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

Beyond readOnlyHint=true, the description discloses substantive semantics: 'displaying=false即不在架,OPEN不代表展示' warns that OPEN status does not imply visibility, '无名额/报酬保证' preempts false assumptions about quotas/rewards, and '不存在found=false' tells the agent how absence is signaled. These are exactly the behavioral facts annotations cannot convey.

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?

Every clause carries information and nothing is padded, but the telegraphic semicolon-separated phrasing is choppy and leads with return payload rather than purpose. Dense and useful, if slightly hard to parse.

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 burden well: body, author supply, isMine under auth, displaying state, and the found=false absence case. Error handling beyond 'not found' is unaddressed, but for a one-parameter read tool this is nearly complete.

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?

There is a single required parameter already fully documented in the schema ('需求 id(cuid)', 100% coverage). The description only echoes it via 'opcmenu://need/{id}', adding no new constraint or format guidance, so the baseline 3 for high schema coverage applies.

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 identifies the resource and its payload ('公开需求正文、作者供给;登录含isMine'), and the surrounding workflow chain distinguishes it from search_needs and list_needs_feed. The verb itself is only implied, but combined with the title an agent can immediately tell this is a fetch-by-id for a single need.

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 chain 'search_needs→get_need→contact_need→send_message' explicitly places this tool between discovery and outreach, naming the sibling that precedes and follows it. It does not state an exclusion case (e.g., when to use get_need_recommendations instead), which keeps it below a 5.

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