agent_key_pin

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

With no annotations, the description carries full behavioral burden. It usefully discloses that the pin and comparison live server-side on the relay, that it warns on key change, and that it feeds the local credential store identity — but omits auth requirements, whether re-pinning overwrites, and whether a mismatch blocks or merely warns.

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 with the core action front-loaded. The trailing sentence about the local credential store is somewhat vague but does add identity context, so only minor waste.

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 one-parameter, no-output-schema tool this covers the essential purpose and the TOFU/warning behavior. It still leaves open what the caller should expect on mismatch and what permissions are needed, so it is adequate but not 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?

One parameter (did) with 100% schema description coverage, so the schema already documents it. The description adds no format or resolution detail beyond what the schema provides, which is the expected baseline here.

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: 'Pin another agent's public keys on the relay,' which is clearly distinct from the sibling agent_key_verify (verification) and agent_key_pins (listing). It does not explicitly name those siblings, so the differentiation is inferable rather than stated.

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?

'Trust on first use' implies the intended context (initial trust establishment) and 'warns if they changed' hints at the re-check case, but there is no explicit when-to-use versus agent_key_verify or when-not-to-use guidance.

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