cancel_rental

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

With no annotations, the description must carry the full behavioral burden. It discloses important refund behavior: potential refunds for ver_xxx and non-refundable for ren_xxx, and instructs to check the response. This goes beyond a generic 'cancel' statement, though it does not cover other behavioral aspects like irreversibility or timing.

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 very concise: a one-sentence purpose plus two short clarifying sentences. It is front-loaded with the actionable verb and resource, and every sentence provides relevant caveats. No unnecessary words or repetition.

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 tool with one required parameter and no output schema, the description covers the core purpose, refund nuances, and advises checking the response. It does not describe the response structure or potential errors, but given the tool's simplicity, it is sufficiently complete for an agent to invoke it correctly.

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?

The schema has one parameter (rental_id) with no description. The description adds meaning by indicating the identifier format (ver_xxx vs. ren_xxx), helping the agent understand valid inputs. This compensates for the 0% schema description coverage, although it does not fully describe the parameter's purpose.

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 starts with 'Cancel a rental,' which is a specific verb and resource, clearly distinguishing it from sibling tools like get_rental, rent_number, or re_rent_rental. It further scopes the tool by mentioning refund behavior for verification rentals (ver_xxx) vs. long-term rentals (ren_xxx).

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 useful context on when cancellation is refundable (ver_xxx with no message arrived) and when it is non-refundable (ren_xxx), guiding the agent in setting expectations. It stops short of explicitly saying 'use this instead of X' or listing alternative tools, but the context is clear enough for a cancellation operation.

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