wechat_reader_capabilities

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

The description adds context beyond the readOnlyHint=true annotation by mentioning '解析器可用性' (parser availability) and '安全边界' (security boundaries), which are behavioral facets of the extension. However, it does not explain what those boundaries are or how the returned data behaves (e.g., format, dynamic nature), so the disclosure is useful but shallow.

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 entire description is one short sentence that states the purpose without filler words. It is front-loaded with the verb and directly lists the three components of the return value, making it efficiently scannable for an agent.

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 parameterless tool with no output schema, the description must convey what the agent can learn from the result. It mentions capabilities, parser availability, and security boundaries, but lacks concrete detail about the structure or content of the response (e.g., what capabilities are listed, what parser statuses exist). Given the complexity of the sibling tools and the absence of an output schema, a bit more detail would improve completeness.

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 tool has zero parameters and the schema is fully covered (100%). With only an empty properties object, there is no parameter semantics to describe, so the base score is 4 as per the rule for parameterless tools.

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 '返回当前微信读取扩展的能力、解析器可用性和安全边界' states a clear verb ('returns') and specific resources ('capabilities', 'parser availability', 'security boundaries'), which sets it apart from siblings that list messages, contacts, or sessions. It is not perfectly concrete about what these capabilities entail, but the intended purpose is unambiguous.

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 offers no guidance on when to call this tool versus alternatives, nor does it mention any conditions or exclusions. It only states what it returns, leaving an agent to infer it is a capability-check tool. No exclusions, prerequisites, or alternative tool routing is provided.

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