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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the mutation risk is known. The description adds a genuine requirement beyond annotations, the 'repo' scope, plus the state precondition, but says nothing about irreversibility, what happens to in-flight jobs, or whether logs are retained.

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, zero filler, with the action and target front-loaded ahead of the scope prerequisite.

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 destructive three-parameter mutation with no output schema, the definition covers the action and auth scope but leaves the agent guessing about side effects on running jobs and the result of the call. Adequate but with clear gaps.

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 only 33%: run_id is well documented (including the '8+ hex characters' prefix-matching rule), but owner and repo have no schema descriptions. The description does not compensate at all, adding no meaning for any of the three required parameters.

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 narrows the target to runs that are queued or running. It is clearly distinct from read-oriented siblings such as merjax_get_workflow_run and merjax_list_workflow_runs, though no sibling is named explicitly.

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 'queued/running' implies the applicable precondition, but there is no explicit when-not guidance (e.g. already-completed runs cannot be cancelled) and no routing to likely alternatives like merjax_prioritize_workflow_run or merjax_rerun_failed_jobs.

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