delegating-with-context

Delegating with context

Writing a background brief for a subagent costs output tokens, generation time, and fidelity: exact paths, error strings and numbers get paraphrased or dropped, and the brief omits what the orchestrator did not know mattered. The context_hook.py PreToolUse hook removes the need. It reads the session transcript, asks Jev which chunks the task needs, and appends those chunks to the subagent's prompt verbatim. The hook fires after the prompt is written, so it cannot save a brief you already wrote. The saving happens here, before the tool input exists.

Procedure

1. Check the hook is live. test -s ~/.claude/context-filter-log.jsonl && tail -1 ~/.claude/context-filter-log.jsonl shows the last filtered delegation. No file on a first delegation is normal; the hook's reply after your first Agent call confirms it (step 5). Where the hook is not wired (claude.ai, a machine without the settings entry), stop here and write a normal brief.

2. Preview what the filter would pass. One call, all tasks at once:

   python3 /mnt/skills/user/delegating-with-context/scripts/preview.py \
     --task "Write the xr latency note for the follow-up memory" \
     --task "Draft the closing status for both PRs"
   

   Each task prints the kept chunk ids with a one-line gist. This is the check: find the chunk that holds the fact the subagent must not miss. It takes one to two seconds and costs a fraction of a cent.

3. Write only the task. What to do, the deliverable, its format, and any constraint that was never written down in the session. Name things the way the transcript names them ("the Sniff Test benchmark table", "PR #812"): Jev reads literally, and a named thing matches its chunk while "that thing we discussed" matches nothing.

4. Add only what the preview missed. If a needed fact is in no kept chunk, state that one fact in the prompt, or raise the budget with [context-budget: 40000] in the prompt text. Do not restate facts the preview already showed.