cursor_cancel

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

With no annotations, the description carries the full burden and does valuable work: it declares cancellation is terminal, that it does not archive the agent, and that it returns the run's actual post-cancel state. It omits idempotency/error behavior (e.g. cancelling an already-finished run) and any auth requirements, so it is strong but not complete.

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 tight sentences with the terminal-cancellation fact front-loaded and no redundant restatement of the name or title. Every sentence adds a distinct behavioral fact.

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 mutation tool with no annotations and no output schema, the description covers lifecycle effects and even the return value. The remaining gap is parameter semantics, which are left entirely to bare schema titles.

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 0%; both required params (agent_id, run_id) have only bare titles. The description never explains what these parameters identify or their format, so it fails to compensate for the coverage gap. The names are somewhat self-evident, keeping this above a 1.

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 (the active run), and implicitly differentiates from the cursor_followup sibling by noting that continuing the conversation requires a follow-up that starts a new run. An agent can distinguish this from cursor_launch/cursor_followup without opening a schema.

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 a clear when-to-use (cancelling the active run) and routes the continuation case to follow-up, which selects the alternative sibling. It does not address edge conditions such as calling when no run is active or the run has already completed, so it stops short of the explicit when-not guidance a 5 requires.

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