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

Annotations already declare readOnly, idempotent and closed-world, so the safety profile is covered. The description adds genuinely non-structured context: it is a public, unauthenticated endpoint ('no key needed') and the intended position in a multi-step flow. It doesn't discuss caching or list stability, which is a minor omission.

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 short sentences with zero filler; the workflow role and the no-key precondition are front-loaded before the chaining instruction. Nothing repeats the name or title verbatim without adding information.

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 parameterless lookup with no output schema, the description covers purpose, auth requirement, what is returned (languages with IDs) and the next step. The only gap is the shape of the response array beyond 'IDs', which is acceptable for a simple enumeration tool.

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?

Zero parameters, so the baseline is 4. The description does useful work by explaining how the returned language IDs are consumed downstream, which is the only 'parameter-like' semantics that matters here.

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?

Specific verb (List) plus specific resource (languages Tolk2Go interprets) and what is returned (with their IDs). It is clearly distinguishable from siblings like list_language_pairs, list_qualifications and list_situations, which enumerate different resource types.

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?

Explicitly positions the call as 'Step 1 of booking' and names the follow-up tool tolk2go_interpreting_list_language_pairs with the exact argument to pass. It also states the precondition 'no key needed'. It does not say when this tool should be skipped, but the workflow context is unambiguous.

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