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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the description only needs to add context beyond those. It does so by stating that the tool returns lead count, list type (set or query), and source for each list. It does not mention pagination or a full return schema, but that is a minor gap for a simple read-only enumeration.

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 three sentences with the main function front-loaded, followed by return details and related-tool guidance. Every sentence earns its place, and there is no filler or repetition.

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 one-parameter read-only tool whose annotations already cover the safety profile, the description is complete: it states what is listed, what fields are returned, and how to obtain both campaignId and leadListId. The absence of pagination details is acceptable given the simple scope.

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 schema has one required campaignId parameter with 0% description coverage, so the description must compensate. It only indirectly defines the parameter by saying 'in a campaign' and by directing users to campaignstack_list_campaigns to find valid campaign IDs. This is helpful but lacks explicit format, examples, or a direct statement of what campaignId represents.

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 opens with 'List all lead lists in a campaign with lead count per list', clearly stating the verb, resource, and scope. It also specifies the returned attributes (type and source), and distinguishes this from related tools by anchoring it to a campaign and pointing to campaignstack_list_campaigns for IDs.

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 gives explicit chaining guidance: 'Use the returned leadListId values with campaignstack_get_lead_list or campaignstack_add_leads_to_list' and 'Use campaignstack_list_campaigns to find valid campaign IDs.' It does not explicitly contrast this tool with siblings like campaignstack_list_external_lead_lists, but the campaign scoping and next-step routing provide clear usage context.

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