compress

name	compress
description	Compress the session conversation when context approaches the limit.
argument-hint	[--tokens-before=<n>] [--tokens-after=<n>] [--runtime=<id>]
user-invocable	true
disable-model-invocation	false

/compress

Canonical algorithm

1. Read tokens_before (required; missing/zero degrades to status=needs_user) and tokens_after (defaults to a no-op when omitted; clamped so a pass can only shrink the context).
2. Build the per-runtime compression directive (cache-control wiring) for the target runtime (defaults to claude-code, the only runtime with a caller-side cache-control marker). An unknown runtime degrades to status=needs_user.
3. Append the canonical compression_emitted event carrying the token deltas and the realised ratio so the telemetry projector can chart context pressure over a session.

The model summarisation fan-out lives behind the runtime adapter's cache-control hook; the skill records the requested compression.

Pre-flight checklist

• tokens_before is present and > 0.
• The target runtime is a known runtime id.

Decision surfaces

A missing/zero tokens_before or an unknown runtime degrades to status=needs_user, which routes the operator to an AskUserQuestion prompt for the missing input rather than emitting a compression event against an unresolved runtime.

Output contract

Skill envelope with header.skill = "/compress". Body carries tokens_before, tokens_after, ratio, runtime, and cache_control_applied.