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

Annotations already declare readOnlyHint=true, and the description adds value by detailing cursor-pagination, return structure, and available filters. There is no contradiction; the behavior is fully disclosed.

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 about four sentences, front-loaded with action and pagination, followed by return structure, filters, and sibling guidance. It is efficient but could be slightly more concise by omitting the full field list (though no output schema exists).

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 list tool with 6 parameters, no output schema, and no nested objects, the description provides complete context: purpose, pagination method, return format, filters, and relationship to siblings. No gaps remain.

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 0%, so the description carries the burden. It lists four filters (campaign, interestStatus, suppressed, replied) that map to four of the six parameters. The remaining two (limit, cursor) are pagination parameters implied by 'cursor-paginated', but not explicitly described. This is sufficient but not perfect.

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 action (list/export leads) and the resource (leads with contact-level disposition). It distinguishes from siblings by mentioning update_lead and suppress_lead as alternatives for write operations, and explicitly notes this is the export surface without a separate CSV endpoint.

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 explicit guidance on when to use this tool (for listing/exporting leads) and when to use alternatives (update_lead for writing disposition, suppress_lead for opting out). It also implies when to paginate to dump the full book.

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