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 disclose one real behavioral trait: 'its history is kept,' signalling the record isn't purged. It omits permission requirements, whether cancellation is reversible, what happens to the recipient's state, and whether retry afterward is possible.

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 short sentence that front-loads the action and appends the important side effect. Nothing is wasted and no clause needs rereading.

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?

An output schema exists, so return values need not be described. For a mutation tool with no annotations and two undocumented parameters, the description is thin: it covers the key 'history kept' fact but not authorization, reversibility, or the meaning of its arguments.

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% for both required parameters, and the description explains neither 'message_id' nor 'recipient'. It does not clarify whether recipient identifies the sender, the destination, or the actor whose delivery is cancelled — a gap the schema leaves entirely open.

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+resource ('Cancel an unfinished delivery') and scopes it to unfinished ones, which separates it from a plain status change. However, it never differentiates itself from plausible siblings like 'release', 'retry', or 'ack', which an agent must choose between.

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 phrase 'unfinished delivery' implies a precondition (only in-flight deliveries are cancellable), giving implied usage context. It offers no explicit when-to-use, when-not-to-use, or alternative (e.g. release vs cancel) guidance, so routing between siblings is left to inference.

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