get_custom_items

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

With no annotations, the description carries the full burden and does an exceptional job: it declares the operation is read-only, that scripts are never executed, that empty lists are valid while wrappers/malformed members are errors, and that units/origin are unverified metadata. It also explains compact vs full output structure and derived metadata placement.

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 dense but every sentence adds behavioral or routing information, and the first sentence is a clear front-loaded definition. It could be slightly better structured with parameter guidance, but it is not padded.

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/list tool with an output schema, the description covers content semantics, error behavior, and the full-read continuation well. The main gap is the undocumented optional parameters, but that is already captured in parameter_semantics; overall the agent gets enough context to call the tool safely.

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% and the description does not compensate. Only 'detail' is indirectly referenced via detail='full', while api_key and athlete_id are never explained; without enums or schema docs the agent cannot infer valid values or their roles.

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 'Read custom-item definitions without executing their content', stating a specific action and resource and adding a key safety qualifier. It also distinguishes itself from get_custom_item_by_id by framing the sibling as the continuation for full per-item reads.

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?

It explicitly directs agents to get_custom_item_by_id(..., detail='full') when full field preservation is needed, giving a concrete alternative condition. It does not enumerate exclusions for other siblings, but the 'read without executing' framing and compact-output behavior imply when this list tool is appropriate.

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