yan_usage_guide

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds that the payload is guidance text aimed at clients lacking resources/prompts support, which is useful context, but says nothing about the size, language, or structure of the returned guide.

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?

A single sentence that front-loads the verb and enumerates the covered topics, then closes with the client-condition. No padding, though the long topic list is dense and could be trimmed without losing meaning.

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 zero-parameter, read-only guidance tool with no output schema, the description conveys what the guide covers and who it is for, which is enough to invoke it correctly. It could go one step further by noting that the response is prose documentation so an agent knows to read rather than parse structured data.

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 takes zero parameters, so there is no parameter semantics to explain and the baseline is 4. Nothing in the description misrepresents the empty input schema or implies hidden arguments.

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: it returns a guide covering tool selection, person extraction, multi-group monitoring, summarization workflow, and source citation. That is far more informative than a tautology, but it never names or contrasts with the closest sibling (wechat_reader_capabilities), so sibling differentiation is left to inference.

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?

Provides an explicit audience/trigger: AI clients that do not support MCP resources/prompts, implying the alternative (native resources/prompts) should be used when available. It stops short of saying when this is unnecessary in an MCP-capable client or how it relates to wechat_reader_capabilities.

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