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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description's real contribution is the note that the customer's API key is never returned — a concrete disclosure about what the response omits. No auth or rate-limit context is given, keeping it off a 5.

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?

One tight sentence plus the endpoint, with the highest-value information (single record, id form, what's included) front-loaded. Every clause carries distinct information and nothing is repeated.

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?

With no output schema, the description compensates by naming the returned fields and the one omitted field (API key), which is enough for an agent to know what it will receive. It does not cover error behavior or what happens when rep_group_id is supplied but irrelevant, a minor gap.

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%, so both parameters are already documented. The '(like B123)' example adds a small amount of format guidance for customer_id, but rep_group_id's manufacturer-account scoping is only in the schema, not the description. Baseline 3 is appropriate.

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 (get) and resource (customer's full record) and enumerates the record contents: addresses, contacts, ship-to locations, terms, pricing method. Adds the endpoint and id format, so it is clearly distinguishable from markettime_list_customers.

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 id-based retrieval and the enumerated contents make it clear this is the single-record fetch versus the sibling list tool. There is no explicit 'use X instead when' statement or note about how rep_group_id scoping changes the lookup, so it stops short of full routing guidance.

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