let mut h = ContextManager::new();
+        let long_content = "b".repeat(TELEMETRY_PREVIEW_MAX_BYTES + 64);
+        let item = ResponseItem::CustomToolCallOutput {
+            call_id: "custom-long".to_string(),
+            output: long_content.clone(),
+        };
+
+        h.record_items([&item]);
+
+        let stored = h.contents();
+        let ResponseItem::CustomToolCallOutput { output, .. } = &stored[0] else {
+            panic!("expected CustomToolCallOutput variant");
+        };
+        assert!(
+            output.ends_with(TELEMETRY_PREVIEW_TRUNCATION_NOTICE),
+            "truncated output should end with notice"
+        );
+        assert!(
+            output.len() < long_content.len(),
+            "output should shrink after truncation"
+        );
+    }
+
     #[test]
     fn remove_first_item_removes_matching_output_for_function_call() {
         let items = vec![

codex-rs/core/src/context_manager/mod.rs

@@ -0,0 +1,3 @@
+mod manager;
+pub(crate) use manager::ContextManager;
+pub mod truncation;

codex-rs/core/src/context_manager/truncation.rs

@@ -0,0 +1,159 @@
+use codex_utils_string::take_bytes_at_char_boundary;
+
+#[derive(Clone, Copy)]
+pub(crate) struct TruncationConfig {
+    pub max_bytes: usize,
+    pub max_lines: usize,
+    pub truncation_notice: &'static str,
+}
+
+// Telemetry preview limits: keep log events smaller than model budgets.
+pub(crate) const TELEMETRY_PREVIEW_MAX_BYTES: usize = 2 * 1024; // 2 KiB
+pub(crate) const TELEMETRY_PREVIEW_MAX_LINES: usize = 64; // lines
+pub(crate) const TELEMETRY_PREVIEW_TRUNCATION_NOTICE: &str =
+    "[... telemetry preview truncated ...]";
+
+pub(crate) const CONTEXT_OUTPUT_TRUNCATION: TruncationConfig = TruncationConfig {
+    max_bytes: TELEMETRY_PREVIEW_MAX_BYTES,
+    max_lines: TELEMETRY_PREVIEW_MAX_LINES,
+    truncation_notice: TELEMETRY_PREVIEW_TRUNCATION_NOTICE,
+};
+
+pub(crate) fn truncate_with_config(content: &str, config: TruncationConfig) -> String {
+    let TruncationConfig {
+        max_bytes,
+        max_lines,
+        truncation_notice,
+    } = config;
+
+    let truncated_slice = take_bytes_at_char_boundary(content, max_bytes);
+    let truncated_by_bytes = truncated_slice.len() < content.len();
+
+    let mut preview = String::new();
+    let mut lines_iter = truncated_slice.lines();
+    for idx in 0..max_lines {
+        match lines_iter.next() {
+            Some(line) => {
+                if idx > 0 {
+                    preview.push('\n');
+                }
+                preview.push_str(line);
+            }
+            None => break,
+        }
+    }
+    let truncated_by_lines = lines_iter.next().is_some();
+
+    if !truncated_by_bytes && !truncated_by_lines {
+        return content.to_string();
+    }
+
+    if preview.len() < truncated_slice.len()
+        && truncated_slice
+            .as_bytes()
+            .get(preview.len())
+            .is_some_and(|byte| *byte == b'\n')
+    {
+        preview.push('\n');
+    }
+
+    if !preview.is_empty() && !preview.ends_with('\n') {
+        preview.push('\n');
+    }
+
+    preview.push_str(truncation_notice);
+    preview
+}
+
+pub(crate) fn truncate_context_output(content: &str) -> String {
+    truncate_with_config(content, CONTEXT_OUTPUT_TRUNCATION)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn truncate_with_config_returns_original_within_limits() {
+        let content = "short output";
+        let config = TruncationConfig {
+            max_bytes: 64,
+            max_lines: 5,
+            truncation_notice: "[notice]",
+        };
+        assert_eq!(truncate_with_config(content, config), content);
+    }
+
+    #[test]
+    fn truncate_with_config_truncates_by_bytes() {
+        let config = TruncationConfig {
+            max_bytes: 16,
+            max_lines: 10,
+            truncation_notice: "[notice]",
+        };
+        let content = "abcdefghijklmnopqrstuvwxyz";
+        let truncated = truncate_with_config(content, config);
+        assert!(truncated.contains("[notice]"));
+    }
+
+    #[test]
+    fn truncate_with_config_truncates_by_lines() {
+        let config = TruncationConfig {
+            max_bytes: 1024,
+            max_lines: 2,
+            truncation_notice: "[notice]",
+        };
+        let content = "l1\nl2\nl3\nl4";
+        let truncated = truncate_with_config(content, config);
+        assert!(truncated.lines().count() <= 3);
+        assert!(truncated.contains("[notice]"));
+    }
+
+    #[test]
+    fn telemetry_preview_returns_original_within_limits() {
+        let content = "short output";
+        let config = TruncationConfig {
+            max_bytes: TELEMETRY_PREVIEW_MAX_BYTES,
+            max_lines: TELEMETRY_PREVIEW_MAX_LINES,
+            truncation_notice: TELEMETRY_PREVIEW_TRUNCATION_NOTICE,
+        };
+        assert_eq!(truncate_with_config(content, config), content);
+    }
+
+    #[test]
+    fn telemetry_preview_truncates_by_bytes() {
+        let config = TruncationConfig {
+            max_bytes: TELEMETRY_PREVIEW_MAX_BYTES,
+            max_lines: TELEMETRY_PREVIEW_MAX_LINES,
+            truncation_notice: TELEMETRY_PREVIEW_TRUNCATION_NOTICE,
+        };
+        let content = "x".repeat(TELEMETRY_PREVIEW_MAX_BYTES + 8);
+        let preview = truncate_with_config(&content, config);
+
+        assert!(preview.contains(TELEMETRY_PREVIEW_TRUNCATION_NOTICE));
+        assert!(
+            preview.len()
+                <= TELEMETRY_PREVIEW_MAX_BYTES + TELEMETRY_PREVIEW_TRUNCATION_NOTICE.len() + 1
+        );
+    }
+
+    #[test]
+    fn telemetry_preview_truncates_by_lines() {
+        let config = TruncationConfig {
+            max_bytes: TELEMETRY_PREVIEW_MAX_BYTES,
+            max_lines: TELEMETRY_PREVIEW_MAX_LINES,
+            truncation_notice: TELEMETRY_PREVIEW_TRUNCATION_NOTICE,
+        };
+        let content = (0..(TELEMETRY_PREVIEW_MAX_LINES + 5))
+            .map(|idx| format!("line {idx}"))
+            .collect::<Vec<_>>()
+            .join("\n");
+
+        let preview = truncate_with_config(&content, config);
+        let lines: Vec<&str> = preview.lines().collect();
+
+        assert!(lines.len() <= TELEMETRY_PREVIEW_MAX_LINES + 1);
+        assert_eq!(lines.last(), Some(&TELEMETRY_PREVIEW_TRUNCATION_NOTICE));
+    }
+}

codex-rs/core/src/lib.rs

@@ -20,7 +20,7 @@ pub mod config_edit;
 pub mod config_loader;
 pub mod config_profile;
 pub mod config_types;
-mod conversation_history;
+mod context_manager;
 pub mod custom_prompts;
 mod environment_context;
 pub mod error;

codex-rs/core/src/response_processing.rs

@@ -1,5 +1,5 @@
 use crate::codex::Session;
-use crate::conversation_history::ConversationHistory;
+use crate::context_manager::ContextManager;
 use codex_protocol::models::FunctionCallOutputPayload;
 use codex_protocol::models::ResponseInputItem;
 use codex_protocol::models::ResponseItem;
@@ -11,7 +11,7 @@ use tracing::warn;
 pub(crate) async fn process_items(
     processed_items: Vec<crate::codex::ProcessedResponseItem>,
     is_review_mode: bool,
-    review_thread_history: &mut ConversationHistory,
+    review_thread_history: &mut ContextManager,
     sess: &Session,
 ) -> (Vec<ResponseInputItem>, Vec<ResponseItem>) {
     let mut items_to_record_in_conversation_history = Vec::<ResponseItem>::new();

codex-rs/core/src/state/session.rs

@@ -3,7 +3,7 @@
 use codex_protocol::models::ResponseItem;
 
 use crate::codex::SessionConfiguration;
-use crate::conversation_history::ConversationHistory;
+use crate::context_manager::ContextManager;
 use crate::protocol::RateLimitSnapshot;
 use crate::protocol::TokenUsage;
 use crate::protocol::TokenUsageInfo;
@@ -11,7 +11,7 @@ use crate::protocol::TokenUsageInfo;
 /// Persistent, session-scoped state previously stored directly on `Session`.
 pub(crate) struct SessionState {
     pub(crate) session_configuration: SessionConfiguration,
-    pub(crate) history: ConversationHistory,
+    pub(crate) history: ContextManager,
     pub(crate) latest_rate_limits: Option<RateLimitSnapshot>,
 }
 
@@ -20,7 +20,7 @@ impl SessionState {
     pub(crate) fn new(session_configuration: SessionConfiguration) -> Self {
         Self {
             session_configuration,
-            history: ConversationHistory::new(),
+            history: ContextManager::new(),
             latest_rate_limits: None,
         }
     }
@@ -38,7 +38,7 @@ impl SessionState {
         self.history.get_history()
     }
 
-    pub(crate) fn clone_history(&self) -> ConversationHistory {
+    pub(crate) fn clone_history(&self) -> ContextManager {
         self.history.clone()
     }
 

codex-rs/core/src/tools/context.rs

@@ -1,15 +1,11 @@
 use crate::codex::Session;
 use crate::codex::TurnContext;
-use crate::tools::TELEMETRY_PREVIEW_MAX_BYTES;
-use crate::tools::TELEMETRY_PREVIEW_MAX_LINES;
-use crate::tools::TELEMETRY_PREVIEW_TRUNCATION_NOTICE;
 use crate::turn_diff_tracker::TurnDiffTracker;
 use codex_otel::otel_event_manager::OtelEventManager;
 use codex_protocol::models::FunctionCallOutputPayload;
 use codex_protocol::models::ResponseInputItem;
 use codex_protocol::models::ShellToolCallParams;
 use codex_protocol::protocol::FileChange;
-use codex_utils_string::take_bytes_at_char_boundary;
 use mcp_types::CallToolResult;
 use std::borrow::Cow;
 use std::collections::HashMap;
@@ -76,7 +72,7 @@ pub enum ToolOutput {
 impl ToolOutput {
     pub fn log_preview(&self) -> String {
         match self {
-            ToolOutput::Function { content, .. } => telemetry_preview(content),
+            ToolOutput::Function { content, .. } => content.clone(),
             ToolOutput::Mcp { result } => format!("{result:?}"),
         }
     }
@@ -111,46 +107,6 @@ impl ToolOutput {
     }
 }
 
-fn telemetry_preview(content: &str) -> String {
-    let truncated_slice = take_bytes_at_char_boundary(content, TELEMETRY_PREVIEW_MAX_BYTES);
-    let truncated_by_bytes = truncated_slice.len() < content.len();
-
-    let mut preview = String::new();
-    let mut lines_iter = truncated_slice.lines();
-    for idx in 0..TELEMETRY_PREVIEW_MAX_LINES {
-        match lines_iter.next() {
-            Some(line) => {
-                if idx > 0 {
-                    preview.push('\n');
-                }
-                preview.push_str(line);
-            }
-            None => break,
-        }
-    }
-    let truncated_by_lines = lines_iter.next().is_some();
-
-    if !truncated_by_bytes && !truncated_by_lines {
-        return content.to_string();
-    }
-
-    if preview.len() < truncated_slice.len()
-        && truncated_slice
-            .as_bytes()
-            .get(preview.len())
-            .is_some_and(|byte| *byte == b'\n')
-    {
-        preview.push('\n');
-    }
-
-    if !preview.is_empty() && !preview.ends_with('\n') {
-        preview.push('\n');
-    }
-    preview.push_str(TELEMETRY_PREVIEW_TRUNCATION_NOTICE);
-
-    preview
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -196,38 +152,6 @@ mod tests {
             other => panic!("expected FunctionCallOutput, got {other:?}"),
         }
     }
-
-    #[test]
-    fn telemetry_preview_returns_original_within_limits() {
-        let content = "short output";
-        assert_eq!(telemetry_preview(content), content);
-    }
-
-    #[test]
-    fn telemetry_preview_truncates_by_bytes() {
-        let content = "x".repeat(TELEMETRY_PREVIEW_MAX_BYTES + 8);
-        let preview = telemetry_preview(&content);
-
-        assert!(preview.contains(TELEMETRY_PREVIEW_TRUNCATION_NOTICE));
-        assert!(
-            preview.len()
-                <= TELEMETRY_PREVIEW_MAX_BYTES + TELEMETRY_PREVIEW_TRUNCATION_NOTICE.len() + 1
-        );
-    }
-
-    #[test]
-    fn telemetry_preview_truncates_by_lines() {
-        let content = (0..(TELEMETRY_PREVIEW_MAX_LINES + 5))
-            .map(|idx| format!("line {idx}"))
-            .collect::<Vec<_>>()
-            .join("\n");
-
-        let preview = telemetry_preview(&content);
-        let lines: Vec<&str> = preview.lines().collect();
-
-        assert!(lines.len() <= TELEMETRY_PREVIEW_MAX_LINES + 1);
-        assert_eq!(lines.last(), Some(&TELEMETRY_PREVIEW_TRUNCATION_NOTICE));
-    }
 }
 
 #[derive(Clone, Debug)]

codex-rs/core/src/tools/mod.rs

@@ -22,12 +22,6 @@ pub(crate) const MODEL_FORMAT_HEAD_LINES: usize = MODEL_FORMAT_MAX_LINES / 2;
 pub(crate) const MODEL_FORMAT_TAIL_LINES: usize = MODEL_FORMAT_MAX_LINES - MODEL_FORMAT_HEAD_LINES; // 128
 pub(crate) const MODEL_FORMAT_HEAD_BYTES: usize = MODEL_FORMAT_MAX_BYTES / 2;
 
-// Telemetry preview limits: keep log events smaller than model budgets.
-pub(crate) const TELEMETRY_PREVIEW_MAX_BYTES: usize = 2 * 1024; // 2 KiB
-pub(crate) const TELEMETRY_PREVIEW_MAX_LINES: usize = 64; // lines
-pub(crate) const TELEMETRY_PREVIEW_TRUNCATION_NOTICE: &str =
-    "[... telemetry preview truncated ...]";
-
 /// Format the combined exec output for sending back to the model.
 /// Includes exit code and duration metadata; truncates large bodies safely.
 pub fn format_exec_output_for_model(exec_output: &ExecToolCallOutput) -> String {