customer_update

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

No annotations exist, so the description carries the full burden, and it discloses two genuinely non-obvious behaviours: tri-state field semantics (omit vs. null) and the scoping side effect that already-issued documents are not rewritten. It omits permission/auth requirements, what happens for an unknown customer_id, and any mention of the Idempotency-Key parameter present in the schema.

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?

Three tight sentences with no filler, and the most consequential rule (omit vs. null) is front-loaded immediately after the purpose statement. Every sentence earns 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?

For an 11-parameter mutation with no annotations and no output schema, the description covers the hardest semantic problem (partial update) and the main side effect, but leaves the agent guessing about the response payload, idempotency behaviour, and error handling on a bad id.

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 0%, and the description compensates only generically by explaining that omitted fields are preserved and null clears them — a rule that applies to all nullable params but explains none of them individually. Nothing is said about tax_id vs. electronic_address, metadata merge/replace behaviour, the billing/shipping distinction, or the Idempotency-Key.

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 gives a specific verb and resource ("Change a stored customer"), which is unambiguous against customer_create and customer_get. It stops short of naming any sibling explicitly, so an agent must infer the create/read/update split from the names alone.

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 rather than stated: the patch semantics ("only the fields you send are changed") tell the agent how to call it, but there is no explicit when-to-use guidance, no alternative named (e.g. customer_create for new records), and no prerequisites or failure conditions.

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