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

Goes beyond the annotations by disclosing the state effects (partial leaves invoice open, full marks it paid), the confirmation gate and how to disable it, the 'reaches other people' caution, and the required Cotlet API key. Annotations already flag non-read-only/open-world, so this adds genuine operational context without contradicting them.

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 and outcome semantics, then prerequisites and confirmation guidance. Slightly redundant in restating 'register a payment' twice, but every remaining sentence carries actionable 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?

For a mutation tool with no output schema, the description covers state consequences, prerequisites, confirmation behavior, and auth requirements. Nothing essential for correct invocation 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%, so the schema already documents invoice_number, amount, and payment_date. The description references amount and payment date but adds no format or unit detail beyond what the schema provides, so 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 (register a received payment against a customer invoice) and adds the full/partial distinction. An agent can distinguish this from get_invoice or create_invoice without opening any 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 a clear precondition ('Read the balance with get_invoice first') and explains the two outcome branches. It lacks an explicit contrast with alternative payment-recording paths, but the context and prerequisite are strong.

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