Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Despite good annotations, the description adds substantial behavioral context: BYO mode is deterministic/offline, BM25 mode is a lexical baseline with no neural evaluation, the NVIDIA endpoint was retired on 2026-05-18, and the API key 'transits RAM for the single call, never stored.' This fully discloses side effects and state implications beyond the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is structured as a numbered list with a front-loaded purpose. It is detailed but every sentence earns its place, including context like the NVIDIA retirement date and key-storage behavior. No filler or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has three distinct execution modes, CI-gating semantics, and a historical deprecation caveat, all fully explained. Output schema exists, so return-value documentation is not required here. The description is complete for the tool's complexity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds meaningful semantic guidance: score must be present on every passage or none, api_key is used only when no passage carries a score, and higher scores mean more relevant. These details connect the parameters to mode selection in a way the schema alone does not.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Evaluate RAG retrieval quality: rank passages against a query and compute Precision@k / Recall@k plus a PASS/FAIL CI verdict.' It clearly differentiates three modes and is distinct from sibling tools like rag_relevance_rank or bm25_score by emphasizing ground-truth evaluation rather than mere ranking.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives explicit when-to-use guidance for each mode: BYO scores is 'the mode to gate CI on', BM25 mode answers a specific keyword-floor question and 'never is my neural reranker good', and the live NVIDIA mode is restricted to grandfathered accounts with reranking entitlement. This is exemplary usage differentiation.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.