file_cancel

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

Annotations state this is not readOnly, not idempotent, and not destructive, but the description adds no context beyond what the annotations already imply. It doesn't explain whether the transfer can be resumed after cancel, what happens to partial data, or whether the cancellation is immediate. For a mutation tool with zero parameter documentation and no output schema, the description should carry more behavioral burden than it does.

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?

A single sentence with no filler. It front-loads the action and resource without wasting words.

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 no-parameter mutation tool, the description is minimally adequate but leaves key operational questions unanswered: what qualifies as 'current', how to identify the transfer, and whether cancellation is reversible. These gaps matter for safe invocation, though the simplicity of the tool limits the damage.

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?

Zero parameters, so the baseline of 4 applies. The description correctly implies no user-supplied input is needed to identify the transfer to cancel.

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 (current shared file transfer), which is clear enough to distinguish from siblings like file_pause and file_resume. However, it doesn't explicitly differentiate 'cancel' from 'pause' beyond the verb choice, so it stops short of a 5.

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?

No guidance on when to use cancel versus pause or when-not to use it. The reader must infer that cancel terminates while pause suspends. No prerequisites, permissions, or alternative is named.

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