Update a customer

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

Annotations already declare the operation as non-readOnly, non-destructive and idempotent, so the safety profile is covered. The description adds genuine behavioral context beyond that: omitted fields are preserved unchanged, clarifying the merge/patch semantics. It does not describe error or permission behavior, so it falls short of a 5.

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?

A single efficient sentence that front-loads the verb and resource before the partial-update qualifier. Every clause earns its place with no waste.

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 presence of an output schema means return values need not be explained, and the annotations cover the safety profile. But with 9 parameters at 11% schema coverage and a nested address object, the near-total absence of parameter semantics leaves a meaningful gap for a mutation tool.

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 only 11%, so the description carries most of the burden for parameter meaning, and it names no fields at all. The generic phrase 'given fields' adds nothing about id, email, phone, the nested address object, or their formats. The low-coverage gap is not compensated.

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: 'Changes ... a customer'. An agent can distinguish it from create_customer and find_customers by the modification verb, though no sibling is named explicitly. Clear but without explicit sibling differentiation.

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?

Usage is implied by the verb (modify an existing customer), and the partial-update note signals this is a field-level edit rather than a full replacement. However, there is no explicit guidance on when to use this versus create_customer or find_customers, and no prerequisites or exclusions.

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