get_registration

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

With no annotations present, the description carries the full burden and handles it well by disclosing default-date behavior, all-meal behavior when meal is omitted, and the api_key fallback to MESS_API_KEY. It does not go into error cases or edge behavior, but it adds meaningful behavioral detail beyond the schema.

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 compact, front-loaded with the core purpose, and uses a clear Args section for parameters. Every sentence adds value, with no repetition of schema defaults or filler content.

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 read-style lookup tool with an output schema present, the description covers invocation semantics, parameter behavior, and default values sufficiently. It does not need to explain return values because the output schema exists, and no required inputs or complex edge cases are missing.

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 fully compensates by documenting each parameter: valid meal values ('breakfast', 'lunch', 'snacks', 'dinner'), date format (YYYY-MM-DD), optionality, and api_key fallback to an environment variable. This is exactly the kind of semantic enrichment the schema lacks.

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 states a specific action ('Look up') and a precise resource ('the registration for a single meal'), and further clarifies scope by describing behavior when meal or date is omitted. This makes the tool's purpose immediately understandable and distinct enough from siblings like get_monthly_registration or check_registrations.

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 clearly explains the optionality semantics: omitting meal returns all meals for the date, and omitting date defaults to today. It does not explicitly name alternative tools or exclusion conditions, so it stops short of a 5, but the usage context is clear.

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