identity_jwks

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

With no annotations, the description carries the full behavioral burden, but the operation is a simple zero-parameter public-key fetch. It usefully discloses that the keys are public (no auth secret leaked) and 'Free' (no cost/paywall), yet says nothing about caching, key rotation, or response format.

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?

Two short fragments, front-loaded with the service name and resource, then the purpose and cost. Nothing is wasted, though the telegraphic style makes it slightly clipped rather than fully self-explanatory.

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?

For a zero-parameter, no-output-schema key retrieval, the description supplies enough to call it correctly: what it returns, why, and that it is free. The main omission is any hint about the response shape (standard JWKS), which an agent could reasonably assume.

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 tool takes zero parameters, so the baseline is 4. The description adds no parameter detail because none is needed, and the empty schema is consistent with the description.

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 resource returned (public RS256 keys) and the resource's purpose (verify an assertion_token locally). It distinguishes itself from other identity_* siblings, which handle nonces, registration, and challenges. It lacks an explicit verb like 'returns' or 'fetches', but the resource is unambiguous.

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 phrase 'to verify an assertion_token locally' implies the use case (offline token verification), which is a fair contextual hint. However, it does not state when to prefer this over server-side verification or reference any sibling tool, leaving usage to inference.

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