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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so safety is covered. The description adds real value beyond that: the exact content returned and the auth prerequisite ('needs the user's Cotlet API key with access to this app'). No detail on rate limits or pagination, but auth and read scope make this more than adequate.

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?

Front-loaded with the resource and its contents, then usage guidance, then auth. Efficient overall, though the first and second sentences partially overlap in listing the customer's attributes (addresses, contacts, notes, jobs), which is minor redundancy.

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 correctly explains the return payload (addresses, contacts, special instructions, notes, jobs with status), and it adds the auth requirement and pre-create-job usage cue. For a 1-param read tool with full annotation coverage, nothing an agent needs is missing.

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% and the single parameter (customer_number) is already documented in the schema as coming 'from list_customers.' The description adds no further parameter meaning, so the baseline 3 applies - the schema carries the burden here.

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+resource ('Get one customer') and enumerates the returned sub-resources (service/billing addresses, contacts, notes, jobs with status). The singular scope ('One customer') clearly separates it from the sibling list_customers. An agent can tell exactly what this fetches without opening the 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?

Gives explicit usage context: 'Use it before creating a job so your agent reuses the right contact.' This tells the agent when to reach for this tool, though it doesn't name create_customer/create_job directly as alternatives or state any exclusions.

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