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

With annotations declaring readOnlyHint=true, the description adds significant context beyond that: it discloses the tool is cheap and has no embedding, mentions the specific content covered (result modifiers, invokeNative vs invokeNativeByHash, type mapping, pointer-arg gotchas), and tells the user to call it only once per session. This goes well beyond the structured 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 four sentences, each with a distinct purpose: purpose, usage timing, content scope, and cost/behavior. It is front-loaded with the core action and contains no redundant phrases or filler.

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?

Given the tool has only one parameter and no output schema, the description provides comprehensive context: what it does, when to use it, why it's needed, what it covers, and its low cost. It fully prepares an agent to select and invoke the tool correctly.

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?

The schema covers the only parameter (language) with a clear enum and description, so the baseline is 3. The description mentions 'in `js` or `lua`' which mirrors the enum but doesn't add new semantic details beyond what the schema already provides.

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 clearly states the tool loads a 'calling-convention reference for RedM/RDR3 natives' in a specific language, which is a specific verb+resource. It distinguishes itself from sibling tools like lookup_native or get_document by emphasizing that it is the translation guide for JS/Lua authors, addressing a unique gap in the documentation.

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 explicitly says 'Call ONCE per session before writing native-calling code', providing clear when-to-use guidance. It explains why this tool is needed (every native doc page only shows Lua examples) but does not explicitly name alternatives or say when not to use it, so it doesn't reach a 5.

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