Session Timeline Skill for Claude

Session Timeline

Reconstruct the chronological event timeline of a single Claude Code session.

Input

The user provides: $ARGUMENTS

• A session ID to time-line, or
• "latest" / "last" for the most recent session.

Data Sources

| Endpoint | Returns |

|----------|---------|

| GET /api/sessions/:id | session header: status, model, cwd, started_at, ended_at, cost, metadata (thinking_blocks, turn_count, total_turn_duration_ms) — and nested events |

| GET /api/events?session_id=X | the full event stream: event_type (PreToolUse, PostToolUse, Stop, SubagentStop, SessionStart, SessionEnd, Notification, Compaction, APIError, TurnDuration), tool_name, summary, data, timestamp |

Report Sections

1. Resolve & header

If "latest", GET /api/sessions?limit=1 to get the id, then GET /api/sessions/:id.

Print a one-line header: id, status, model, cwd basename, started_at → ended_at,

turn_count, total_turn_duration_ms, cost.

2. Build the ordered timeline

GET /api/events?session_id=X. Sort strictly by timestamp. For each event emit a

row with: relative offset from started_at (e.g. +00:03.412), event_type,

tool_name (when present), and a one-line summary.

3. Compute durations

Pair each PreToolUse with its matching PostToolUse (same tool_name, next

occurrence) and show the tool's wall-clock duration. For TurnDuration events use

the recorded duration directly. Flag any PreToolUse with no matching PostToolUse

as unclosed.

4. Annotate notable points

Mark APIError (❌), Compaction (⚠️ context compressed), SubagentStop

(subagent finished), Notification (ℹ️), and any timeline gap > 30s between

consecutive events as an idle window.

5. Tallies

Event count by type, total tool time vs. session wall time, and the longest single

tool call.

Output

A Markdown table — offset | event_type | tool_name | duration | summary — in

strict timestamp order, preceded by the header line and followed by the tallies.

Durations in ms or mm:ss.mmm; currency as USD to 4 decimal places. Never invent a

duration when a PostToolUse is missing — label it unclosed. If the dashboard is

unreachable, tell the user to start it with npm start from the repo root.