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

Annotations already cover the full safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower; the description still adds genuine context: output is Markdown with source links and retrieval date, every source record is returned without merging, and the endpoint is public and paginated. This goes meaningfully beyond what the annotations declare.

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-loaded with the core purpose and generally dense, with most sentences earning their place. The final sentence partially restates the earlier English-text point, a minor redundancy rather than bloat.

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?

With no output schema, the description carries the return-value burden and does so: Markdown descriptions, source links, retrieval date, English natural-language text and pagination. Combined with the language-handling and no-merge notes, an agent has enough to call it correctly.

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 50%, with the code parameter undocumented beyond its pattern. The description compensates by reinforcing the four-digit code semantics and by clarifying the locale semantics ('English is official source text; Chinese is translated'), which adds authority nuance beyond the schema's URL-prefix explanation.

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 with scope: 'Get complete Markdown descriptions for one four-digit visa condition number.' The 'one four-digit' phrasing implicitly separates it from a search, but it never names the obvious sibling search_visa_conditions, so an agent must infer the exact-lookup vs search distinction.

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?

Adds a real usage constraint ('Do not select or merge variants') and scope exclusions ('not a personal visa record or eligibility assessment'), which steers the agent away from misuse. However, it never names an alternative tool or states the condition under which a sibling (e.g., search_visa_conditions) should be chosen instead.

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