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

Beyond the annotations (openWorldHint, non-idempotent, non-destructive), the description discloses credit costs, the asynchronous background-job nature, duplicate/blocklist/email filtering before credits are spent, and response fields like creditsPerProspect and estimatedCredits. No contradiction with annotations exists.

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 dense but purposeful, opening with 'SPENDS CREDITS' and then covering the core function, cost, filtering, async behavior, and usage guidance. It is longer than minimal but every sentence contributes important context; slightly tighter organization would earn a 5.

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?

Given three parameters, a credit-costing side effect, and no output schema, the description covers required inputs, defaults, maximums, cost reporting, async completion via list_leads, and preflight checks. It does not detail error handling or full response shape, but provides enough for an agent to invoke it correctly.

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?

Input schema coverage is 100%, so the schema already documents campaignId, icpId, and count, including defaults and maximums. The description restates these defaults and adds related workflow hints (list_icps, list_campaigns, cost implications), but it does not add substantially deeper parameter meaning beyond the schema.

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 tool sources prospects from Emailchaser's contact database using an ICP's targeting criteria and adds them to a campaign as leads. The verb 'source' plus the campaign resource is specific, but it does not explicitly name or differentiate from sibling tools like add_leads, which would push it to a 5.

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 clear context for use: check get_credit_balance and get_audience_size first, poll list_leads for async results, and on subsequent calls page deeper into the audience rather than re-revealing the same people. It does not explicitly state when to choose add_leads or another alternative, so it stops short of full exclusions.

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