Capture session

Skill honerlaw/agent-marketplace/plugins/utils/skills/capture-session

A personal plugin marketplace for AI coding agents. Each plugin provides skills and automation scripts.

Install

npx -y skills add honerlaw/agent-marketplace --skill capture-session

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What its author says it does

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Use when the user wants to analyze or record token/cost usage from a Claude Code session they just ran, in any repo. Finds the most recent transcript, runs the cost analyzer, and optionally records to the benchmark baseline.

SKILL.md

2.6 KB, 639 tokens by cl100k_base, as published. Nobody here has run it

Capture Session

Analyze and optionally record context usage from any completed Claude Code run.

Step 1 — Find the transcript

List the 10 most recently modified session transcripts across all projects:

ls -t ~/.claude/projects/*/*.jsonl 2>/dev/null | head -10

If the user mentions a specific repo, scope it. Encode the path by replacing / with -:

# e.g. /Users/foo/Development/my-repo → -Users-foo-Development-my-repo
ls -t ~/.claude/projects/-Users-derekhonerlaw-Development-<repo-name>/*.jsonl | head -5

Pick the most recently modified file. Confirm with the user if it's unclear which run they mean.

Step 2 — Analyze it

python3 /Users/derekhonerlaw/Development/agent-marketplace/scripts/run_analyzer.py <transcript.jsonl>

Show the user the full JSON output. Call out:

total_cost_usd — derived cost
totals — breakdown of all five token classes (input, output, cache-write-5m, cache-write-1h, cache-read)
by_model — per-model cost split
num_subagent_messages — how many subagent turns fired
by_tool — tool call counts

Step 3 — Record to baseline (optional)

Ask the user if they want to record this run to benchmarks/baseline.jsonl for comparison. If yes, ask for a short task-id label (e.g. psa-add-feature, debug-run-1).

Interactive session (most common): No result.json exists. Write a stub and record:

echo '{"session_id": "unknown", "total_cost_usd": null, "num_turns": null}' > /tmp/_session_stub.json
python3 /Users/derekhonerlaw/Development/agent-marketplace/scripts/run_benchmark.py record \
  --result /tmp/_session_stub.json \
  --transcript <transcript.jsonl> \
  --task-id <label>

cost_crosscheck_ok will be false (no claude -p result to cross-check against) but token counts are exact.

Headless session (claude -p --output-format json): The user has a result.json. Pass it directly:

python3 /Users/derekhonerlaw/Development/agent-marketplace/scripts/run_benchmark.py record \
  --result <result.json> \
  --transcript <transcript.jsonl> \
  --task-id <label>

Compare two recorded runs

python3 /Users/derekhonerlaw/Development/agent-marketplace/scripts/run_benchmark.py diff \
  --task-id <label>

Prints the delta (cost, tokens, turns, subagents) between the two most recent records for that task id.