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

With no annotations supplied, the description carries the full burden and does reasonably well: it discloses that calls go through the caller's OpenAny gateway credentials and that charges and authorization are gateway-determined, which is material cost/auth context an agent cannot get from the schema. It still does not state error behavior for missing identifiers or whether the lookup is strictly read-only, but the essentials are covered.

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?

Front-loads purpose, then constraints, then versioning, then return contents and gateway billing. Every sentence carries information; the only mild redundancy is the separate sentence about credentials and charges, which could be folded in, but it is short and relevant.

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 3-parameter lookup with no output schema, the description covers purpose, preconditions, version selection, returned field groups, and billing/auth source. The only gap is that it does not explain what happens when both id and fgmc are supplied or when the identifier resolves to nothing.

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 coverage is 100%, so the baseline is 3, but the description adds cross-parameter meaning beyond the schema: the at-least-one-of id/fgmc requirement (the schema itself marks nothing required) and the version-selection semantics of refer_date including the default to the currently effective version. That is genuine added value, not restatement.

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?

States a specific verb and resource ("Retrieves regulation details") and enumerates the returned data, so it is clearly a single-record lookup. It does not explicitly name the sibling search tools (yuandian_post_open_rh_fg_search / fg_zq_search) as the way to obtain an id or fgmc, so differentiation is implied rather than stated.

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?

Gives real invocation preconditions (body must not be empty, at least one of id or fgmc) and explains when refer_date should be used versus omitted. However, it never says when to prefer this over the search siblings, nor that search must run first to obtain an identifier, leaving the routing decision to inference.

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