Variable MEDIA_BUY_TOOLSConst

Known AdCP tool names for protocol detection. These map to task names in the AdCP schema index (kebab-case -> snake_case).

Note: Some tools appear in multiple arrays (e.g., list_creative_formats is in both MEDIA_BUY_TOOLS and CREATIVE_TOOLS). This is intentional — these tools serve multiple domains, and their presence should activate all relevant protocols when detectProtocols() runs.

Why these aren't manifest-derived (#1192). The AdCP manifest (schemas/cache/{version}/manifest.json) carries a single primary protocol per tool — list_creative_formats is media-buy there, never creative. That's an authoring convenience (where does the tool's spec page live), not a capability-declaration semantic. The cross-listing here captures operator reality: a CMP that exposes only build_creative / list_creative_formats / sync_creatives IS a creative agent, and a buyer discovering it via tools/list should see the creative protocol family. Migrating to manifest-primary would silently flip detectProtocols() results for cross-listed tools and break CMP↔DSP discovery flows. The drift guard at test/lib/capabilities-tools-drift.test.js keeps the arrays locked to recognized manifest tools (catches typos and removed-upstream tools) without forcing the arrays to match the manifest's single-valued view. See PR #1298 for the design rationale.