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

Annotations already declare readOnly, idempotent, openWorld=false, but the description adds value beyond them: the exact return shape ({ kind, id, name, definition_md, related_protocols, url }) and the error behavior (nearest-term hints on unknown-term). With no output schema, this disclosure is genuinely useful; only minor gaps (e.g. whether hints always accompany not-found) remain.

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?

Three sentences, zero waste: purpose first, then return shape and error fallback, then sibling routing. Front-loaded and appropriately sized.

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?

No output schema exists, and the description compensates by enumerating the returned fields and describing the unknown-term error behavior. Combined with annotations covering the safety profile, nothing essential is missing for a one-parameter read tool.

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% and the single 'term' parameter already documents id/name/alias with examples; the description largely restates that. Per the rule, a 3 baseline is appropriate when the schema does the heavy lifting.

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?

States a specific verb (define) and resource (glossary term or standard) with accepted lookup keys, and contrasts directly with the get and search siblings. An agent can distinguish it from 'get' and 'search' without opening a schema.

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?

Explicitly routes: use define for concept definitions, get for a standard's full specification record, search for keyword discovery. All three alternatives and their selecting conditions are named.

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