agent_key_pin

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

With no annotations, the description carries the full burden. It discloses the TOFU mechanism, warning on key changes, and MitM detection. However, it does not specify the exact outcome when keys change (e.g., failure vs warning) or whether the operation is reversible.

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 a single, clear, front-loaded sentence containing all essential information with no wasted words. It is appropriately concise.

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 simple pinning operation with no output schema, the description covers purpose, mechanism, and a key warning. It does not explain return values, but the behavioral transparency is sufficient. Minor gap: no guidance on prerequisites or response format.

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 input schema already has 100% description coverage for both parameters (api_key and did). The description adds no additional meaning beyond what the schema provides, earning the baseline score of 3.

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 action ('Pin another agent's public keys'), the mechanism ('TOFU — Trust On First Use'), and a key behavioral feature (warns on key changes for MitM detection), distinguishing it from siblings like agent_key_verify.

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 implies usage (when you want to establish trust via key pinning) but provides no explicit guidance on when not to use or alternatives among siblings like agent_key_verify or agent_key_pins.

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