get_custom_item_by_id

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

With no annotations, the description carries the behavioral burden and does so well: it explains the compact vs. full detail modes, what each preserves or omits, that full mode treats upstream content as untrusted data, and how an upstream '{}' maps to NOT_FOUND. This is substantive behavior beyond the name and 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 purpose is front-loaded in a single clear sentence, and the remaining sentences earn their place by explaining detail modes and error behavior. The full-mode sentence is dense but contains necessary distinctions.

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?

Given that an output schema exists, the description does not need to explain return values. It covers ID constraints, detail variants, untrusted-data semantics, and the NOT_FOUND edge case. It is slightly incomplete only in not clarifying the roles of api_key and athlete_id, but it remains sufficient for correct invocation.

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 compensate. It adds real meaning for item_id ('positive integer') and detail ('compact' vs. 'full' with behavioral differences), but api_key and athlete_id are left entirely unexplained, leaving a clear gap.

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 a specific verb and resource: 'Read one custom-item definition by positive integer ID.' It clearly distinguishes this single-item lookup from the sibling get_custom_items by emphasizing 'one' and 'ID.'

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 establishes a clear context: use this tool when you need a single custom-item definition identified by a positive integer ID. It does not explicitly name alternatives or exclusions, but the singular/ID framing is an unambiguous usage cue.

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