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

Annotations only declare destructiveHint=true and readOnlyHint=false, which do not reveal that the run's recorded route and measurements survive the operation. That preservation guarantee is real added context not available in structured fields. It leaves out reversibility and post-cancel state, keeping it below 5.

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 sentences, no filler, with the key non-obvious fact (data is preserved) front-loaded ahead of the requirement reminder. Nothing to trim.

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 two-parameter mutation with no output schema, the description covers the essential outcome difference from deletion. It omits what state the run ends in, whether the action is reversible, and any error/failure conditions, which would round it out.

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%, with both runId and reason documented in the schema itself, so the baseline is 3. The description's 'a truthful reason is required' restates the schema's own wording rather than adding format or constraint 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 specific verb (cancel) and resource (workflow run), and adds a scoping clause ('without deleting its recorded route or measurements') that behaviorally separates it from delete_workflow. It does not name that sibling explicitly, so it stops short of a 5.

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 'open workflow run' implies a precondition (only open runs are cancellable), which is useful implied guidance. However, there is no explicit when-to-use guidance, no mention of resume_workflow as a related/opposite action, and no statement about what to do for already-completed runs.

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