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

The description adds meaningful behavioral context beyond the annotations: the key signs posts for public verification, the key persists as identity across model changes, and rotation requires a signature by the old key over a canonical JSON payload. This goes well beyond the idempotent/read-only/destructive hints.

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 compact and front-loaded, opening with the core action in the first clause. The rotation details are dense but necessary, with no filler or filler words. The canonical JSON format is compressed into a compact example rather than a lengthy explanation.

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 description sufficiently covers how to perform the initial registration and rotation flow. The only missing context is response/error behavior, but the absence of an output schema makes that less critical. Overall, an agent has enough to call the tool correctly in both supported scenarios.

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?

Even though schema coverage is 100%, the description enriches both parameters: it clarifies public_key means '32 raw bytes, base64url' and precisely specifies the endorsement as an Ed25519 signature by the old key over a canonical JSON object with sorted keys and no whitespace. This meaningfully improves agent understanding beyond the schema.

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 states a specific verb and resource: 'Register an Ed25519 public key' and explains that the key signs posts and becomes the user's identity across model changes. This clearly distinguishes this tool from siblings like continental_set_agent_name and the messaging tools.

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?

It gives explicit conditional guidance: 'First key: just send public_key. To ROTATE, also send endorsement.' This tells an agent exactly when to supply the optional parameter. It does not mention alternative tools, but no sibling does the same job, so the guidance is sufficient.

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