---
name: "Activity indicator still only shows Thinking despite bug 140 fix"
---

# Bug 147: Activity indicator still only shows Thinking despite bug 140 fix

## Description

Bug 140 fixed the frontend display condition but activity labels still never appear. The full data path has been traced and the suspected failure point identified.

## End-to-End Data Path

### 1. Frontend display (FIXED by bug 140)
- `frontend/src/components/Chat.tsx` line 686: `{loading && (activityStatus != null || !streamingContent) && (`
- `frontend/src/components/Chat.tsx` line 697: `{activityStatus ?? "Thinking..."}`
- `frontend/src/components/Chat.tsx` line 204: `setActivityStatus(formatToolActivity(toolName))` — called by `onActivity` callback

### 2. WebSocket client receives event
- `frontend/src/api/client.ts` line 350: `if (data.type === "tool_activity") this.onActivity?.(data.tool_name)`

### 3. Server sends ToolActivity over WebSocket (WIRED CORRECTLY)
- `server/src/http/ws.rs` line 251-254: activity callback sends `WsResponse::ToolActivity { tool_name }`
- This callback is passed to `chat::chat()` as the `on_activity` closure

### 4. chat::chat passes callback to Claude Code provider
- `server/src/llm/chat.rs`: passes `on_activity` through to `claude_code::chat_stream`
- `server/src/llm/providers/claude_code.rs` line 47: `mut on_activity: A` parameter
- `server/src/llm/providers/claude_code.rs` line 70: creates internal `activity_tx` channel
- `server/src/llm/providers/claude_code.rs` line 94: drains channel and calls `on_activity(&name)`

### 5. PTY event processing (SUSPECTED FAILURE POINT)
- `server/src/llm/providers/claude_code.rs` line 327: `process_json_event()` dispatches parsed JSON
- Line 348-353: matches `"stream_event"` type → extracts inner `event` → calls `handle_stream_event()`
- `server/src/llm/providers/claude_code.rs` line 486: `handle_stream_event()` matches on event type
- Line 494-500: matches `"content_block_start"` with `content_block.type == "tool_use"` → sends to `activity_tx`

### 6. The problem
`handle_stream_event` only matches `content_block_start` — this is the **raw Anthropic streaming API format**. But Claude Code's `--output-format stream-json` may NOT emit raw Anthropic events wrapped in `stream_event`. It likely uses its own event types for tool calls (e.g. `tool_use_begin`, `tool_use`, or similar).

The existing `process_json_event` also matches `"assistant"` (line 355) and `"user"` (line 363) event types from stream-json, but these are complete messages — they arrive after the tool call is done, not when it starts. So there's no event being caught at tool-call-start time.

## Investigation Steps

1. Add logging in `process_json_event` (line 334) to print every `event_type` received from the PTY during a chat session with tool use
2. Identify which event type Claude Code emits when it starts a tool call
3. Add matching for that event type to fire `activity_tx.send(tool_name)`

## Key Files
- `server/src/llm/providers/claude_code.rs` line 327: `process_json_event` — event dispatcher
- `server/src/llm/providers/claude_code.rs` line 486: `handle_stream_event` — only handles Anthropic API format
- `server/src/http/ws.rs` line 251: activity callback wiring to WebSocket
- `frontend/src/components/Chat.tsx` line 203: `onActivity` handler that sets display state

## How to Reproduce

1. Rebuild both frontend and backend from master (which includes story 86 and bug 140)
2. Open web UI chat
3. Send a message that causes tool use (e.g. ask agent to read a file)
4. Watch the activity indicator

## Actual Result

Indicator always shows "Thinking..." and never changes to tool activity labels like "Reading file..." or "Executing command..."

## Expected Result

Indicator should cycle through tool activity labels as the agent calls tools

## Hints for the Coder

- **Check external docs**: The Claude Code CLI `--output-format stream-json` format may be documented at https://docs.anthropic.com or in the Claude Code repo. Search for the actual event schema before guessing.
- **Add logging as an intermediate step**: If unsure about the event format, add a `slog!` or `eprintln!` in `process_json_event` (line 334) to log every `event_type` received. Rebuild, run a web UI chat with tool use, and inspect the output to see exactly what events arrive.
- **Run the CLI directly**: You can run `claude -p "read /etc/hosts" --output-format stream-json` in a terminal to see the raw stream-json output and identify the event types for tool calls.
- **Don't assume the Anthropic API format**: The existing `content_block_start` matching was likely copied from the Anthropic provider. Claude Code's stream-json is a different format.

## Acceptance Criteria

- [ ] Activity indicator shows tool names (e.g. "Reading file...", "Executing command...") when the web UI agent calls tools
- [ ] Indicator still falls back to "Thinking..." when no tool activity is in progress
- [ ] Works for all tool types (Read, Write, Bash, Glob, Grep, etc.)
