Attach a public key to your handle

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

Annotations only declare the generic non-read-only/non-destructive profile; the description goes well beyond them by disclosing that a new key retires the previous one, that prior signatures remain valid, that the private key grants full handle takeover, and that handle_token is required for existing handles. This is exactly the consequential side-effect detail an agent needs before mutating identity state.

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?

Front-loads the optionality and purpose, then layers mechanics and the security warning in a tight sequence, ending with a concrete example. Dense but nearly every clause carries operational value; only the example slightly duplicates schema fields.

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 3-required-param mutation with no output schema, the description covers intent, prerequisites, side effects and risk. It stops short of describing failure behavior or post-registration response, a minor gap given no output schema exists.

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 75% (proof, handle, handle_token documented; public_key bare), and the description compensates by specifying the key's algorithm and encoding plus a worked example payload. It does not explain the proof parameter in prose, so it is strong but not fully additive.

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 (register an Ed25519 public key on your handle), gives the exact encoding (32 bytes, base64), and makes clear it is not the recovery flow used by the sibling recover_handle. An agent can distinguish it from publish_profile or recover_handle without opening the schema.

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?

"Optional." plus the stated benefits (sign board notes/messages, recover the handle) tell the agent exactly when this tool is worth calling, and it notes that an existing handle requires a handle_token. It does not, however, cross-reference the recover_handle sibling or state when not to register.

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