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

Annotations only declare the generic profile (not read-only, not destructive, closed world); the description adds the operationally critical details: it returns a private leaseToken with a 10-minute lifetime, plus plan and checkpoint. It also states a security constraint (never surface the token to the client) and a lease prerequisite, which is exactly the kind of behavior an agent cannot infer from structured fields.

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?

Five short sentences, front-loaded with the trigger condition, then the return contract, then the safety prohibitions. No filler; every clause adds a constraint or a fact the caller needs.

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 lease-claiming mutation with no output schema, the description covers the return payload, its expiry, and the safety rules, which is the bulk of what matters. Gaps remain around failure modes (what happens on version mismatch or a still-valid lease) and whether/how the lease is released, but the essential contract is present.

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 0%, so the description must carry all three parameters, but it only gestures at 'version' via 'Version courante requise' (optimistic concurrency). Neither 'id' (the collection identifier) nor 'worker' (the claiming worker identity) is explained anywhere, leaving two of three required parameters undefined.

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+resource ('Prendre en charge une collecte') plus the exact state predicate that qualifies it (queued or running with an expired lease). That predicate is what separates it from siblings like claim_task, claim_browser_tasks, or get_collection, so an agent can route without opening any 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?

Gives clear preconditions for use – the collection must be queued/running, the lease must have expired, and the current version is required – plus a hard prohibition ('Ne pas exécuter sans bail'). It stops short of naming an alternative tool for the case where the lease has not expired, so the negative case is implied rather than routed.

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