cancel_function_run

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

With no annotations, the description carries the full burden. It discloses the key behavioral trait: cancellation is only possible for scheduled/queued runs that have not completed. This adds value beyond the schema. Minor omission: it doesn't state whether cancellation is irreversible or any side effects.

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?

The description is a single, concise sentence with no wasted words. It directly conveys the core purpose and condition, making it easy for an AI agent to parse quickly.

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 simple cancellation tool with two required parameters and no output schema, the description covers the essential functionality and eligibility condition. It could be slightly improved by mentioning the outcome (e.g., success status) but is largely complete.

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 coverage is 100% with descriptions for both parameters. The description implicitly adds semantics by specifying that run_id must refer to a scheduled/queued run, which is not captured in the schema. This extra context justifies a score above baseline.

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 clearly states the action (cancel), the resource (scheduled/queued durable function run), and a condition (not completed yet). It distinguishes the tool from siblings like create_function_run or invoke_function.

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 provides clear context on when to use (for scheduled/queued runs not yet completed) but does not explicitly mention when not to use or list alternative tools. The condition is well-stated, but additional guidance on alternatives (e.g., redrive_function_run) would improve it.

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