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

Annotations only mark the tool read-only; the description adds non-obvious behavior: fields can change until finishedAt, a failed add may still have added and charged people, and endReason/lastError values are enumerated. There is no contradiction with readOnlyHint=true.

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?

Five dense sentences, front-loaded with the return contract before caveats and alternatives. The status and error enums are inline rather than padded, and the final strategic note about search_lead_finder earns its place as usage guidance.

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?

With no output schema, the description carries the burden of explaining return semantics and does so thoroughly: statuses, completion reasons, failure reasons, credits, and the polling caveat are all specified. Minor omissions like exact skipReasons values are not needed to call the tool 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?

The single id parameter is fully documented in the schema ('importId from add_lead_finder_prospects or list_lead_finder_imports'), so the description does not need to repeat it. It adds no syntax or formatting details beyond the schema, so the baseline for full schema coverage 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?

The first sentence names the exact resource ('one Lead Finder add's progress') and lists the specific fields returned: status, added, skipped, skipReasons, email verification, and creditsSpent. This clearly distinguishes it from siblings like get_lead_finder_search and list_lead_finder_imports.

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?

Explicitly instructs the agent to poll this tool after add_lead_finder_prospects until finishedAt is set, and provides a conditional alternative: after a large add, use search_lead_finder to pick missing people. This is concrete when-to-use and when-not-to-use guidance.

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