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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description contributes real extra context: only in-progress runs are affected, the caller needs manage permission, and the feature requires a PRO+ plan.

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 front-loaded, then the eligibility constraints. Nothing is padded and no sentence is redundant.

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 destructive tool with full annotation and schema coverage, the description covers scope, permissions and feature gating adequately. It omits what happens after cancellation (reversibility, effect on running tasks), which is a minor gap rather than a blocking one.

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, so the schema fully documents runId. The description adds no format, source, or lookup guidance for the ID, and per the high-coverage baseline a 3 is appropriate.

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 and resource ('Cancel an in-progress workflow run') and constrains scope to in-progress runs, which cleanly separates it from list_workflow_runs and get_workflow_run. It does not name a sibling explicitly, so it falls short of the top band.

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?

Adds a permission prerequisite ('caller must be able to manage the workflow') and a plan gate ('automations (PRO+)'), which tells the agent when the call will succeed. However, it never contrasts this with alternatives such as decide_workflow_approval or test_run_workflow, so usage is only implied.

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