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 useful behavioral context: results are ordered newest first, each payment includes the invoice it was applied to, and the tool is paginated. This goes beyond the annotations and helps the agent understand what to expect.

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?

Three sentences with no waste. The core function is front-loaded, followed by ordering/relationship details, then concrete use cases. Every sentence earns its place.

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?

The tool has an output schema, so return values are covered there. The description covers ordering, invoice association, pagination, and use cases. It doesn't mention filtering capabilities, but the filter parameter is structurally self-evident. For a read-only list tool with annotations and output schema, this is reasonably complete.

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 0%, so the description carries the burden for parameter meaning. However, the description doesn't explain any of the three parameters (filter, pageSize, pageToken). The filter object's nested properties (ids, types, statuses, accountId, companyId) are self-descriptive from their names, but the description adds no parameter-level guidance. Baseline 3 is appropriate because the schema structure is fairly clear, but the description doesn't compensate for the 0% coverage.

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?

The description states a specific verb and resource: 'Lists payments a company has received, newest first, each with the invoice it was applied to.' This clearly identifies the tool's function and distinguishes it from payment_get_payment (singular) and other list tools. It doesn't explicitly name a sibling, but the scope is clear enough.

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 description provides clear use cases: 'Use this to answer "what has come in" or to reconcile an invoice against what was actually collected.' This gives context for when to use the tool, though it doesn't explicitly state when not to use it or name alternative tools.

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