pr-review compression Sub 2: Pilot extraction (§5.3 MCP-Tool-Description Budget)

Context

This is Sub-issue 2 of Epic #10537 (Modularize pr-review-guide.md condition-gated audits). It executes the pilot extraction of the condition-gated §5.3 MCP-Tool-Description Budget Audit out of the monolithic pr-review-guide.md and into a dedicated reference file.

The Problem

The §5.3 audit is condition-gated (fires only when touching openapi.yaml) but currently lives inline in the monolithic pr-review-guide.md. This consumes token budget and attention span on every review cycle, even though the trigger condition is met rarely (empirical 17% trigger rate).

The Fix

Extract the content of §5.3 into .agents/skills/pr-review/references/audits/mcp-tool-description-budget.md. Replace the inline §5.3 content in pr-review-guide.md with a one-line gate referencing the new file.

Acceptance Criteria

• Extract §5.3 to .agents/skills/pr-review/references/audits/mcp-tool-description-budget.md
• Replace inline §5.3 content in pr-review-guide.md with a one-line gate
• Ensure the extraction is covered under a valid PR (currently #10613)

Out of Scope

• Modifying other condition-gated audits (Sub-issue 3/4)
• Gathering the baseline metrics (completed in Sub-issue 1 #10540)

Related

• Epic: #10537
• Sub-issue 1 (Baseline): #10540
• PR: #10613

Origin Session ID: ba7c6393-6378-4905-bf62-12eca4954583 Retrieval Hint: query_raw_memories(query="pr-review pilot extraction §5.3 MCP-Tool-Description Budget")