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

With no annotations, the description carries the full behavioral burden and delivers: auth requirement (API key on Authorization header), cost ('Reading costs nothing'), limit ('at most 1000 records'), ordering ('newest first'), detailed return field semantics, deliveryStatus meanings, and a critical caveat about 'pending' on SPT/card rails. Comprehensive and transparent.

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 scope; the dense single paragraph is justified by the complexity (no output schema requires explaining return fields and status codes). Every sentence contributes, though slightly better structure could improve scanability.

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?

Given no annotations and no output schema, the description must explain return values and usage context. It fully describes record fields, deliveryStatus meanings, cost, auth, and alternatives. The only minor omission is pagination behavior, but the stated 1000-record cap suggests completeness.

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 100%, so all three parameters are fully documented in the input schema. The description adds no additional parameter-level semantics beyond what the schema already provides, so the 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 and resource ('List your Router payments: the unified ledger across every service and delegation') with scope and ordering. Explicitly names siblings get_payment_result and get_budget as alternatives, allowing an agent to distinguish it without opening schemas.

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 when-to-use ('reconcile an uncertain payment or find a paymentId') and when-not ('does not return service responses... or the remaining budget'), and names the alternative tools for each case. Nothing is left to inference.

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