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

Annotations already declare readOnlyHint=true, and the description adds context about the shared address book and date-window filtering. However, it does not disclose pagination behavior, default ordering, or any limits beyond what the schema properties already indicate.

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 concise sentences with key information front-loaded. The second sentence mentioning the REST endpoint is extra but not verbose; it could be considered unnecessary for an AI agent.

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?

Combined with the full parameter schema and readOnly annotation, the description covers the resource scope and optional filters. Missing mention of return shape, but for a straightforward list tool this is acceptable.

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 100% with all parameters described, so the description adds little beyond the schema. It references 'creation-date window and order' which maps to from/to and order parameters, but provides no new syntax or format details.

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 uses a specific verb ('List') and resource ('contacts in the shared address book'), clearly distinguishing from siblings like get_contact (single retrieval), create_contact, and update_contact. Mentioning optional creation-date window and order further clarifies the tool's 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 implies use for listing contacts with optional date filtering and ordering, but does not explicitly state when to prefer this over aircall_search_contacts or other alternatives. No exclusions or alternative tool references are provided.

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