get_customer

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

The description adds behavioral context beyond the readOnlyHint annotation by explaining that it returns a 'shaped customer' and that detail:'full' includes address and contact details. It doesn't mention raw mode or error behavior, but the readOnly annotation covers safety, and the schema details raw. This is good for a simple read operation.

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 two concise sentences, front-loaded with the main purpose and then providing a key behavioral detail. Every word earns its place, with no unnecessary fluff or repetition of schema content.

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 single-customer retrieval tool, the description combined with the rich schema (100% coverage) and readOnlyHint annotation provides complete context. It covers the purpose, the lookup methods, and the output verbosity, which is all an agent needs to select and invoke this tool effectively.

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?

The schema already has 100% coverage with detailed descriptions for all 4 parameters. The description adds meaning by explaining the lookup via 'id or externalId' and clarifying what detail:'full' provides (address and contact details). This enriches the schema without redundancy, so a score above baseline is warranted.

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 clearly states the tool 'Get a single customer by id or externalId', specifying both the action and the resource. It distinguishes itself from sibling tools like list_customers by focusing on a single customer lookup. The mention of 'shaped customer' and detail levels adds further clarity.

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 context is clear: use this when you need a single customer record identified by id or externalId. It doesn't explicitly compare with alternatives like list_customers, but the phrase 'single customer' implies the distinction. No exclusions are mentioned, but the purpose is unambiguous enough.

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