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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds genuine behavioral context beyond that: the `include` expansions available and the fact that the returned `id` must be reused as `customer_id` in create calls — a non-obvious contract not visible in the annotations.

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 sentences, front-loaded with what is fetched and how, followed by the downstream id contract and endpoint. No filler; every clause carries information.

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?

No output schema exists, so the description must hint at the return shape; it does so by naming the `id` field, which is the piece agents actually need downstream. It stops short of describing the overall response structure or how embedded `include` data is keyed, which is a minor gap for a read 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%, so both parameters are already documented in the schema. The description paraphrases the include values (omitting tax_entity and custom_field_assignments, which the schema lists) and adds no format or default details, so it only matches the schema baseline.

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 (fetch), resource (one customer), and the key selector (customer number), plus an optional expansion mode. 'One customer' implicitly distinguishes it from kickserv_list_customers, so an agent can route correctly without opening a schema.

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?

Explains the retrieval context and adds a concrete cross-tool usage rule: the returned `id` is what job/task create calls need as `customer_id`. It doesn't explicitly say when to prefer this over kickserv_list_customers or kickserv_get_job, so it falls short of full when/when-not guidance.

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