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

Annotations already assert read-only, idempotent, and non-destructive behavior, so the bar is lower. The description adds that the returned document is 'complete' and 'canonical', which suggests authoritative full-content delivery, but it does not describe behavior for missing ids, invalid ids, or how canonical is determined.

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?

One short, front-loaded sentence that conveys the entire operation without unnecessary detail. Every word contributes meaning, and no filler is present.

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 single-parameter, read-only, idempotent lookup with an output schema and fully documented input, the description covers the essential invocation contract. Return values do not need to be repeated in the description because an output schema exists, and the remaining terms like 'NFH' and 'canonical' are domain-specific rather than operationally critical.

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?

The schema fully documents the only parameter, id, including its type and that it is returned by search. The description only restates that access is by id, so it adds little beyond the schema. The baseline 3 is appropriate 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?

The description uses a specific verb ('Return') with a precise resource scope ('one complete canonical NFH document') and the lookup key ('by id'). This clearly differentiates it from search and list siblings, which operate over sets of documents rather than a single canonical document.

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 implies that this tool is used when the caller already has a document id and wants the full canonical document, and the schema reinforces that the id comes from search. However, it does not explicitly name alternatives or state when not to use this tool.

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