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

Annotations already declare destructiveHint=true and idempotentHint=false; the description reinforces this with 'It can't be taken back', which tells the agent the effect is irreversible. It also discloses the eligibility constraint (only still-waiting approvals you requested), which the annotations do not carry.

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 zero filler; the verb, resource and lookup key are front-loaded, and the irreversibility warning is tacked on at the end where it belongs.

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 single-parameter mutation with no output schema and annotations covering the safety profile, the description supplies the preconditions and the irreversibility warning. It could mention what happens if the approval is no longer pending, but nothing essential to correct invocation is missing.

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% and the schema already documents the id, including the r:<home>:<id> form for cross-home ids. The description only says 'by its id', adding no syntax or format detail beyond the schema, 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?

States a specific verb ('call off') and resource (an approval), plus two scope qualifiers: it must be one 'you or your person asked for' and 'still waiting'. That state-based scoping cleanly separates it from ask_approval, get_approval, list_approvals and reply_approval without needing to name them.

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 usage context ('for example when it is no longer needed') and two preconditions (the approval must be yours/your person's and still pending). It stops short of naming sibling tools as alternatives, but the conditions are specific enough to route the agent correctly.

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