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

Annotations already indicate a mutating, non-idempotent, non-destructive operation. The description adds a specific behavioral trait: an invalid status value triggers a response containing the valid list. This is useful context not present in annotations and does not contradict them.

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 two sentences with no filler. The first sentence states the purpose, and the second adds a valuable behavioral note, making every sentence earn its place.

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?

The description omits key operational details: it does not state whether the update is partial (only provided fields) or full replacement, nor what the success response looks like, given there is no output schema. It also doesn't mention prerequisites like an existing lead. This is insufficient for a tool with 6 parameters and no structured output information.

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 description groups parameters into 'status' and 'contact details', providing a high-level mapping to lead_status and email/phone/client_name. However, it does not explain the required identifiers (project_id, lead_id) or detail each parameter, so it only partially compensates for the low schema description coverage (17%).

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 function with the verb 'Change' and specifies the resource (lead) and scope (status or contact details). This distinguishes it from sibling tools like get_lead (read-only) and update_prompt (updates a different resource).

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 usage for modifying a lead's fields, which is clear from the verb and resource. It also provides a guideline that the lead_status must be project-defined, and that an invalid value returns the valid list, but it does not explicitly mention when not to use this tool or reference alternatives.

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