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

The readOnlyHint annotation already establishes this as a safe read. The description corroborates with the API verb (GET /api/v3/contacts), which adds modest confirmation of the read-only nature. It does not disclose pagination behavior, result limits, or what happens with no filters, so it adds little beyond the annotations.

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?

Two short sentences with the core purpose front-loaded and the API mapping appended compactly. No filler or redundancy.

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 list tool with fully documented parameters and no output schema, the description covers the essential purpose and filter scope adequately. Only minor gaps remain, such as whether unpaginated calls return everything or whether filtering is server-side.

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 email, phone, page, and items_in_page are all documented in the schema. The description's mention of whole/partial email and phone matching restates that schema text rather than adding new semantics, so the baseline 3 applies.

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?

States a specific verb (list) and resource (end-user contacts), and the email/phone search qualifier narrows the scope further. It is clearly distinct from the sibling atera_create_contact, though it does not explicitly differentiate itself from other list tools such as atera_list_customers.

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?

"Optionally searching by whole or partial email or phone number" implies when the filter parameters are useful, which is decent contextual guidance. However, there is no explicit when-to-use vs. alternative framing and no exclusions or prerequisites.

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