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

Annotations only indicate readOnlyHint=false and destructiveHint=false. The description goes well beyond that, disclosing the domain separation for signatures ('distinct from the read and release domains'), the 'unlimited distinct keys per wallet' constraint, the renewal property, and the exact mechanism to obtain the signing message (placeholder signature triggers details.expected). It does not describe response structure, but the annotations already cover the safety profile, so the added context is valuable.

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 long (~220 words) and front-loads the core purpose, but then drifts into tangential material: complaints, questions, quote requests, and the feedback endpoint, which are unrelated to tool invocation. While some extra context (domain separation, signature flow) is valuable, the marketing-style filler significantly hurts conciseness. It could be trimmed by half without losing critical guidance.

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 5-parameter, all-required tool with no output schema, the description covers the acquisition process, signature retrieval, duration, and renewal. However, it never describes what a successful response looks like (e.g., lock metadata, expiry timestamp), which an agent would need to know to confirm success. It also omits any rate limits or quotas beyond 'unlimited distinct keys.' Given the tool's moderate complexity, a 3 reflects the gap in response semantics but acknowledges the strong coverage of the invocation flow.

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 covers all 5 parameters with clear descriptions (100% coverage), so the baseline is 3. The description adds one useful nuance for the signature parameter (the placeholder-signature trick to retrieve the message), but this is more about the overall flow than parameter meaning. It does not materially improve understanding of any parameter beyond what the schema already states.

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 opens with a clear, specific action: 'win a caller-named key for 300 seconds, or learn who already holds it.' This states the verb (acquire), the resource (named key), and the duration (300 seconds). It also explicitly distinguishes itself from the sibling claim_acquire, calling it 'not a discount on it' and contrasting the lease length, so an agent can tell them apart without opening schemas.

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 gives explicit when-to-use guidance: 'this lease is 12x shorter than the cheapest paid plan, so a lock that has to survive a deploy, a batch or a day is on the paid ladder from the first minute.' It names the alternative (claim_acquire) and the condition that selects it (duration need), plus notes renewability. This is direct, actionable guidance with no ambiguity.

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