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

Annotations cover idempotency and non-destructiveness, and the description corroborates them ('Releasing twice is harmless') while adding context they cannot carry: the outcome value also stamps the key so no separate mark call is needed, and the return payload is named. Nothing contradicts 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 core action is front-loaded, followed by requirements, side effects, return value, safety, and the alternative. Seven short sentences with essentially no filler, though the outcome/failure branch is slightly sprawling.

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 description supplies the return shape (release time, log entry number), the mutation side effect, the idempotency behavior, and the lost-token fallback. An agent has everything needed to invoke it or route away from it.

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 meaning beyond the schema: it ties the token to the claim call that issued it, links outcome to its side effect on the key, and notes that omitting outcome is fine. It stops short of adding syntax detail.

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 concrete verb and resource ('Last step for a lease you hold: ends it now') and immediately positions the tool against its sibling mark. An agent can distinguish release from claim/look/mark 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?

Explicit when-to-use (you hold a lease, you want others not to wait), when-not ('If you lost the token do nothing: the lease dies at its expiry'), and a named alternative with its selecting condition ('Use mark instead when you hold no lease and only want to leave a trace').

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