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

With annotations already giving idempotentHint=true and destructiveHint=false, the description adds substantial context: it MOVES contacts to 'CRM Imports' rather than deleting, preserves CRM history and campaign membership, is reversible with add_contacts_to_list, and reports already-in-default-list contacts as not_removed. This goes well beyond the annotations.

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?

Every sentence carries unique information: core purpose, move semantics, non-deletion/non-campaign exclusions, blacklist alternative, and return behavior. It is detailed yet tightly structured, with the primary action front-loaded.

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?

Despite lacking an output schema, the description covers return values, edge cases (contacts already in 'CRM Imports'), side effects, reversibility, and sibling tool routing. An agent has all necessary context to call 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?

Schema description coverage is 100%, and the schema already fully explains list_id's guard behavior and contact_ids max of 200. The tool description itself adds no parameter-specific meaning beyond that, so the baseline 3 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?

States a specific verb+resource ('Take contacts OUT of a named lead list') and clearly distinguishes itself from siblings like add_contacts_to_list, exclude_contacts_from_campaign, and blacklisting. The move-vs-delete semantics are explicit, so an agent can tell this apart without opening the schema.

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?

Gives explicit when-to-use context ('after reviewing them'), when-not-to-use ('does NOT remove it from campaigns', 'permanently drop... blacklist it instead'), and names the exact alternative tools (exclude_contacts_from_campaign, add_contacts_to_list, blacklist). Nothing is left to inference.

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