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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds the crm-schema prerequisite but does not explain the consequence of destructiveness — e.g. whether omitted fields are cleared or preserved — which is the key behavioral question for this tool.

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?

Two short sentences, purpose front-loaded before the prerequisite hint, with no filler. It is lean to the point of under-informing, but nothing is wasted.

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?

An output schema exists so return values needn't be explained, but for a destructive mutation with a nested custom_fields object, the description should clarify partial-update semantics and the failure mode for invalid field codes. Only the field-code prerequisite is covered.

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% and the description adds nothing about parameters beyond repeating the crm-schema requirement already stated in the custom_fields schema text. Baseline 3 is appropriate since the schema carries the load.

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?

States a specific verb and resource ('Update an existing person (contact) in the CRM'), which cleanly distinguishes it from the create/delete/get person siblings by name and action. It doesn't explicitly call out the sibling boundary, but the resource+verb combination is unambiguous.

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 only guidance is a prerequisite for custom fields ('Use the crm-schema resource to discover available custom fields'). There is no statement of when to choose this over create-people-tool or how it relates to partial updates, so usage is only implied.

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