Context Budget Audit

Core principle: everything loaded at session start spends context before the user types a word. MCP tool schemas, skill descriptions, slash-command and subagent listings, enabled plugins — measure that spend from local disk evidence and report what to prune, biggest wins first. Audit and recommendations run to completion; the one stop is editing the user's harness config.

Invariants

• The engine is read-only; it never edits or deletes anything.
• An MCP server with no observed mcp__<server>__* tool calls is idle: cost unknown-but-likely-largest, never "~0 tokens". Surface idle servers first.
• Footprint vs reclaim: "descriptions compressed" warnings come from aggregate load (count × description length), not individual non-use — the levers are fewer loaded items and shorter heavy descriptions, not only deleting unused ones.
• Token figures are estimates; counts are evidence matches; "no evidence" means none in the scan window, not never used. Generic names (run, review) are weak evidence.
• Never quote raw transcript, prompt, or credential content — display paths, counts, timestamps, and classification reasons only.
• System skills (.system) and plugin/marketplace caches are inventory-only, never prune targets. Disabled plugins cost zero context — not reclaim candidates.
• Never remove a skill store copy without a validated repo copy; if copies differ, remove nothing and flag the difference in the report.

Workflow