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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds the underlying REST endpoint (GET /customers/{token}), which is mildly useful context but does not mention error behavior (e.g., 404 for unknown token) or the shape of the returned customer.

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 fragments with zero waste, leading with the scope and following with the endpoint. Nothing extraneous is included.

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 one-parameter read-only getter with full schema coverage and complete annotations, no output schema, this is largely sufficient. The only gap is the absence of any error/not-found guidance, which is minor for such a simple 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 100% and the single parameter documents the token format with an example, so the schema carries the parameter semantics. The description's '(cus_...)' reinforces the prefix but adds nothing beyond the schema.

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 resource (customer) with a singular scope ('One customer by token') and gives the token prefix, making it distinguishable from the sibling list_customers. It omits an explicit verb in the description text, relying on the title 'Get customer' to convey retrieval.

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 singular framing ('One customer by token') implies use when the token is known, contrasting implicitly with list_customers. However, there is no explicit when-to-use statement, no mention of alternatives such as list_customers, and no note on what to do if the token is unknown.

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