register_meal

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

With no annotations, the description carries the behavioral burden. It discloses that existing registrations are updated, that guests are billed additionally, and that api_key falls back to an environment variable. These are meaningful behavioral details beyond a simple create/update statement.

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 purpose and key behavioral nuance are front-loaded, followed by a clean Args block. Every line adds information, and there is no filler or repetition of schema fields. The length is appropriate for the five parameters.

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?

The description, combined with the input and output schemas, gives an agent everything needed to invoke the tool correctly: required fields, parameter constraints, prerequisite check, and update semantics. The mention of check_registrations also covers a key workflow dependency.

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 fully explain parameters. It does: date format is specified, meal_type values are listed, meal_mess includes concrete examples, guests has a range and billing note, and api_key has fallback behavior. This is comprehensive parameter documentation.

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 'Create or update a meal registration,' which names a specific verb and resource. The explicit upsert behavior distinguishes it from related tools like cancel_meal and get_registration, so an agent can immediately understand what this tool does.

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 gives clear guidance to use check_registrations first to confirm the registration or cancellation window is open. It does not explicitly contrast with monthly registration tools or other alternatives, but the precondition is stated directly and usefully.

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