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

Annotations only declare idempotentHint/destructiveHint/openWorldHint; the description adds real behavior beyond them: a genuine change fires the LeadCategoryUpdate webhook, and re-setting the existing value is a no-op. It also discloses the important side effect that changing away from meeting_booked does NOT clear the booked-meeting mark, preventing a plausible misuse.

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?

Front-loaded with the core action, then each following sentence carries a distinct, non-redundant fact (alternate tool equivalence, non-obvious side effect, webhook/no-op behavior). No filler or restatement of the 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 mutation tool with no output schema and no destructive permission flag, the description supplies everything an agent needs: side effects (webhook), idempotency semantics beyond the hint, and cross-tool consequences for the meeting_booked value. Nothing material 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?

Schema coverage is 100%, so baseline is 3, but the description adds meaning the schema lacks: the enum value meeting_booked is documented as behaving exactly like mark_lead_meeting, which clarifies semantics of a specific allowed value. It does not further explain the id parameter, but that is already covered by the schema.

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?

Starts with a specific verb+resource ('Sets or corrects a lead's category (tag)') and immediately names the sibling tools it overlaps with (mark_lead_meeting, unmark_lead_meeting). An agent can distinguish it from update_lead, get_lead, and mark_lead_meeting without opening any 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 an explicit primary use case ('typically to fix an AI misclassification of a reply') and routes to alternatives with conditions: use mark_lead_meeting for the same effect as meeting_booked, and use unmark_lead_meeting to clear the booked-meeting mark. When-to-use and when-not-to-use are both covered.

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