Update customer

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

Beyond the annotations (readOnlyHint=false, destructiveHint=true, idempotentHint=false), it explains that fields supplied are overwritten while omitted fields stay unchanged, that a successful write increments the SyncToken, and that stale tokens fail with error 5010. This gives materially useful operational detail that the annotations alone do not convey; no contradiction.

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?

Every sentence earns its place: purpose, use cases, write semantics, non-idempotence, and the token precondition are all stated with minimal redundancy. The most decision-relevant information is front-loaded in the first two sentences.

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?

Given the 3-parameter shape, a nested customer payload, an output schema, and rich annotations, nothing an agent needs to invoke the tool correctly is missing: it knows the update semantics, the required prerequisite token, the error mode, and the resource. Return values are already covered by the output schema.

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% and the schema already documents customer_id, sync_token, and the customer object, so the baseline is a 3. The description adds value by defining the payload as a sparse patch ('leaves omitted fields unchanged') and reinforcing that the sync_token must come from a fresh get_customer, which clarifies how to use the required parameters beyond their individual field docs.

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?

Description opens with a direct verb+object ('Update an existing customer') and names exact use cases ('correct contact details, addresses, or the display name'). It further distinguishes itself as a sparse update rather than a replacement, which differentiates it from create/delete and from a hypothetical full overwrite.

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?

It explicitly frames when to use the tool ('Use it to correct...') and requires 'Id plus the SyncToken from a fresh get_customer', effectively pairing it with a read step. It stops short of naming explicit exclusions such as 'use create_customer for new records' or 'use delete_customer for removal', though 'existing customer' and sparse-update wording make those boundaries clear.

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