search_user

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

Annotations already declare readOnlyHint=true and destructiveHint=false, indicating a safe read operation. The description adds useful context about search constraints (e.g., name searches only return contacts) and clarifies that at least one parameter is required ('you must provide...'), which isn't in the schema. However, it lacks details on response format, pagination, or error handling, leaving behavioral gaps.

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 appropriately sized with two sentences that are front-loaded with key information (search purpose and required parameters). However, the second sentence could be more concise, and there's minor redundancy (e.g., repeating search criteria). Overall, it's efficient with little waste.

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 the tool's moderate complexity (search with constraints), 100% schema coverage, and annotations covering safety, the description is adequate but incomplete. It lacks output details (no schema provided), doesn't explain how multiple parameters interact, and omits error cases (e.g., no matches). For a search tool, this leaves gaps in contextual understanding.

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 description coverage is 100%, so the schema fully documents parameters (email, phone, name). The description adds minimal semantics by reiterating the searchable fields and noting the contacts limitation for name searches, but doesn't provide additional syntax, format, or usage details beyond what's in the schema. Baseline 3 is appropriate as the schema does the heavy lifting.

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 with specific verbs ('Search for a User') and resources ('phone number, email address, id or name'), distinguishing it from sibling tools like 'get_user' (which likely retrieves a single user by ID) and 'search_users' (which may have broader search capabilities). It precisely defines what the tool does and its scope.

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 provides clear context for when to use this tool by specifying search criteria (phone, email, id, or name) and noting that name searches are limited to contacts. However, it does not explicitly state when not to use it or name alternatives (e.g., 'get_user' for ID-based retrieval or 'search_users' for broader searches), leaving some ambiguity compared to sibling tools.

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