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

Annotations already mark the tool as destructiveHint=true and readOnlyHint=false, so the mutation semantics are covered. The description adds useful behavior beyond that: it explicitly lists non-changeable fields, documents the success and failure return shape, and clarifies that only requested fields should be included. This is strong supplementary context.

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-structured with clear sections for required, optional, non-changeable, and return values. Every sentence adds practical guidance, and the most important instruction ('Update an existing person') is front-loaded. It is detailed without being bloated.

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 simple update tool, the description covers required parameters, optional usage guidance, unsupported fields, and return behavior. The schema provides rich detail for workspace_id and idempotency_key, so their absence from the description does not leave a meaningful gap. The tool is fully callable based on the provided metadata.

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 100%, so the baseline is 3. The description adds value by clarifying that first_name, last_name, and job_title should only be included when the user wants them changed, and by emphasizing that person_id is required. It does not repeat the detailed workspace_id/idempotency_key semantics, but those are already well documented in the schema, so this is not a significant gap.

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 begins with 'Update an existing person (contact) in the current workspace', which uses a specific verb and resource, and the word 'existing' distinguishes it from creation tools like well_create_person. The added 'change, fix, rename, or edit' phrasing reinforces the intended use case and separates it from deletion and creation siblings.

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 explicitly states 'Use this tool when the user asks to change, fix, rename, or edit a person's fields', giving clear selection criteria. It also lists what cannot be changed and notes that dedicated tools are 'not yet available', preventing the agent from attempting this tool for unsupported field updates.

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