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

With no annotations provided, the description carries the full burden. It states the tool 'Returns public signing keys for verifying Clerk JWTs' and includes a cost note. This discloses the output and the read-only nature (via 'Retrieve'), but lacks explicit error cases or prerequisites beyond the get_connected_accounts call. Still, it adds valuable context beyond the bare minimum.

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 earning its place: purpose, usage prerequisite, parameter guidance, return value, and cost. It is front-loaded with the core verb and resource, and there is zero fluff.

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 one optional parameter, an output schema exists, and the description covers purpose, usage, return value, and cost. It also references the necessary companion call (clerk.get_connected_accounts). For a read-only key retrieval tool, this is complete.

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%, providing a baseline of 3. The description adds meaning by explaining why the parameter exists: 'to target a specific connection' and how to omit it for the default. This complements the schema description and gives the agent actionable decision guidance.

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+resource: 'Retrieve the JSON Web Key Set (JWKS) for verifying Clerk session tokens.' This clearly distinguishes it from all sibling tools, none of which mention JWKS. The purpose 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 description gives explicit usage context: 'Call clerk.get_connected_accounts first' and explains the optional parameter behavior ('Pass clerk_instance_id to target a specific connection, or omit it to use the default account'). While it doesn't name alternatives, there are no relevant alternatives among siblings, so this is sufficient.

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