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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint false, and destructiveHint false. The description adds that the endpoint is public, that it returns an exact signing string, and that it was formerly GET /contracts/:id/statement, which are useful behavioral details 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?

The description is dense but front-loaded, starting with the key output and then covering nonce source, action semantics, workflow, and legacy naming. Every sentence contributes operational context without filler.

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 four-parameter, no-output-schema tool, the description supplies the missing return-value context ('EXACT string'), the required nonce workflow, action distinctions, signing sequence, public status, and legacy endpoint. Nothing essential for correct invocation appears absent.

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 already 100%, so the baseline is 3. The description adds semantic meaning for the action parameter by explaining that sign covers immutable terms and their hash, while terminate needs agent_id, going slightly beyond the schema's default-sign note.

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 immediately states that this returns the EXACT string a party signs for a membership, which is a precise verb-and-resource outcome. It also names the related tools sign_membership and terminate_membership, so an agent can distinguish this retrieval step from the actual signing or termination actions.

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 explains the workflow: obtain a fresh nonce via POST /agents/:id/challenge, sign the returned string with your own Ed25519 key, then call sign_membership or terminate_membership. This explicitly tells the agent when to use this tool versus its signing siblings.

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