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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the description needn't repeat safety. It adds the behavioral trait that the tool returns 'exact account and filtered lead totals,' which is not in the annotations or schema, providing additional context about the output.

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 a single sentence, front-loaded with the core purpose ('List leads using common filters') and immediately adds the distinctive return value ('exact account and filtered lead totals'). No wasted words.

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 tool's complexity (6 optional filter parameters, 1 enum), the schema covers all parameters, annotations cover safety, and an output schema exists (not shown but mentioned). The description clearly states what it does and what it returns, so nothing critical is missing.

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 schema has 100% description coverage for all 6 parameters, so the description does not need to add parameter details. However, the description's mention of 'using common filters' implies the filtering parameters, but adds no extra meaning beyond the schema. Baseline 3 is appropriate.

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's purpose: 'List leads using common filters and return exact account and filtered lead totals.' It identifies the resource (leads) and the action (list), and distinguishes it from siblings by emphasizing the 'exact account and filtered lead totals' return, which is unique among list tools.

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 implies when to use this tool (when you need to list leads with filters and get totals) but does not explicitly exclude alternatives like get_lead or list_funnels. However, given the sibling list, the distinction is clear enough for an agent to infer the right context.

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