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

The readOnlyHint annotation already indicates this is a safe read operation. The description adds the search-oriented behavior and the REST endpoint, but does not disclose details like return format, pagination behavior, or potential edge cases. Given the annotation coverage, the description provides adequate but not rich additional transparency.

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, efficient sentence that front-loads the purpose and includes the REST endpoint for additional reference. There is zero redundancy or unnecessary commentary.

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 read-only search tool with three optional parameters, no output schema, and a clear purpose, the description is mostly complete. It could explicitly mention that the tool returns a list of calls or describe pagination behavior, but the schema covers pagination parameters and the readOnlyHint covers safety. Overall it is adequate without being exhaustive.

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 already describes all three parameters (q, page, per_page) with full coverage. The description goes beyond the schema by giving concrete examples of valid search terms (phone number, tag, direction) for the q parameter, which helps the agent understand what can be searched. This extra context justifies a 4 instead of the baseline 3.

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 calls by a free-text term'. It identifies the resource (calls) and the mechanism (free-text), which distinguishes it from simple list/get operations. However, it does not explicitly name sibling alternatives like aircall_list_calls or aircall_get_call, so it falls just short of a 5.

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: whenever you need to find calls based on a free-text term such as phone number, tag, or direction. It does not include explicit when-not-to-use guidance or references to alternative tools, but the intended usage is unambiguous.

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