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

Annotations declare readOnlyHint=false and destructiveHint=false, so the safety profile is already covered; the description usefully adds that authentication is required and how to obtain a session. It still omits behaviorally relevant details for a mutation: how much the expiration is extended, whether there are limits or one-shot restrictions, and what happens if the request is no longer pending.

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 core action is front-loaded in the first sentence, and the auth instructions follow as a clearly separated paragraph. It is slightly verbose for a one-parameter tool, but every sentence carries operational information rather than 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?

There is no output schema, so the description should ideally hint at the result of the extension, and it does not. The auth prerequisite is fully covered, but the agent still lacks detail on extension magnitude and edge cases for this mutation, leaving it minimally adequate.

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 description coverage is 100% and the sole parameter 'id' is documented in the schema as 'Verification request ID to extend', so the description cannot add much. It contributes no format, source, or lookup guidance for obtaining the ID, so baseline 3 applies.

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 and resource ('Extend the expiration time of a pending verification request'), which pinpoints the operation precisely. It doesn't name a sibling alternative, but the mutation semantics and the 'pending' qualifier make the target object unambiguous against the large sibling set.

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 ACCESS paragraph gives concrete operational prerequisites (Proof account, authenticate via /mcp, or start_login) and even notes that start_login opens a session, which is genuine usage context. However, it never says when to extend versus when to cancel or recreate a request, e.g. how it relates to cancel_verification_request.

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