server_info

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

No annotations are provided, so the description carries the full burden. It describes the return values comprehensively (base_url, default_model, size_rules, recommended_sizes, capability_matrix, retry_policy) but does not explicitly state side effects, authentication requirements, or rate limits. It implies a read-only query, but lacks explicit safety declarations.

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?

Two concise sentences in Chinese plus a bulleted list of return fields. Every sentence adds value: the first states the purpose and usage, the second outlines the output. No fluff, front-loaded with the most important instruction.

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 no parameters and an output schema exists (true), the description is fairly complete. It lists all return fields with brief descriptions. However, it could mention error cases or what happens if the server is unreachable, but for the typical use case, it is sufficient.

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?

Input schema has no parameters (empty object), so schema coverage is 100%. With 0 parameters, baseline is 4. The description adds value by explaining what the tool returns, though it doesn't need to explain parameter semantics since there are none.

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?

Description clearly states it is a diagnostic/capability query tool, explicitly specifying it should be called before any image generation tool. The verb '诊断 / 能力查询' (diagnostics/capability query) and the resource 'routing rules and size constraint matrix' make the purpose unambiguous. It also distinguishes from sibling tools which are image generation/editing tools.

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?

Explicitly instructs to call this tool before any image generation tool ('在调任何生图 tool 之前，先调一次此 tool 拿到完整路由规则与 size 约束矩阵'). This provides a clear usage context. While it doesn't mention when not to use it, it's a one-time prerequisite, so the guidance is sufficient.

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