lookup_user_id

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

With no annotations, the description carries the full burden. It discloses key behavioral traits: exact match first, fall back to fuzzy matching if no exact match, and returns all matching users with the same name. This goes beyond the basic 'lookup' verb. However, it does not mention error handling (e.g., no match found at all) or output format, though the output schema may cover that.

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 description is two short sentences, front-loaded with the main purpose. Every sentence provides value: the first states what it does, the second explains the matching behavior. No wasted words.

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 simple lookup tool with one parameter and an output schema, the description covers the essential context: purpose, matching rules, and multi-result behavior. It does not explicitly state what happens when no fuzzy match is found, but the output schema likely defines the return structure. This is a minor gap for an otherwise simple tool.

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 0%, so the description must compensate. The description explains the 'name' parameter as '成员姓名' (member name) and adds matching semantics: exact match, fuzzy fallback, and multi-result return. This adds significant meaning beyond the bare schema property definition.

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 clearly states the tool's purpose: '通过成员姓名查找 UserID' (find UserID by member name). This is a specific verb+resource combination. It also distinguishes from siblings by explaining it's for specifying the recipient when sending messages, which differentiates it from list_users_by_department.

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 implies usage context: '用于发送消息时指定接收人' (used to specify recipient when sending messages). This informs the agent when to use this tool (before sending messages) but does not explicitly mention alternatives or exclusion conditions. Sibling tool names like send_text_message suggest this is a prerequisite step, but the guidance is implied rather than explicit.

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