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

Annotations already declare destructiveHint=true and readOnlyHint=false, but the description adds genuinely useful context that annotations cannot: this is a soft delete, the request stays visible with status 'cancelled', and downstream operations (update, decompose, publish) are blocked. That materially refines the meaning of 'destructive' for the caller. It does not disclose permissions or idempotency behavior.

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?

Three short sentences, action first, consequences second, semantic clarification third. No filler, and the most important information (what the tool does) is front-loaded.

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 one-parameter, no-output-schema tool with destructive annotations, the description covers purpose, irreversibility of downstream actions, and the soft-delete semantics. Only minor gaps remain, such as required request status or whether cancel is idempotent, which an agent could reasonably need.

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?

There is a single parameter with 100% schema description coverage ('Request ID to cancel'), so the schema fully documents the input. The description adds no format, sourcing, or validation guidance beyond it. 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 (Cancel) and resource (capability request) in the first sentence, and the second sentence implicitly distinguishes it from the sibling mutation tools pcc_update_request, pcc_decompose_request, and pcc_publish_request by naming the operations that become impossible. It stops just short of explicitly naming an alternative tool or the trigger condition for choosing it.

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?

Usage is implied rather than stated: an agent can infer this is for terminal withdrawal of a request, and that update/decompose/publish are no longer options afterward. However, there is no explicit 'use this when X, instead of Y' guidance, no prerequisites (e.g. must the request be in a particular status?), and no statement about whether cancellation can be repeated or undone.

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