Extend trial

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

The annotations are sparse (all false), so the description carries the burden of explaining behavior. It adds crucial information: the tool is dry-run by default and only actually changes data when confirm:true is passed. It also discloses the status restriction. This adds value beyond the annotations and does not contradict them.

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 exactly two sentences, front-loaded with the core action. The second sentence packs the critical constraints and safety behavior. There is no filler or redundancy, making it highly concise and well-structured.

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 tool with 3 parameters, no output schema, and only basic annotations, the description covers the essential aspects: purpose, precondition, and dry-run default. A minor gap is not describing what happens if the status is not trial, but 'only works for' is sufficient. Overall, it is complete enough 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?

Every parameter in the schema has a thorough description, including the confirm safety gate. The tool description does not add additional parameter semantics beyond what the schema already provides. With 100% schema coverage, a baseline of 3 is appropriate.

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 opens with a specific verb and resource: 'Extend a trial customer's trial end date by a number of days.' It adds a clear constraint ('Only works for customers whose status is 'trial'') that differentiates it from sibling tools like get_customer or update_ticket_status. This is a strong, unambiguous purpose statement.

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 usage context: it only applies to trial-status customers, and it implies a safe workflow by explaining the dry-run default. It does not explicitly name alternatives or exclusions, but the precondition and safety gate offer sufficient guidance. A score of 4 reflects clear context without explicit sibling comparisons.

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