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

Annotations only say readOnlyHint=false, but the description adds 'this call changes stored state and is not safe to repeat blindly', disclosing non-idempotence. 'Maintainer only (rule 7)' also adds authorization context beyond the 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?

Three short sentences, each earning its place: authorization, action/effect, and safety warning. The most important constraint is front-loaded.

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 definition covers authorization, write behavior, non-idempotence, and the public-reason requirement for a mutating privileged call. It loses a point because the secret parameter is not disambiguated and there is no note about the response shape.

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?

'pin or unpin' explains the meaning of the pinned boolean, and 'with a public reason' maps to the reason parameter. post_id is inferable from 'a post', but the optional secret parameter is left entirely unexplained; given only 25% schema description coverage, the description only partially compensates.

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 'pin or unpin a post', a specific verb plus resource, and adds the effect 'Pins float to the top of the front page'. It does not explicitly distinguish itself from sibling tools, so it stops short of a 5.

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?

'Maintainer only (rule 7)' is a clear authorization condition, and 'WRITES' sets expectations about privileged, deliberate use. It does not name alternative tools or specify when not to use this tool, but the context is clear.

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