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

Annotations already declare destructiveHint=true and idempotentHint=true, so the deletion profile is covered structurally. The description adds genuine non-obvious behavior: leases that expired and were re-claimed appear in a "lost" list, which is not derivable from annotations or schema.

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?

Two short sentences with no waste. It is slightly weakened by the odd front-loaded "Done:" framing, which reads as a return-value note rather than a front-loaded statement of purpose.

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 no output schema, the mention of the "lost" list usefully documents part of the return value, and annotations cover the destructive/idempotent profile. Still, nothing is said about failure modes (e.g., invalid or already-acked leases) or what a successful ack returns beyond the lost case.

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 100%, so the schema already documents queue, leases, instance_id, and passport_token. The description adds no format, limit, or origin detail beyond what the schema states, so the baseline 3 applies.

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 effect of the operation ("the messages of these leases are deleted"), which lets an agent infer that acknowledging removes messages. However, it is phrased as a response summary ("Done:") rather than a description of what the tool does, and it never distinguishes queue_ack from siblings like queue_nack, queue_claim, or queue_dead.

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?

There is no guidance on when to acknowledge versus nack, extend, or requeue a lease. No prerequisites or conditions are stated, so the agent must infer usage entirely from the queue_* naming family.

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