Stop a plan's parts

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

Beyond the annotations (readOnlyHint false, idempotentHint true, destructiveHint false), the description discloses two non-obvious behaviors: completed work is preserved and a partially executed part may already have been billed. That billing side effect is exactly the kind of consequence annotations cannot express. It loses a point for not saying what the response returns or whether a stopped part can be restarted.

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, with the core action front-loaded and the caveat about billing placed immediately after it. No filler, no restatement of the title or name.

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 mutation with rich annotations and no output schema, the definition covers the action, the persistence semantics and the billing risk. The only real gap is the absence of any statement about the return value or whether stopping is reversible.

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 only one parameter, and its schema description ("The plan's id, from plan.") already covers it at 100% coverage. The description adds nothing about the id's format or about what happens when the id refers to a plan that is not currently running, so baseline 3 applies.

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 ("Stop") on a specific resource ("the parts of a plan that Leanfare is running (plan_run)"), which lets an agent distinguish it from plan_status or plan_run. It stops just short of a 5 because "parts of a plan" is slightly ambiguous against the sibling 'plan' tool, which is the only other tool that could plausibly manage the same object.

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 description implies usage, namely cancelling in-flight execution of a running plan, but it never says when to pick this over plan_run, plan_status or plan. There are no stated prerequisites (for example, a plan must be running) and no exclusions, so the agent has to infer the trigger condition.

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