add_activity

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It adds useful context about the day range ('must be between 1 and the trip's length') and the purpose of the details field, but it does not mention error handling, side effects, idempotency, or what the response contains. This is partial transparency, not comprehensive.

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 two sentences, front-loaded with the action and target, followed by essential parameter guidance. Every sentence adds value without redundancy, making it 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 simple add operation with four parameters and an existing output schema, the description covers the core purpose, the key day validation rule, and the details field's intended use. It doesn't address potential errors or return behavior, but these are partially covered by the output schema and the simplicity of the tool. Overall, it is sufficient but not exhaustive.

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%, so the description must compensate. It meaningfully explains the 'day' parameter (range constraint) and 'details' (content guidance), adding value beyond the plain schema titles. The other parameters (trip_id, title) are self-explanatory and not explicitly described, but the description still covers the non-obvious ones.

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 verb and resource: 'Add one activity to a specific day of the trip.' This is specific and distinguishes the tool from siblings get_itinerary (retrieval) and remove_activity (deletion), which serve different purposes.

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 implies usage by stating the action and location ('to a specific day of the trip') and provides constraints on the day parameter. However, it does not explicitly name alternatives or state when not to use this tool, leaving differentiation to inference from the verb and sibling names.

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