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

With annotations already indicating this is not read-only and not idempotent, the description adds meaningful behavioral context by stating that completed steps are not rolled back. This warns the agent that cancellation is not a full undo, which is valuable beyond the structured annotations.

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, no filler, and the core action is front-loaded. Every sentence adds useful information about scope or side effects.

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 tool with complete schema coverage and a clear action, the description is nearly sufficient. It could mention the behavior when the run is already completed or already canceled, but the current wording gives enough guidance for correct invocation.

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 runId already described as 'UUID of the run to cancel.' The description adds no further parameter-level meaning, so the schema carries the weight and a baseline 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?

The description uses a specific verb ('Cancel') and a specific resource ('running or waiting flow execution'), and it narrows the scope to actionable states. It clearly distinguishes this tool from flow-related tools like neuron_run_flow, neuron_get_flow_run, and neuron_list_flow_runs.

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 'running or waiting' provides clear context for when the tool applies, and the no-rollback note implies it should not be used when preserving completed step effects matters. It does not explicitly name alternative tools, but the intended condition is clear enough.

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