Cancel a run

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

Goes well beyond the annotations: it discloses the required key scope with the exact error code (launch-level agent key, else 403 AGENT_LEVEL_INSUFFICIENT), what side effects occur (compute teardown of EC2/Celery/Batch resources), and the terminal-state conflict behavior (409). Annotations only say destructive=true and idempotent=true; the description supplies the operational consequences and failure modes.

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?

Four short lines, each front-loaded with a distinct fact: auth requirement, valid states, side effects, and failure code. No restatement of the title or name and nothing decorative.

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-param destructive mutation, it covers permissions, preconditions, side effects, and error responses, and an output schema already handles return values. Nothing an agent needs to invoke it safely and predict failure is missing.

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?

Only one parameter (run_id) and the schema already documents it at 100% coverage. The description adds no format, sourcing, or lookup guidance for run_id beyond the schema, so it sits at the baseline for high-coverage schemas.

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-flight simulation run') and scopes it narrowly with 'in-flight', implicitly separating it from get_run, get_run_status, list_runs, and retry_run. An agent can tell immediately this is the termination path, not a status or retry path.

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?

Gives explicit eligibility ('built, queued, or computing status') and an explicit when-not ('409 if the run is already in a terminal state'). It stops short of naming a sibling alternative (e.g., retry_run for failed runs or get_run_status to check state first), so it is clear context without full routing guidance.

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