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

The readOnlyHint annotation already tells the agent this is a safe read, so the bar is lower. The description adds that attribution data is included in the response, which is useful context, but it discloses nothing about not-found behavior, auth requirements, or response shape beyond that one field mention.

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 sentences, front-loaded with the operation and payload, followed by the REST endpoint reference. No filler, though the endpoint string is low-value for an agent that never sees raw HTTP.

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 tool with annotations covering safety, the description is nearly sufficient. Because there is no output schema, the brief note that attribution comes back with the customer is doing real work in setting response expectations, though it is thin given no field-level detail.

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% with a single documented parameter, so the schema already fully explains customer_id. The description adds no syntax, format, or sourcing detail about the id beyond what the schema provides, so the baseline 3 applies.

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 ('Fetch a single customer') and adds the returned payload scope ('with their attribution'). The word 'single' implicitly distinguishes it from the sibling dub_list_customers, but that alternative is never named, so the differentiation is left to inference.

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 singular-resource framing and the required customer_id, which together signal a lookup-by-id operation. There is no explicit statement of when to use this versus dub_list_customers, and no prerequisites or error conditions are mentioned.

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