list_leads

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

With no annotations provided, the description carries the full behavioral burden. It does well by disclosing that leads are deduplicated across channels, that account_id auto-resolves when omitted, that per_page is capped at 250, and by describing the exact response shape and lead fields. It does not mention auth requirements or ordering, but for a read/list operation the disclosed behavior is substantial.

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 well organized with an intro, a clarifying concept sentence, an Args block, and a Returns block. Each section earns its place, and the key defining trait (deduplicated person record) is front-loaded. No filler or redundant restatement of the tool name.

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 list tool with four optional parameters and no annotations, the description is remarkably complete: it defines the resource, explains the deduplication behavior, documents every parameter, specifies pagination constraints, and lists the return fields. There is no obvious missing information an agent would need 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?

Schema description coverage is 0%, so the description must compensate for the bare schema. It does: account_id 'auto-resolves if omitted,' company_id 'filter to one company,' per_page 'page size (max 250),' and page '1-indexed.' This adds real semantic value beyond the parameter names and defaults.

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 a specific verb and resource: 'List leads (unique people) across calls, forms, and texts.' It then defines a lead as CallRail's deduplicated person record, which clearly distinguishes this tool from raw call, form, and text listers among the siblings. The mention of get_lead_timeline for cross-channel history further sharpens the tool's identity.

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 explains what list_leads returns and explicitly points to get_lead_timeline when a lead's full history is needed, providing a clear alternative. It does not exhaustively enumerate when not to use the tool versus list_calls, list_form_submissions, or list_text_messages, but the deduplication framing makes the intended use case evident.

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