list_registered_extras

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

No annotations are present, so the description carries full responsibility. It adds behavioral details such as date defaulting to today and API key env fallback, and the verb 'List' implies a read-only operation. However, it does not explicitly state that no changes are made, nor cover error or empty-result behavior.

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?

Two-line purpose followed by a compact Args list with no filler. All sentences earn their place and the most important information is front-loaded.

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 list operation with an output schema present, it covers all parameters, defaults, and auth. The main gap is not naming sibling tools or likely edge cases such as invalid meal_type/date or empty results, so it is strong but not fully comprehensive.

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 00, and the description fully compensates: meal_type gets explicit allowed values, date gets format and default behavior, and api_key gets the env fallback. This adds meaning far beyond the bare string/null schema.

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 opening sentence uses a specific verb ('List') and resource ('extra items the user has already booked for a meal'), which clearly identifies the operation and distinguishes it from sibling tools like list_available_extras or list_extras_in_range.

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 conveys the context (already-booked extras for a meal/date), which implies the use case, but it never names alternatives or explicitly states when not to use it. Sibling differentiation is left to the reader.

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