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

The annotation 'readOnlyHint: true' already indicates a safe read operation, so the bar is lower. The description adds context that the search is via the REST endpoint 'GET /contacts/search' and that the search term matches against name, phone, or email, but it does not disclose additional behavioral aspects such as pagination behavior, result ordering, or response structure. It adds some value but not substantial behavioral details.

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 a single, well-structured sentence that immediately states the action and scope. It includes the REST endpoint as supplementary context without redundancy. Every word earns its place, and it is front-loaded with the core purpose.

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?

The tool is relatively simple with three optional parameters, full schema documentation, and a read-only annotation. However, there is no output schema, and the description does not explain what the search returns (e.g., a list of contact objects, pagination details). While the core functionality is clear, the lack of return-value information leaves a modest gap in 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 input schema has 100% coverage for all three parameters, each with a description, so the baseline is 3. The description enriches the 'q' parameter by providing concrete examples (name, phone number, email), but it does not add any information about 'page' or 'per_page' beyond what the schema already provides. The added value is minimal.

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 function: 'Search contacts by a free-text term (e.g. name, phone number, email).' This is a specific verb ('search') plus resource ('contacts') and scope ('free-text term'), which distinguishes it from sibling tools like 'aircall_list_contacts' (list all) and 'aircall_get_contact' (get by ID). The purpose is unambiguous and well-defined.

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 does not provide explicit guidance on when to use this tool versus alternatives. It implies usage when a free-text search term is available, but it never mentions exclusions or alternative tools such as 'aircall_list_contacts' for unfiltered listing or 'aircall_get_contact' for direct retrieval. There is no comparison or when-not-to-use advice.

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