event-trace

1# Event Trace
2 
3Build a chronological, annotated event timeline for a single session.
4 
5## Input
6 
7The user provides: **$ARGUMENTS**
8 
9This is a session ID. It may also be:
10- `latest` / `last` — trace the most recently updated session
11- `errors` — trace the most recent session whose status is `error`
12 
13## Data Sources
14 
15| Endpoint | Returns |
16|----------|---------|
17| `GET /api/sessions?limit=N` | session list (used to resolve `latest`/`errors` and the target id) |
18| `GET /api/sessions/:id` | full session detail (status, model, cwd, started_at, ended_at, cost, nested agents + events) |
19| `GET /api/events?session_id=X` | the ordered event stream: event_type, tool_name, summary, data, timestamp |
20 
21## Report Sections
22 
23### 1. Resolve the session
24If `$ARGUMENTS` is a raw id, use it. If `latest`/`last`, call
25`GET /api/sessions?limit=1`. If `errors`, call
26`GET /api/sessions?limit=10&status=error` and pick the newest. Confirm the id
27resolves via `GET /api/sessions/:id`; if not, report it as missing and stop.
28 
29### 2. Session header
30From `GET /api/sessions/:id`: id, status, model, cwd, started_at → ended_at,
31total duration, cost (USD to 4 decimals), and counts (events, agents).
32 
33### 3. Ordered timeline
34From `GET /api/events?session_id=X`, list every event in timestamp order. One row
35per event:
36 
37`| # | time | Δ since prev | event_type | tool_name | summary |`
38 
39Cover all event types present: SessionStart, PreToolUse, PostToolUse, Stop,
40…