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

Beyond the readOnlyHint and openWorldHint annotations, the description adds substantial behavioral context: fixed lead fields, empty values represented as null, the distinction between state and status, the maximum limit of 500, and the workspace permission requirement 'Lead-Daten freigeben'. This is meaningful operational detail that helps an agent invoke the tool correctly.

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 front-loaded with the core purpose and then provides dense, relevant detail. It is somewhat long, but the length is justified by the need to compensate for 0% schema description coverage and to explain state versus status.

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 the 0% schema coverage, the description does most of the necessary work: it explains the lead fields, state/status semantics, filtering syntax, limit cap, workspace behavior, and permission requirements. The only notable gap is that campaign_id is not explicitly described beyond the campaign-scoped context.

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 for all four parameters. It thoroughly explains state filtering (including accepted values, comma-separated syntax, and examples), limit max 500, and workspace slug behavior, but only implicitly covers campaign_id rather than stating explicitly that it identifies the campaign.

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 states a specific verb and resource: listing leads of a lemlist campaign, including the fixed lead fields and status semantics. It is clear what the tool does, though it does not explicitly differentiate this tool from siblings such as lemlist_search_people or lemlist_add_leads.

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?

Usage is implied by the campaign-scoped description and the optional state filter, which suggests this is for retrieving campaign leads. However, there is no explicit guidance on when to use this tool versus related tools like lemlist_search_people or lemlist_list_replies.

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