refactor Conversation history file into its own directory (#6229)

This is just a refactor of `conversation_history` file by breaking it up
into multiple smaller ones with helper. This refactor will help us move
more functionality related to context management here. in a clean way.

codex-rs/core/src/codex.rs

@@ -58,7 +58,7 @@ 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;
@@ -945,7 +945,7 @@ 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) => {
@@ -1032,7 +1032,7 @@ impl Session {
         }
     }
 
-    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()
     }
@@ -2834,7 +2834,7 @@ 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/history.rs

@@ -0,0 +1,174 @@
+use codex_protocol::models::FunctionCallOutputPayload;
+use codex_protocol::models::ResponseItem;
+use codex_protocol::protocol::TokenUsage;
+use codex_protocol::protocol::TokenUsageInfo;
+use std::ops::Deref;
+
+use crate::context_manager::normalize;
+use crate::context_manager::truncate::format_output_for_model_body;
+use crate::context_manager::truncate::globally_truncate_function_output_items;
+
+/// Transcript of conversation history
+#[derive(Debug, Clone, Default)]
+pub(crate) struct ContextManager {
+    /// The oldest items are at the beginning of the vector.
+    items: Vec<ResponseItem>,
+    token_info: Option<TokenUsageInfo>,
+}
+
+impl ContextManager {
+    pub(crate) fn new() -> Self {
+        Self {
+            items: Vec::new(),
+            token_info: TokenUsageInfo::new_or_append(&None, &None, None),
+        }
+    }
+
+    pub(crate) fn token_info(&self) -> Option<TokenUsageInfo> {
+        self.token_info.clone()
+    }
+
+    pub(crate) fn set_token_usage_full(&mut self, context_window: i64) {
+        match &mut self.token_info {
+            Some(info) => info.fill_to_context_window(context_window),
+            None => {
+                self.token_info = Some(TokenUsageInfo::full_context_window(context_window));
+            }
+        }
+    }
+
+    /// `items` is ordered from oldest to newest.
+    pub(crate) fn record_items<I>(&mut self, items: I)
+    where
+        I: IntoIterator,
+        I::Item: std::ops::Deref<Target = ResponseItem>,
+    {
+        for item in items {
+            let item_ref = item.deref();
+            let is_ghost_snapshot = matches!(item_ref, ResponseItem::GhostSnapshot { .. });
+            if !is_api_message(item_ref) && !is_ghost_snapshot {
+                continue;
+            }
+
+            let processed = Self::process_item(&item);
+            self.items.push(processed);
+        }
+    }
+
+    pub(crate) fn get_history(&mut self) -> Vec<ResponseItem> {
+        self.normalize_history();
+        self.contents()
+    }
+
+    // Returns the history prepared for sending to the model.
+    // With extra response items filtered out and GhostCommits removed.
+    pub(crate) fn get_history_for_prompt(&mut self) -> Vec<ResponseItem> {
+        let mut history = self.get_history();
+        Self::remove_ghost_snapshots(&mut history);
+        history
+    }
+
+    pub(crate) fn remove_first_item(&mut self) {
+        if !self.items.is_empty() {
+            // Remove the oldest item (front of the list). Items are ordered from
+            // oldest → newest, so index 0 is the first entry recorded.
+            let removed = self.items.remove(0);
+            // If the removed item participates in a call/output pair, also remove
+            // its corresponding counterpart to keep the invariants intact without
+            // running a full normalization pass.
+            normalize::remove_corresponding_for(&mut self.items, &removed);
+        }
+    }
+
+    pub(crate) fn replace(&mut self, items: Vec<ResponseItem>) {
+        self.items = items;
+    }
+
+    pub(crate) fn update_token_info(
+        &mut self,
+        usage: &TokenUsage,
+        model_context_window: Option<i64>,
+    ) {
+        self.token_info = TokenUsageInfo::new_or_append(
+            &self.token_info,
+            &Some(usage.clone()),
+            model_context_window,
+        );
+    }
+
+    /// This function enforces a couple of invariants on the in-memory history:
+    /// 1. every call (function/custom) has a corresponding output entry
+    /// 2. every output has a corresponding call entry
+    fn normalize_history(&mut self) {
+        // all function/tool calls must have a corresponding output
+        normalize::ensure_call_outputs_present(&mut self.items);
+
+        // all outputs must have a corresponding function/tool call
+        normalize::remove_orphan_outputs(&mut self.items);
+    }
+
+    /// Returns a clone of the contents in the transcript.
+    fn contents(&self) -> Vec<ResponseItem> {
+        self.items.clone()
+    }
+
+    fn remove_ghost_snapshots(items: &mut Vec<ResponseItem>) {
+        items.retain(|item| !matches!(item, ResponseItem::GhostSnapshot { .. }));
+    }
+
+    fn process_item(item: &ResponseItem) -> ResponseItem {
+        match item {
+            ResponseItem::FunctionCallOutput { call_id, output } => {
+                let truncated = format_output_for_model_body(output.content.as_str());
+                let truncated_items = output
+                    .content_items
+                    .as_ref()
+                    .map(|items| globally_truncate_function_output_items(items));
+                ResponseItem::FunctionCallOutput {
+                    call_id: call_id.clone(),
+                    output: FunctionCallOutputPayload {
+                        content: truncated,
+                        content_items: truncated_items,
+                        success: output.success,
+                    },
+                }
+            }
+            ResponseItem::CustomToolCallOutput { call_id, output } => {
+                let truncated = format_output_for_model_body(output);
+                ResponseItem::CustomToolCallOutput {
+                    call_id: call_id.clone(),
+                    output: truncated,
+                }
+            }
+            ResponseItem::Message { .. }
+            | ResponseItem::Reasoning { .. }
+            | ResponseItem::LocalShellCall { .. }
+            | ResponseItem::FunctionCall { .. }
+            | ResponseItem::WebSearchCall { .. }
+            | ResponseItem::CustomToolCall { .. }
+            | ResponseItem::GhostSnapshot { .. }
+            | ResponseItem::Other => item.clone(),
+        }
+    }
+}
+
+/// API messages include every non-system item (user/assistant messages, reasoning,
+/// tool calls, tool outputs, shell calls, and web-search calls).
+fn is_api_message(message: &ResponseItem) -> bool {
+    match message {
+        ResponseItem::Message { role, .. } => role.as_str() != "system",
+        ResponseItem::FunctionCallOutput { .. }
+        | ResponseItem::FunctionCall { .. }
+        | ResponseItem::CustomToolCall { .. }
+        | ResponseItem::CustomToolCallOutput { .. }
+        | ResponseItem::LocalShellCall { .. }
+        | ResponseItem::Reasoning { .. }
+        | ResponseItem::WebSearchCall { .. } => true,
+        ResponseItem::GhostSnapshot { .. } => false,
+        ResponseItem::Other => false,
+    }
+}
+
+#[cfg(test)]
+#[path = "history_tests.rs"]
+mod tests;

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

@@ -0,0 +1,841 @@
+use super::*;
+use crate::context_manager::truncate;
+use codex_git::GhostCommit;
+use codex_protocol::models::ContentItem;
+use codex_protocol::models::FunctionCallOutputContentItem;
+use codex_protocol::models::FunctionCallOutputPayload;
+use codex_protocol::models::LocalShellAction;
+use codex_protocol::models::LocalShellExecAction;
+use codex_protocol::models::LocalShellStatus;
+use codex_protocol::models::ReasoningItemContent;
+use codex_protocol::models::ReasoningItemReasoningSummary;
+use pretty_assertions::assert_eq;
+use regex_lite::Regex;
+
+fn assistant_msg(text: &str) -> ResponseItem {
+    ResponseItem::Message {
+        id: None,
+        role: "assistant".to_string(),
+        content: vec![ContentItem::OutputText {
+            text: text.to_string(),
+        }],
+    }
+}
+
+fn create_history_with_items(items: Vec<ResponseItem>) -> ContextManager {
+    let mut h = ContextManager::new();
+    h.record_items(items.iter());
+    h
+}
+
+fn user_msg(text: &str) -> ResponseItem {
+    ResponseItem::Message {
+        id: None,
+        role: "user".to_string(),
+        content: vec![ContentItem::OutputText {
+            text: text.to_string(),
+        }],
+    }
+}
+
+fn reasoning_msg(text: &str) -> ResponseItem {
+    ResponseItem::Reasoning {
+        id: String::new(),
+        summary: vec![ReasoningItemReasoningSummary::SummaryText {
+            text: "summary".to_string(),
+        }],
+        content: Some(vec![ReasoningItemContent::ReasoningText {
+            text: text.to_string(),
+        }]),
+        encrypted_content: None,
+    }
+}
+
+#[test]
+fn filters_non_api_messages() {
+    let mut h = ContextManager::default();
+    // System message is not API messages; Other is ignored.
+    let system = ResponseItem::Message {
+        id: None,
+        role: "system".to_string(),
+        content: vec![ContentItem::OutputText {
+            text: "ignored".to_string(),
+        }],
+    };
+    let reasoning = reasoning_msg("thinking...");
+    h.record_items([&system, &reasoning, &ResponseItem::Other]);
+
+    // User and assistant should be retained.
+    let u = user_msg("hi");
+    let a = assistant_msg("hello");
+    h.record_items([&u, &a]);
+
+    let items = h.contents();
+    assert_eq!(
+        items,
+        vec![
+            ResponseItem::Reasoning {
+                id: String::new(),
+                summary: vec![ReasoningItemReasoningSummary::SummaryText {
+                    text: "summary".to_string(),
+                }],
+                content: Some(vec![ReasoningItemContent::ReasoningText {
+                    text: "thinking...".to_string(),
+                }]),
+                encrypted_content: None,
+            },
+            ResponseItem::Message {
+                id: None,
+                role: "user".to_string(),
+                content: vec![ContentItem::OutputText {
+                    text: "hi".to_string()
+                }]
+            },
+            ResponseItem::Message {
+                id: None,
+                role: "assistant".to_string(),
+                content: vec![ContentItem::OutputText {
+                    text: "hello".to_string()
+                }]
+            }
+        ]
+    );
+}
+
+#[test]
+fn get_history_for_prompt_drops_ghost_commits() {
+    let items = vec![ResponseItem::GhostSnapshot {
+        ghost_commit: GhostCommit::new("ghost-1".to_string(), None, Vec::new(), Vec::new()),
+    }];
+    let mut history = create_history_with_items(items);
+    let filtered = history.get_history_for_prompt();
+    assert_eq!(filtered, vec![]);
+}
+
+#[test]
+fn remove_first_item_removes_matching_output_for_function_call() {
+    let items = vec![
+        ResponseItem::FunctionCall {
+            id: None,
+            name: "do_it".to_string(),
+            arguments: "{}".to_string(),
+            call_id: "call-1".to_string(),
+        },
+        ResponseItem::FunctionCallOutput {
+            call_id: "call-1".to_string(),
+            output: FunctionCallOutputPayload {
+                content: "ok".to_string(),
+                ..Default::default()
+            },
+        },
+    ];
+    let mut h = create_history_with_items(items);
+    h.remove_first_item();
+    assert_eq!(h.contents(), vec![]);
+}
+
+#[test]
+fn remove_first_item_removes_matching_call_for_output() {
+    let items = vec![
+        ResponseItem::FunctionCallOutput {
+            call_id: "call-2".to_string(),
+            output: FunctionCallOutputPayload {
+                content: "ok".to_string(),
+                ..Default::default()
+            },
+        },
+        ResponseItem::FunctionCall {
+            id: None,
+            name: "do_it".to_string(),
+            arguments: "{}".to_string(),
+            call_id: "call-2".to_string(),
+        },
+    ];
+    let mut h = create_history_with_items(items);
+    h.remove_first_item();
+    assert_eq!(h.contents(), vec![]);
+}
+
+#[test]
+fn remove_first_item_handles_local_shell_pair() {
+    let items = vec![
+        ResponseItem::LocalShellCall {
+            id: None,
+            call_id: Some("call-3".to_string()),
+            status: LocalShellStatus::Completed,
+            action: LocalShellAction::Exec(LocalShellExecAction {
+                command: vec!["echo".to_string(), "hi".to_string()],
+                timeout_ms: None,
+                working_directory: None,
+                env: None,
+                user: None,
+            }),
+        },
+        ResponseItem::FunctionCallOutput {
+            call_id: "call-3".to_string(),
+            output: FunctionCallOutputPayload {
+                content: "ok".to_string(),
+                ..Default::default()
+            },
+        },
+    ];
+    let mut h = create_history_with_items(items);
+    h.remove_first_item();
+    assert_eq!(h.contents(), vec![]);
+}
+
+#[test]
+fn remove_first_item_handles_custom_tool_pair() {
+    let items = vec![
+        ResponseItem::CustomToolCall {
+            id: None,
+            status: None,
+            call_id: "tool-1".to_string(),
+            name: "my_tool".to_string(),
+            input: "{}".to_string(),
+        },
+        ResponseItem::CustomToolCallOutput {
+            call_id: "tool-1".to_string(),
+            output: "ok".to_string(),
+        },
+    ];
+    let mut h = create_history_with_items(items);
+    h.remove_first_item();
+    assert_eq!(h.contents(), vec![]);
+}
+
+#[test]
+fn normalization_retains_local_shell_outputs() {
+    let items = vec![
+        ResponseItem::LocalShellCall {
+            id: None,
+            call_id: Some("shell-1".to_string()),
+            status: LocalShellStatus::Completed,
+            action: LocalShellAction::Exec(LocalShellExecAction {
+                command: vec!["echo".to_string(), "hi".to_string()],
+                timeout_ms: None,
+                working_directory: None,
+                env: None,
+                user: None,
+            }),
+        },
+        ResponseItem::FunctionCallOutput {
+            call_id: "shell-1".to_string(),
+            output: FunctionCallOutputPayload {
+                content: "ok".to_string(),
+                ..Default::default()
+            },
+        },
+    ];
+
+    let mut history = create_history_with_items(items.clone());
+    let normalized = history.get_history();
+    assert_eq!(normalized, items);
+}
+
+#[test]
+fn record_items_truncates_function_call_output_content() {
+    let mut history = ContextManager::new();
+    let long_line = "a very long line to trigger truncation\n";
+    let long_output = long_line.repeat(2_500);
+    let item = ResponseItem::FunctionCallOutput {
+        call_id: "call-100".to_string(),
+        output: FunctionCallOutputPayload {
+            content: long_output.clone(),
+            success: Some(true),
+            ..Default::default()
+        },
+    };
+
+    history.record_items([&item]);
+
+    assert_eq!(history.items.len(), 1);
+    match &history.items[0] {
+        ResponseItem::FunctionCallOutput { output, .. } => {
+            assert_ne!(output.content, long_output);
+            assert!(
+                output.content.starts_with("Total output lines:"),
+                "expected truncated summary, got {}",
+                output.content
+            );
+        }
+        other => panic!("unexpected history item: {other:?}"),
+    }
+}
+
+#[test]
+fn record_items_truncates_custom_tool_call_output_content() {
+    let mut history = ContextManager::new();
+    let line = "custom output that is very long\n";
+    let long_output = line.repeat(2_500);
+    let item = ResponseItem::CustomToolCallOutput {
+        call_id: "tool-200".to_string(),
+        output: long_output.clone(),
+    };
+
+    history.record_items([&item]);
+
+    assert_eq!(history.items.len(), 1);
+    match &history.items[0] {
+        ResponseItem::CustomToolCallOutput { output, .. } => {
+            assert_ne!(output, &long_output);
+            assert!(
+                output.starts_with("Total output lines:"),
+                "expected truncated summary, got {output}"
+            );
+        }
+        other => panic!("unexpected history item: {other:?}"),
+    }
+}
+
+fn assert_truncated_message_matches(message: &str, line: &str, total_lines: usize) {
+    let pattern = truncated_message_pattern(line, total_lines);
+    let regex = Regex::new(&pattern).unwrap_or_else(|err| {
+        panic!("failed to compile regex {pattern}: {err}");
+    });
+    let captures = regex
+        .captures(message)
+        .unwrap_or_else(|| panic!("message failed to match pattern {pattern}: {message}"));
+    let body = captures
+        .name("body")
+        .expect("missing body capture")
+        .as_str();
+    assert!(
+        body.len() <= truncate::MODEL_FORMAT_MAX_BYTES,
+        "body exceeds byte limit: {} bytes",
+        body.len()
+    );
+}
+
+fn truncated_message_pattern(line: &str, total_lines: usize) -> String {
+    let head_take = truncate::MODEL_FORMAT_HEAD_LINES.min(total_lines);
+    let tail_take = truncate::MODEL_FORMAT_TAIL_LINES.min(total_lines.saturating_sub(head_take));
+    let omitted = total_lines.saturating_sub(head_take + tail_take);
+    let escaped_line = regex_lite::escape(line);
+    if omitted == 0 {
+        return format!(
+            r"(?s)^Total output lines: {total_lines}\n\n(?P<body>{escaped_line}.*\n\[\.{{3}} output truncated to fit {max_bytes} bytes \.{{3}}]\n\n.*)$",
+            max_bytes = truncate::MODEL_FORMAT_MAX_BYTES,
+        );
+    }
+    format!(
+        r"(?s)^Total output lines: {total_lines}\n\n(?P<body>{escaped_line}.*\n\[\.{{3}} omitted {omitted} of {total_lines} lines \.{{3}}]\n\n.*)$",
+    )
+}
+
+#[test]
+fn format_exec_output_truncates_large_error() {
+    let line = "very long execution error line that should trigger truncation\n";
+    let large_error = line.repeat(2_500); // way beyond both byte and line limits
+
+    let truncated = truncate::format_output_for_model_body(&large_error);
+
+    let total_lines = large_error.lines().count();
+    assert_truncated_message_matches(&truncated, line, total_lines);
+    assert_ne!(truncated, large_error);
+}
+
+#[test]
+fn format_exec_output_marks_byte_truncation_without_omitted_lines() {
+    let long_line = "a".repeat(truncate::MODEL_FORMAT_MAX_BYTES + 50);
+    let truncated = truncate::format_output_for_model_body(&long_line);
+
+    assert_ne!(truncated, long_line);
+    let marker_line = format!(
+        "[... output truncated to fit {} bytes ...]",
+        truncate::MODEL_FORMAT_MAX_BYTES
+    );
+    assert!(
+        truncated.contains(&marker_line),
+        "missing byte truncation marker: {truncated}"
+    );
+    assert!(
+        !truncated.contains("omitted"),
+        "line omission marker should not appear when no lines were dropped: {truncated}"
+    );
+}
+
+#[test]
+fn format_exec_output_returns_original_when_within_limits() {
+    let content = "example output\n".repeat(10);
+
+    assert_eq!(truncate::format_output_for_model_body(&content), content);
+}
+
+#[test]
+fn format_exec_output_reports_omitted_lines_and_keeps_head_and_tail() {
+    let total_lines = truncate::MODEL_FORMAT_MAX_LINES + 100;
+    let content: String = (0..total_lines)
+        .map(|idx| format!("line-{idx}\n"))
+        .collect();
+
+    let truncated = truncate::format_output_for_model_body(&content);
+    let omitted = total_lines - truncate::MODEL_FORMAT_MAX_LINES;
+    let expected_marker = format!("[... omitted {omitted} of {total_lines} lines ...]");
+
+    assert!(
+        truncated.contains(&expected_marker),
+        "missing omitted marker: {truncated}"
+    );
+    assert!(
+        truncated.contains("line-0\n"),
+        "expected head line to remain: {truncated}"
+    );
+
+    let last_line = format!("line-{}\n", total_lines - 1);
+    assert!(
+        truncated.contains(&last_line),
+        "expected tail line to remain: {truncated}"
+    );
+}
+
+#[test]
+fn format_exec_output_prefers_line_marker_when_both_limits_exceeded() {
+    let total_lines = truncate::MODEL_FORMAT_MAX_LINES + 42;
+    let long_line = "x".repeat(256);
+    let content: String = (0..total_lines)
+        .map(|idx| format!("line-{idx}-{long_line}\n"))
+        .collect();
+
+    let truncated = truncate::format_output_for_model_body(&content);
+
+    assert!(
+        truncated.contains("[... omitted 42 of 298 lines ...]"),
+        "expected omitted marker when line count exceeds limit: {truncated}"
+    );
+    assert!(
+        !truncated.contains("output truncated to fit"),
+        "line omission marker should take precedence over byte marker: {truncated}"
+    );
+}
+
+#[test]
+fn truncates_across_multiple_under_limit_texts_and_reports_omitted() {
+    // Arrange: several text items, none exceeding per-item limit, but total exceeds budget.
+    let budget = truncate::MODEL_FORMAT_MAX_BYTES;
+    let t1_len = (budget / 2).saturating_sub(10);
+    let t2_len = (budget / 2).saturating_sub(10);
+    let remaining_after_t1_t2 = budget.saturating_sub(t1_len + t2_len);
+    let t3_len = 50; // gets truncated to remaining_after_t1_t2
+    let t4_len = 5; // omitted
+    let t5_len = 7; // omitted
+
+    let t1 = "a".repeat(t1_len);
+    let t2 = "b".repeat(t2_len);
+    let t3 = "c".repeat(t3_len);
+    let t4 = "d".repeat(t4_len);
+    let t5 = "e".repeat(t5_len);
+
+    let item = ResponseItem::FunctionCallOutput {
+        call_id: "call-omit".to_string(),
+        output: FunctionCallOutputPayload {
+            content: "irrelevant".to_string(),
+            content_items: Some(vec![
+                FunctionCallOutputContentItem::InputText { text: t1 },
+                FunctionCallOutputContentItem::InputText { text: t2 },
+                FunctionCallOutputContentItem::InputImage {
+                    image_url: "img:mid".to_string(),
+                },
+                FunctionCallOutputContentItem::InputText { text: t3 },
+                FunctionCallOutputContentItem::InputText { text: t4 },
+                FunctionCallOutputContentItem::InputText { text: t5 },
+            ]),
+            success: Some(true),
+        },
+    };
+
+    let mut history = ContextManager::new();
+    history.record_items([&item]);
+    assert_eq!(history.items.len(), 1);
+    let json = serde_json::to_value(&history.items[0]).expect("serialize to json");
+
+    let output = json
+        .get("output")
+        .expect("output field")
+        .as_array()
+        .expect("array output");
+
+    // Expect: t1 (full), t2 (full), image, t3 (truncated), summary mentioning 2 omitted.
+    assert_eq!(output.len(), 5);
+
+    let first = output[0].as_object().expect("first obj");
+    assert_eq!(first.get("type").unwrap(), "input_text");
+    let first_text = first.get("text").unwrap().as_str().unwrap();
+    assert_eq!(first_text.len(), t1_len);
+
+    let second = output[1].as_object().expect("second obj");
+    assert_eq!(second.get("type").unwrap(), "input_text");
+    let second_text = second.get("text").unwrap().as_str().unwrap();
+    assert_eq!(second_text.len(), t2_len);
+
+    assert_eq!(
+        output[2],
+        serde_json::json!({"type": "input_image", "image_url": "img:mid"})
+    );
+
+    let fourth = output[3].as_object().expect("fourth obj");
+    assert_eq!(fourth.get("type").unwrap(), "input_text");
+    let fourth_text = fourth.get("text").unwrap().as_str().unwrap();
+    assert_eq!(fourth_text.len(), remaining_after_t1_t2);
+
+    let summary = output[4].as_object().expect("summary obj");
+    assert_eq!(summary.get("type").unwrap(), "input_text");
+    let summary_text = summary.get("text").unwrap().as_str().unwrap();
+    assert!(summary_text.contains("omitted 2 text items"));
+}
+
+//TODO(aibrahim): run CI in release mode.
+#[cfg(not(debug_assertions))]
+#[test]
+fn normalize_adds_missing_output_for_function_call() {
+    let items = vec![ResponseItem::FunctionCall {
+        id: None,
+        name: "do_it".to_string(),
+        arguments: "{}".to_string(),
+        call_id: "call-x".to_string(),
+    }];
+    let mut h = create_history_with_items(items);
+
+    h.normalize_history();
+
+    assert_eq!(
+        h.contents(),
+        vec![
+            ResponseItem::FunctionCall {
+                id: None,
+                name: "do_it".to_string(),
+                arguments: "{}".to_string(),
+                call_id: "call-x".to_string(),
+            },
+            ResponseItem::FunctionCallOutput {
+                call_id: "call-x".to_string(),
+                output: FunctionCallOutputPayload {
+                    content: "aborted".to_string(),
+                    ..Default::default()
+                },
+            },
+        ]
+    );
+}
+
+#[cfg(not(debug_assertions))]
+#[test]
+fn normalize_adds_missing_output_for_custom_tool_call() {
+    let items = vec![ResponseItem::CustomToolCall {
+        id: None,
+        status: None,
+        call_id: "tool-x".to_string(),
+        name: "custom".to_string(),
+        input: "{}".to_string(),
+    }];
+    let mut h = create_history_with_items(items);
+
+    h.normalize_history();
+
+    assert_eq!(
+        h.contents(),
+        vec![
+            ResponseItem::CustomToolCall {
+                id: None,
+                status: None,
+                call_id: "tool-x".to_string(),
+                name: "custom".to_string(),
+                input: "{}".to_string(),
+            },
+            ResponseItem::CustomToolCallOutput {
+                call_id: "tool-x".to_string(),
+                output: "aborted".to_string(),
+            },
+        ]
+    );
+}
+
+#[cfg(not(debug_assertions))]
+#[test]
+fn normalize_adds_missing_output_for_local_shell_call_with_id() {
+    let items = vec![ResponseItem::LocalShellCall {
+        id: None,
+        call_id: Some("shell-1".to_string()),
+        status: LocalShellStatus::Completed,
+        action: LocalShellAction::Exec(LocalShellExecAction {
+            command: vec!["echo".to_string(), "hi".to_string()],
+            timeout_ms: None,
+            working_directory: None,
+            env: None,
+            user: None,
+        }),
+    }];
+    let mut h = create_history_with_items(items);
+
+    h.normalize_history();
+
+    assert_eq!(
+        h.contents(),
+        vec![
+            ResponseItem::LocalShellCall {
+                id: None,
+                call_id: Some("shell-1".to_string()),
+                status: LocalShellStatus::Completed,
+                action: LocalShellAction::Exec(LocalShellExecAction {
+                    command: vec!["echo".to_string(), "hi".to_string()],
+                    timeout_ms: None,
+                    working_directory: None,
+                    env: None,
+                    user: None,
+                }),
+            },
+            ResponseItem::FunctionCallOutput {
+                call_id: "shell-1".to_string(),
+                output: FunctionCallOutputPayload {
+                    content: "aborted".to_string(),
+                    ..Default::default()
+                },
+            },
+        ]
+    );
+}
+
+#[cfg(not(debug_assertions))]
+#[test]
+fn normalize_removes_orphan_function_call_output() {
+    let items = vec![ResponseItem::FunctionCallOutput {
+        call_id: "orphan-1".to_string(),
+        output: FunctionCallOutputPayload {
+            content: "ok".to_string(),
+            ..Default::default()
+        },
+    }];
+    let mut h = create_history_with_items(items);
+
+    h.normalize_history();
+
+    assert_eq!(h.contents(), vec![]);
+}
+
+#[cfg(not(debug_assertions))]
+#[test]
+fn normalize_removes_orphan_custom_tool_call_output() {
+    let items = vec![ResponseItem::CustomToolCallOutput {
+        call_id: "orphan-2".to_string(),
+        output: "ok".to_string(),
+    }];
+    let mut h = create_history_with_items(items);
+
+    h.normalize_history();
+
+    assert_eq!(h.contents(), vec![]);
+}
+
+#[cfg(not(debug_assertions))]
+#[test]
+fn normalize_mixed_inserts_and_removals() {
+    let items = vec![
+        // Will get an inserted output
+        ResponseItem::FunctionCall {
+            id: None,
+            name: "f1".to_string(),
+            arguments: "{}".to_string(),
+            call_id: "c1".to_string(),
+        },
+        // Orphan output that should be removed
+        ResponseItem::FunctionCallOutput {
+            call_id: "c2".to_string(),
+            output: FunctionCallOutputPayload {
+                content: "ok".to_string(),
+                ..Default::default()
+            },
+        },
+        // Will get an inserted custom tool output
+        ResponseItem::CustomToolCall {
+            id: None,
+            status: None,
+            call_id: "t1".to_string(),
+            name: "tool".to_string(),
+            input: "{}".to_string(),
+        },
+        // Local shell call also gets an inserted function call output
+        ResponseItem::LocalShellCall {
+            id: None,
+            call_id: Some("s1".to_string()),
+            status: LocalShellStatus::Completed,
+            action: LocalShellAction::Exec(LocalShellExecAction {
+                command: vec!["echo".to_string()],
+                timeout_ms: None,
+                working_directory: None,
+                env: None,
+                user: None,
+            }),
+        },
+    ];
+    let mut h = create_history_with_items(items);
+
+    h.normalize_history();
+
+    assert_eq!(
+        h.contents(),
+        vec![
+            ResponseItem::FunctionCall {
+                id: None,
+                name: "f1".to_string(),
+                arguments: "{}".to_string(),
+                call_id: "c1".to_string(),
+            },
+            ResponseItem::FunctionCallOutput {
+                call_id: "c1".to_string(),
+                output: FunctionCallOutputPayload {
+                    content: "aborted".to_string(),
+                    ..Default::default()
+                },
+            },
+            ResponseItem::CustomToolCall {
+                id: None,
+                status: None,
+                call_id: "t1".to_string(),
+                name: "tool".to_string(),
+                input: "{}".to_string(),
+            },
+            ResponseItem::CustomToolCallOutput {
+                call_id: "t1".to_string(),
+                output: "aborted".to_string(),
+            },
+            ResponseItem::LocalShellCall {
+                id: None,
+                call_id: Some("s1".to_string()),
+                status: LocalShellStatus::Completed,
+                action: LocalShellAction::Exec(LocalShellExecAction {
+                    command: vec!["echo".to_string()],
+                    timeout_ms: None,
+                    working_directory: None,
+                    env: None,
+                    user: None,
+                }),
+            },
+            ResponseItem::FunctionCallOutput {
+                call_id: "s1".to_string(),
+                output: FunctionCallOutputPayload {
+                    content: "aborted".to_string(),
+                    ..Default::default()
+                },
+            },
+        ]
+    );
+}
+
+// In debug builds we panic on normalization errors instead of silently fixing them.
+#[cfg(debug_assertions)]
+#[test]
+#[should_panic]
+fn normalize_adds_missing_output_for_function_call_panics_in_debug() {
+    let items = vec![ResponseItem::FunctionCall {
+        id: None,
+        name: "do_it".to_string(),
+        arguments: "{}".to_string(),
+        call_id: "call-x".to_string(),
+    }];
+    let mut h = create_history_with_items(items);
+    h.normalize_history();
+}
+
+#[cfg(debug_assertions)]
+#[test]
+#[should_panic]
+fn normalize_adds_missing_output_for_custom_tool_call_panics_in_debug() {
+    let items = vec![ResponseItem::CustomToolCall {
+        id: None,
+        status: None,
+        call_id: "tool-x".to_string(),
+        name: "custom".to_string(),
+        input: "{}".to_string(),
+    }];
+    let mut h = create_history_with_items(items);
+    h.normalize_history();
+}
+
+#[cfg(debug_assertions)]
+#[test]
+#[should_panic]
+fn normalize_adds_missing_output_for_local_shell_call_with_id_panics_in_debug() {
+    let items = vec![ResponseItem::LocalShellCall {
+        id: None,
+        call_id: Some("shell-1".to_string()),
+        status: LocalShellStatus::Completed,
+        action: LocalShellAction::Exec(LocalShellExecAction {
+            command: vec!["echo".to_string(), "hi".to_string()],
+            timeout_ms: None,
+            working_directory: None,
+            env: None,
+            user: None,
+        }),
+    }];
+    let mut h = create_history_with_items(items);
+    h.normalize_history();
+}
+
+#[cfg(debug_assertions)]
+#[test]
+#[should_panic]
+fn normalize_removes_orphan_function_call_output_panics_in_debug() {
+    let items = vec![ResponseItem::FunctionCallOutput {
+        call_id: "orphan-1".to_string(),
+        output: FunctionCallOutputPayload {
+            content: "ok".to_string(),
+            ..Default::default()
+        },
+    }];
+    let mut h = create_history_with_items(items);
+    h.normalize_history();
+}
+
+#[cfg(debug_assertions)]
+#[test]
+#[should_panic]
+fn normalize_removes_orphan_custom_tool_call_output_panics_in_debug() {
+    let items = vec![ResponseItem::CustomToolCallOutput {
+        call_id: "orphan-2".to_string(),
+        output: "ok".to_string(),
+    }];
+    let mut h = create_history_with_items(items);
+    h.normalize_history();
+}
+
+#[cfg(debug_assertions)]
+#[test]
+#[should_panic]
+fn normalize_mixed_inserts_and_removals_panics_in_debug() {
+    let items = vec![
+        ResponseItem::FunctionCall {
+            id: None,
+            name: "f1".to_string(),
+            arguments: "{}".to_string(),
+            call_id: "c1".to_string(),
+        },
+        ResponseItem::FunctionCallOutput {
+            call_id: "c2".to_string(),
+            output: FunctionCallOutputPayload {
+                content: "ok".to_string(),
+                ..Default::default()
+            },
+        },
+        ResponseItem::CustomToolCall {
+            id: None,
+            status: None,
+            call_id: "t1".to_string(),
+            name: "tool".to_string(),
+            input: "{}".to_string(),
+        },
+        ResponseItem::LocalShellCall {
+            id: None,
+            call_id: Some("s1".to_string()),
+            status: LocalShellStatus::Completed,
+            action: LocalShellAction::Exec(LocalShellExecAction {
+                command: vec!["echo".to_string()],
+                timeout_ms: None,
+                working_directory: None,
+                env: None,
+                user: None,
+            }),
+        },
+    ];
+    let mut h = create_history_with_items(items);
+    h.normalize_history();
+}

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

@@ -0,0 +1,6 @@
+mod history;
+mod normalize;
+mod truncate;
+
+pub(crate) use history::ContextManager;
+pub(crate) use truncate::format_output_for_model_body;

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

@@ -0,0 +1,213 @@
+use std::collections::HashSet;
+
+use codex_protocol::models::FunctionCallOutputPayload;
+use codex_protocol::models::ResponseItem;
+
+use crate::util::error_or_panic;
+
+pub(crate) fn ensure_call_outputs_present(items: &mut Vec<ResponseItem>) {
+    // Collect synthetic outputs to insert immediately after their calls.
+    // Store the insertion position (index of call) alongside the item so
+    // we can insert in reverse order and avoid index shifting.
+    let mut missing_outputs_to_insert: Vec<(usize, ResponseItem)> = Vec::new();
+
+    for (idx, item) in items.iter().enumerate() {
+        match item {
+            ResponseItem::FunctionCall { call_id, .. } => {
+                let has_output = items.iter().any(|i| match i {
+                    ResponseItem::FunctionCallOutput {
+                        call_id: existing, ..
+                    } => existing == call_id,
+                    _ => false,
+                });
+
+                if !has_output {
+                    error_or_panic(format!(
+                        "Function call output is missing for call id: {call_id}"
+                    ));
+                    missing_outputs_to_insert.push((
+                        idx,
+                        ResponseItem::FunctionCallOutput {
+                            call_id: call_id.clone(),
+                            output: FunctionCallOutputPayload {
+                                content: "aborted".to_string(),
+                                ..Default::default()
+                            },
+                        },
+                    ));
+                }
+            }
+            ResponseItem::CustomToolCall { call_id, .. } => {
+                let has_output = items.iter().any(|i| match i {
+                    ResponseItem::CustomToolCallOutput {
+                        call_id: existing, ..
+                    } => existing == call_id,
+                    _ => false,
+                });
+
+                if !has_output {
+                    error_or_panic(format!(
+                        "Custom tool call output is missing for call id: {call_id}"
+                    ));
+                    missing_outputs_to_insert.push((
+                        idx,
+                        ResponseItem::CustomToolCallOutput {
+                            call_id: call_id.clone(),
+                            output: "aborted".to_string(),
+                        },
+                    ));
+                }
+            }
+            // LocalShellCall is represented in upstream streams by a FunctionCallOutput
+            ResponseItem::LocalShellCall { call_id, .. } => {
+                if let Some(call_id) = call_id.as_ref() {
+                    let has_output = items.iter().any(|i| match i {
+                        ResponseItem::FunctionCallOutput {
+                            call_id: existing, ..
+                        } => existing == call_id,
+                        _ => false,
+                    });
+
+                    if !has_output {
+                        error_or_panic(format!(
+                            "Local shell call output is missing for call id: {call_id}"
+                        ));
+                        missing_outputs_to_insert.push((
+                            idx,
+                            ResponseItem::FunctionCallOutput {
+                                call_id: call_id.clone(),
+                                output: FunctionCallOutputPayload {
+                                    content: "aborted".to_string(),
+                                    ..Default::default()
+                                },
+                            },
+                        ));
+                    }
+                }
+            }
+            _ => {}
+        }
+    }
+
+    // Insert synthetic outputs in reverse index order to avoid re-indexing.
+    for (idx, output_item) in missing_outputs_to_insert.into_iter().rev() {
+        items.insert(idx + 1, output_item);
+    }
+}
+
+pub(crate) fn remove_orphan_outputs(items: &mut Vec<ResponseItem>) {
+    let function_call_ids: HashSet<String> = items
+        .iter()
+        .filter_map(|i| match i {
+            ResponseItem::FunctionCall { call_id, .. } => Some(call_id.clone()),
+            _ => None,
+        })
+        .collect();
+
+    let local_shell_call_ids: HashSet<String> = items
+        .iter()
+        .filter_map(|i| match i {
+            ResponseItem::LocalShellCall {
+                call_id: Some(call_id),
+                ..
+            } => Some(call_id.clone()),
+            _ => None,
+        })
+        .collect();
+
+    let custom_tool_call_ids: HashSet<String> = items
+        .iter()
+        .filter_map(|i| match i {
+            ResponseItem::CustomToolCall { call_id, .. } => Some(call_id.clone()),
+            _ => None,
+        })
+        .collect();
+
+    items.retain(|item| match item {
+        ResponseItem::FunctionCallOutput { call_id, .. } => {
+            let has_match =
+                function_call_ids.contains(call_id) || local_shell_call_ids.contains(call_id);
+            if !has_match {
+                error_or_panic(format!(
+                    "Orphan function call output for call id: {call_id}"
+                ));
+            }
+            has_match
+        }
+        ResponseItem::CustomToolCallOutput { call_id, .. } => {
+            let has_match = custom_tool_call_ids.contains(call_id);
+            if !has_match {
+                error_or_panic(format!(
+                    "Orphan custom tool call output for call id: {call_id}"
+                ));
+            }
+            has_match
+        }
+        _ => true,
+    });
+}
+
+pub(crate) fn remove_corresponding_for(items: &mut Vec<ResponseItem>, item: &ResponseItem) {
+    match item {
+        ResponseItem::FunctionCall { call_id, .. } => {
+            remove_first_matching(items, |i| {
+                matches!(
+                    i,
+                    ResponseItem::FunctionCallOutput {
+                        call_id: existing, ..
+                    } if existing == call_id
+                )
+            });
+        }
+        ResponseItem::FunctionCallOutput { call_id, .. } => {
+            if let Some(pos) = items.iter().position(|i| {
+                matches!(i, ResponseItem::FunctionCall { call_id: existing, .. } if existing == call_id)
+            }) {
+                items.remove(pos);
+            } else if let Some(pos) = items.iter().position(|i| {
+                matches!(i, ResponseItem::LocalShellCall { call_id: Some(existing), .. } if existing == call_id)
+            }) {
+                items.remove(pos);
+            }
+        }
+        ResponseItem::CustomToolCall { call_id, .. } => {
+            remove_first_matching(items, |i| {
+                matches!(
+                    i,
+                    ResponseItem::CustomToolCallOutput {
+                        call_id: existing, ..
+                    } if existing == call_id
+                )
+            });
+        }
+        ResponseItem::CustomToolCallOutput { call_id, .. } => {
+            remove_first_matching(
+                items,
+                |i| matches!(i, ResponseItem::CustomToolCall { call_id: existing, .. } if existing == call_id),
+            );
+        }
+        ResponseItem::LocalShellCall {
+            call_id: Some(call_id),
+            ..
+        } => {
+            remove_first_matching(items, |i| {
+                matches!(
+                    i,
+                    ResponseItem::FunctionCallOutput {
+                        call_id: existing, ..
+                    } if existing == call_id
+                )
+            });
+        }
+        _ => {}
+    }
+}
+
+fn remove_first_matching<F>(items: &mut Vec<ResponseItem>, predicate: F)
+where
+    F: Fn(&ResponseItem) -> bool,
+{
+    if let Some(pos) = items.iter().position(predicate) {
+        items.remove(pos);
+    }
+}

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

@@ -0,0 +1,128 @@
+use codex_protocol::models::FunctionCallOutputContentItem;
+use codex_utils_string::take_bytes_at_char_boundary;
+use codex_utils_string::take_last_bytes_at_char_boundary;
+
+// Model-formatting limits: clients get full streams; only content sent to the model is truncated.
+pub(crate) const MODEL_FORMAT_MAX_BYTES: usize = 10 * 1024; // 10 KiB
+pub(crate) const MODEL_FORMAT_MAX_LINES: usize = 256; // lines
+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;
+
+pub(crate) fn globally_truncate_function_output_items(
+    items: &[FunctionCallOutputContentItem],
+) -> Vec<FunctionCallOutputContentItem> {
+    let mut out: Vec<FunctionCallOutputContentItem> = Vec::with_capacity(items.len());
+    let mut remaining = MODEL_FORMAT_MAX_BYTES;
+    let mut omitted_text_items = 0usize;
+
+    for it in items {
+        match it {
+            FunctionCallOutputContentItem::InputText { text } => {
+                if remaining == 0 {
+                    omitted_text_items += 1;
+                    continue;
+                }
+
+                let len = text.len();
+                if len <= remaining {
+                    out.push(FunctionCallOutputContentItem::InputText { text: text.clone() });
+                    remaining -= len;
+                } else {
+                    let slice = take_bytes_at_char_boundary(text, remaining);
+                    if !slice.is_empty() {
+                        out.push(FunctionCallOutputContentItem::InputText {
+                            text: slice.to_string(),
+                        });
+                    }
+                    remaining = 0;
+                }
+            }
+            // todo(aibrahim): handle input images; resize
+            FunctionCallOutputContentItem::InputImage { image_url } => {
+                out.push(FunctionCallOutputContentItem::InputImage {
+                    image_url: image_url.clone(),
+                });
+            }
+        }
+    }
+
+    if omitted_text_items > 0 {
+        out.push(FunctionCallOutputContentItem::InputText {
+            text: format!("[omitted {omitted_text_items} text items ...]"),
+        });
+    }
+
+    out
+}
+
+pub(crate) fn format_output_for_model_body(content: &str) -> String {
+    // Head+tail truncation for the model: show the beginning and end with an elision.
+    // Clients still receive full streams; only this formatted summary is capped.
+    let total_lines = content.lines().count();
+    if content.len() <= MODEL_FORMAT_MAX_BYTES && total_lines <= MODEL_FORMAT_MAX_LINES {
+        return content.to_string();
+    }
+    let output = truncate_formatted_exec_output(content, total_lines);
+    format!("Total output lines: {total_lines}\n\n{output}")
+}
+
+fn truncate_formatted_exec_output(content: &str, total_lines: usize) -> String {
+    let segments: Vec<&str> = content.split_inclusive('\n').collect();
+    let head_take = MODEL_FORMAT_HEAD_LINES.min(segments.len());
+    let tail_take = MODEL_FORMAT_TAIL_LINES.min(segments.len().saturating_sub(head_take));
+    let omitted = segments.len().saturating_sub(head_take + tail_take);
+
+    let head_slice_end: usize = segments
+        .iter()
+        .take(head_take)
+        .map(|segment| segment.len())
+        .sum();
+    let tail_slice_start: usize = if tail_take == 0 {
+        content.len()
+    } else {
+        content.len()
+            - segments
+                .iter()
+                .rev()
+                .take(tail_take)
+                .map(|segment| segment.len())
+                .sum::<usize>()
+    };
+    let head_slice = &content[..head_slice_end];
+    let tail_slice = &content[tail_slice_start..];
+    let truncated_by_bytes = content.len() > MODEL_FORMAT_MAX_BYTES;
+    // this is a bit wrong. We are counting metadata lines and not just shell output lines.
+    let marker = if omitted > 0 {
+        Some(format!(
+            "\n[... omitted {omitted} of {total_lines} lines ...]\n\n"
+        ))
+    } else if truncated_by_bytes {
+        Some(format!(
+            "\n[... output truncated to fit {MODEL_FORMAT_MAX_BYTES} bytes ...]\n\n"
+        ))
+    } else {
+        None
+    };
+
+    let marker_len = marker.as_ref().map_or(0, String::len);
+    let base_head_budget = MODEL_FORMAT_HEAD_BYTES.min(MODEL_FORMAT_MAX_BYTES);
+    let head_budget = base_head_budget.min(MODEL_FORMAT_MAX_BYTES.saturating_sub(marker_len));
+    let head_part = take_bytes_at_char_boundary(head_slice, head_budget);
+    let mut result = String::with_capacity(MODEL_FORMAT_MAX_BYTES.min(content.len()));
+
+    result.push_str(head_part);
+    if let Some(marker_text) = marker.as_ref() {
+        result.push_str(marker_text);
+    }
+
+    let remaining = MODEL_FORMAT_MAX_BYTES.saturating_sub(result.len());
+    if remaining == 0 {
+        return result;
+    }
+
+    let tail_part = take_last_bytes_at_char_boundary(tail_slice, remaining);
+    result.push_str(tail_part);
+
+    result
+}

codex-rs/core/src/lib.rs

@@ -18,7 +18,7 @@ mod codex_delegate;
 mod command_safety;
 pub mod config;
 pub mod config_loader;
-mod conversation_history;
+mod context_manager;
 pub mod custom_prompts;
 mod environment_context;
 pub mod error;

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,
         }
     }
@@ -34,7 +34,7 @@ impl SessionState {
         self.history.record_items(items)
     }
 
-    pub(crate) fn clone_history(&self) -> ConversationHistory {
+    pub(crate) fn clone_history(&self) -> ContextManager {
         self.history.clone()
     }
 

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

@@ -9,7 +9,7 @@ pub mod runtimes;
 pub mod sandboxing;
 pub mod spec;
 
-use crate::conversation_history::format_output_for_model_body;
+use crate::context_manager::format_output_for_model_body;
 use crate::exec::ExecToolCallOutput;
 pub use router::ToolRouter;
 use serde::Serialize;