feat(tui): display main agent TodoWrite items above input field by echobt · Pull Request #120 · CortexLM/cortex

echobt · 2026-02-05T11:14:10Z

Summary

This PR implements a TodoWrite display feature for the main Cortex agent in the TUI. When the main agent uses the TodoWrite tool, the todo list is displayed above the input field, providing real-time visibility into the agent's planned tasks.

Changes

State Management (`src/cortex-tui/src/app/state.rs`)

Added MainAgentTodoItem struct with content and status fields
Added MainAgentTodoStatus enum (Pending, InProgress, Completed)
Added main_agent_todos: Vec<MainAgentTodoItem> field to AppState
Added methods: update_main_todos(), clear_main_todos(), has_main_todos()

Tool Event Handling (`src/cortex-tui/src/runner/event_loop/tools.rs`)

Intercepts TodoWrite tool calls in spawn_tool_execution()
Parses todos immediately (before execution) for real-time display
Supports both numbered string format (1. [status] content) and array format

Rendering (`src/cortex-tui/src/views/minimal_session/rendering.rs`)

Added render_main_agent_todos() function
Displays with "📋 Plan" header
Status indicators: ○ pending, ● in_progress, ✓ completed
Completed items show with strikethrough styling (Modifier::CROSSED_OUT)
Status colors: pending=muted, in_progress=accent, completed=success

View Integration (`src/cortex-tui/src/views/minimal_session/view.rs`)

Integrated todo display in Widget render method
Positioned above status indicator and input field
Dynamic height calculation based on number of todos

Visual Example

📋 Plan
  ⎿ ○ First task
    ● Second task (highlighted)
    ✓ ~~Third task~~ (strikethrough)

Acceptance Criteria

TodoWrite items from the main agent are tracked in application state
A todo list is displayed above the input field when todos exist
Each todo item shows its status (pending, in_progress, completed)
Completed todo items are displayed with strikethrough styling
The display updates in real-time when TodoWrite tool is called
Empty state: no todo section shown when there are no todos

Testing

cargo check -p cortex-tui passes with no errors

greptile-apps · 2026-02-05T11:16:57Z

Greptile Overview

Greptile Summary

This PR adds a “Plan” section to the minimal session TUI that shows the main agent’s TodoWrite items above the input area. It introduces main-agent todo types stored on AppState, intercepts TodoWrite tool calls in the event loop to parse/update todos immediately (before tool execution) for real-time display, and adds a renderer that shows status markers and strikethrough for completed items.

Key integration points:

EventLoop::spawn_tool_execution updates AppState.main_agent_todos when the tool name is TodoWrite.
MinimalSessionView reserves vertical space near the bottom and renders the todo list just above the status indicator/input widget.

Issues to address before merge are mainly around stale todo state (TodoWrite calls that clear/omit items don’t currently clear UI state) and layout safety when the scrollable content height exceeds its allocation (todo section can render out of bounds/overlap).

Confidence Score: 3/5

This PR is mergeable after fixing a couple of correctness issues in todo state updates and layout bounds handling.
Core functionality is straightforward and localized, but there are definite edge cases that will produce incorrect UI (stale todos that never clear, and potential out-of-bounds/overlap rendering when content height exceeds allocation). Also, automated verification couldn’t be run in this environment (cargo missing).
src/cortex-tui/src/runner/event_loop/tools.rs; src/cortex-tui/src/views/minimal_session/view.rs

Important Files Changed

Filename	Overview
src/cortex-tui/src/app/mod.rs	Re-exports new main-agent todo types from state module.
src/cortex-tui/src/app/state.rs	Adds MainAgentTodoItem/Status types and stores main_agent_todos in AppState with basic update/clear helpers.
src/cortex-tui/src/runner/event_loop/tools.rs	Intercepts TodoWrite calls to parse/update main-agent todos before tool execution; current parsing/update logic can leave stale todos on empty/unsupported formats.
src/cortex-tui/src/views/minimal_session/rendering.rs	Adds render_main_agent_todos to display main-agent plan with status markers and strikethrough for completed items.
src/cortex-tui/src/views/minimal_session/view.rs	Integrates main-agent todo rendering above status/input and reserves extra height; current placement can render out of bounds if content height exceeds allocation.

Sequence Diagram

sequenceDiagram
    participant LLM as Main agent (LLM)
    participant EL as EventLoop
    participant AS as AppState
    participant TR as ToolRegistry
    participant UI as MinimalSessionView

    LLM->>EL: ToolCall: TodoWrite(args)
    EL->>AS: handle_main_agent_todo_write(args)
    Note over AS: Updates main_agent_todos for immediate display
    EL->>TR: execute("TodoWrite", args) (async)
    UI->>AS: has_main_todos()/main_agent_todos
    UI-->>UI: render_main_agent_todos()
    TR-->>EL: ToolEvent::Completed/Failed
    EL-->>AS: (no todo update on completion)
    UI->>AS: reads latest state on next render

greptile-apps

_{5 files reviewed, 3 comments}

_{Edit Code Review Agent Settings | Greptile}

greptile-apps · 2026-02-05T11:17:00Z

src/cortex-tui/src/runner/event_loop/tools.rs

+    /// Handle main agent's TodoWrite tool call.
+    /// Parses the todos argument and updates app_state for real-time display.
+    fn handle_main_agent_todo_write(&mut self, args: &serde_json::Value) {


Todo list never clears

handle_main_agent_todo_write() only updates app_state.main_agent_todos when the parsed todos vector is non-empty (e.g., if !todos.is_empty() { ... }). This means a valid TodoWrite call that intentionally sends an empty list (or an empty/whitespace string) will not clear the UI, leaving stale todos displayed. Consider explicitly clearing on empty input (e.g., call clear_main_todos() when todos parses but is empty) so the “empty state: no todo section shown” acceptance criterion is actually met.

Prompt To Fix With AI

This is a comment left during a code review. Path: src/cortex-tui/src/runner/event_loop/tools.rs Line: 651:653 Comment: **Todo list never clears** `handle_main_agent_todo_write()` only updates `app_state.main_agent_todos` when the parsed `todos` vector is non-empty (e.g., `if !todos.is_empty() { ... }`). This means a valid TodoWrite call that intentionally sends an empty list (or an empty/whitespace string) will *not* clear the UI, leaving stale todos displayed. Consider explicitly clearing on empty input (e.g., call `clear_main_todos()` when `todos` parses but is empty) so the “empty state: no todo section shown” acceptance criterion is actually met. How can I resolve this? If you propose a fix, please make it concise.

greptile-apps · 2026-02-05T11:17:01Z

src/cortex-tui/src/runner/event_loop/tools.rs

+        // Try to parse as string format first (numbered list)
+        if let Some(todos_str) = args.get("todos").and_then(|v| v.as_str()) {
+            let todos: Vec<MainAgentTodoItem> = todos_str
+                .lines()
+                .filter_map(|line| {
+                    // Parse lines like "1. [completed] First task"


Bracket parsing can drop todos

The string-format parser assumes each line contains [ and ] and uses line.find(']')/line.find('[') to slice status/content. If the main agent ever emits a numbered todo line without bracketed status (or with additional ] earlier in the content), that todo will be silently skipped, potentially resulting in an empty parsed list and (due to the non-empty guard) no state update. This causes the UI to show stale items even though a new TodoWrite was issued. A more robust parse should handle missing/unknown status and still capture the content.

Prompt To Fix With AI

This is a comment left during a code review. Path: src/cortex-tui/src/runner/event_loop/tools.rs Line: 657:662 Comment: **Bracket parsing can drop todos** The string-format parser assumes each line contains `[` and `]` and uses `line.find(']')`/`line.find('[')` to slice status/content. If the main agent ever emits a numbered todo line without bracketed status (or with additional `]` earlier in the content), that todo will be silently skipped, potentially resulting in an empty parsed list and (due to the non-empty guard) no state update. This causes the UI to show stale items even though a new TodoWrite was issued. A more robust parse should handle missing/unknown status and still capture the content. How can I resolve this? If you propose a fix, please make it concise.

greptile-apps · 2026-02-05T11:17:02Z

src/cortex-tui/src/views/minimal_session/view.rs

+        // 4.5. Main agent todos (if any) - above status indicator
+        if self.app_state.has_main_todos() {
+            let todo_lines =
+                render_main_agent_todos(&self.app_state.main_agent_todos, area.width, &self.colors);
+            let todo_area = Rect::new(area.x, next_y, area.width, main_todos_height);


Todo area can overlap

todo_area is rendered unconditionally at next_y with height main_todos_height, but next_y is derived from content_end_y + 1 where content_end_y comes from actual_content_height. If actual_content_height is larger than the allocated available_height (e.g., due to long welcome/messages rendering), next_y can already be past the bottom of area, and the todo section will render out-of-bounds/overlap subsequent regions. This is particularly easy to hit because adding main_todos_height reduces available_height but doesn’t constrain actual_content_height to that allocation.

Prompt To Fix With AI

This is a comment left during a code review. Path: src/cortex-tui/src/views/minimal_session/view.rs Line: 613:617 Comment: **Todo area can overlap** `todo_area` is rendered unconditionally at `next_y` with height `main_todos_height`, but `next_y` is derived from `content_end_y + 1` where `content_end_y` comes from `actual_content_height`. If `actual_content_height` is larger than the allocated `available_height` (e.g., due to long welcome/messages rendering), `next_y` can already be past the bottom of `area`, and the todo section will render out-of-bounds/overlap subsequent regions. This is particularly easy to hit because adding `main_todos_height` reduces `available_height` but doesn’t constrain `actual_content_height` to that allocation. How can I resolve this? If you propose a fix, please make it concise.

- Add MainAgentTodoItem and MainAgentTodoStatus types in state.rs - Add update_main_todos, clear_main_todos, has_main_todos methods - Parse TodoWrite tool calls in spawn_tool_execution for real-time display - Add render_main_agent_todos function with styled output - Integrate todos display in minimal session view layout - Re-export new types from app module

greptile-apps bot reviewed Feb 5, 2026

View reviewed changes

echobt force-pushed the feat/main-agent-todo-display branch from 441b95b to e95b74a Compare February 5, 2026 11:22

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feat(tui): display main agent TodoWrite items above input field#120

feat(tui): display main agent TodoWrite items above input field#120
echobt wants to merge 1 commit intomainfrom
feat/main-agent-todo-display

echobt commented Feb 5, 2026

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echobt commented Feb 5, 2026

Summary

Changes

State Management (src/cortex-tui/src/app/state.rs)

Tool Event Handling (src/cortex-tui/src/runner/event_loop/tools.rs)

Rendering (src/cortex-tui/src/views/minimal_session/rendering.rs)

View Integration (src/cortex-tui/src/views/minimal_session/view.rs)

Visual Example

Acceptance Criteria

Testing

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greptile-apps bot commented Feb 5, 2026

Greptile Overview

Greptile Summary

Confidence Score: 3/5

Important Files Changed

Sequence Diagram

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State Management (`src/cortex-tui/src/app/state.rs`)

Tool Event Handling (`src/cortex-tui/src/runner/event_loop/tools.rs`)

Rendering (`src/cortex-tui/src/views/minimal_session/rendering.rs`)

View Integration (`src/cortex-tui/src/views/minimal_session/view.rs`)