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

Annotations already declare destructiveHint=true and non-idempotent behavior, and the description adds the crucial mechanic that it sets the end time from now and can shorten a lease if the supplied timeout is shorter than the remaining time. It also notes expired leases are skipped, though it does not cover partial failures or authentication details.

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 a single sentence that front-loads the purpose and includes the key edge case. It does not redundantly restate 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?

With rich schema descriptions and an explicit destructive annotation, the description supplies enough behavioral context for correct invocation. It stops short of explaining batch/partial-result behavior or errors for expired leases, which would matter for a mutating bulk operation.

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 coverage is 100%, so the baseline is 3, but the description adds meaningful semantics for visibility_timeout_seconds: it is a new absolute end offset from now, not an extension increment, and can reduce remaining time. The queue, lease list, and instance_id parameters are fully documented in 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 the core effect precisely: leases that have not expired get a new end time of now plus visibility_timeout_seconds. It clearly concerns queue lease duration rather than claim/ack/nack siblings, though it never explicitly names an alternative.

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 phrase 'More time for long work' implies the use case, but there is no explicit when-not guidance or comparison to queue_claim, queue_ack, or queue_nack. An agent must infer that it applies only to already-claimed, unexpired leases.

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