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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral context beyond that: pagination behavior ('Pages hold 1 to 100 customers; pass next_cursor back as cursor'), the account-scoping of results, and an auth requirement (Cotlet API key with app access).

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 purpose, then scope, downstream usage, pagination, and auth in sequence. It is a touch dense and the opening fragment ('Customers in your Pennylane account with name, type and email') is slightly ungainly, but no sentence is wasted.

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, and the description compensates by describing the returned fields (name, type, email) and the pagination envelope. Combined with the auth note, it is nearly complete, though it does not describe total counts or ordering.

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 the baseline is 3. The description still adds value by explaining the pagination contract and clarifying that the response's next_cursor feeds the 'cursor' parameter, which resolves a naming mismatch the schema alone doesn't make explicit.

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 (list) plus resource (customers) and scopes it ('in your Pennylane account you signed in with, company and individual customers alike'), and it names the returned fields. An agent can distinguish it from sibling create_customer and list_customer_invoices 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?

Explicitly routes downstream use ('Use customer_id from each item in create_customer_invoice and list_customer_invoices') and notes the optional name filter. It stops short of stating when NOT to use it or naming the sibling read tools as alternatives, so it is clear context rather than 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.