Guard the Context Window

Portability (required)

This skill is part of the portable pstack pack.

1. Read the pstack capability contract and the adapter for the active coding agent before any helper delegation.
2. Prefer capability verbs (explore, implement, review, parallel, ask_user, verify, model_role) over vendor tool names.
3. Resolve models through model_role. Never require a vendor-specific model identifier.
4. When helper spawning is unavailable, run the work on the lead agent and state that fan-out was collapsed.

The context window is finite and non-renewable within a session. Every token that enters should earn its place.

Why: Context overflow degrades reasoning quality, creates compression artifacts, and halts progress. Unlike compute or time, context spent inside a session cannot be reclaimed.