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

Beyond the annotations, the description adds meaningful behavior: authorization scope, no repeat charge, cursor continuation semantics, workspace/suppression/retention constraints, and test-key behavior. These details are useful, though some constraints such as suppression and retention are stated only in general terms.

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 compact and front-loads the core purpose before covering access, billing, pagination, and test behavior. It is mostly efficient, though the test-key sentence is niche and the cursor wording could be tighter.

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 paginated list tool with no output schema, the description covers auth, billing, pagination, and policy constraints reasonably well. However, the missing explanation of the query parameter and the cursor/next_cursor naming mismatch leave gaps an agent must resolve elsewhere.

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 0%, so the description must explain both parameters, but it only addresses continuation and calls the value 'next_cursor' while the input schema names the parameter 'cursor'. The 'query' parameter is not explained at all, leaving invocation semantics incomplete despite the small parameter count.

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 states a specific verb and resource: read up to 100 saved verified contacts in the authorized workspace. It clearly positions the tool around saved leads, but it does not explicitly name sibling tools such as fairvalid_search_leads or fairvalid_get_results to sharpen differentiation.

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?

It gives useful operating context, including the required leads:read scope and the fact that reads incur no repeat charge. Pagination guidance is present, but there is no explicit statement of when to use this tool instead of alternatives like search_leads or get_results.

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