List payees

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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld), so the description is free to add genuinely new context: the compact-vs-full return shape and, importantly, that payments and standing orders are created from a payeeAccountUid exposed here. That relationship is not derivable from annotations or schema.

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, front-loaded with the primary action and return shape, followed by the relational context and parameter guidance. No filler or redundancy; every clause carries 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?

With no output schema, the description carries the return-value burden and does so by listing the row fields. Combined with annotations that fully declare the safety profile and a description that covers both parameters, the definition is nearly complete; only explicit sibling routing 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 50% – search is documented in the schema, but detail's enum values are not. The description compensates by explaining both modes ('one compact row' vs 'detail=full returns every field') and restates what search matches. Slightly above the baseline because the undocumented enum is clarified.

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 ('Lists saved payees') and even enumerates the row content (name, payeeUid, payeeAccountUid, sort code/account number). The plural 'list' framing distinguishes it from the singular get_payee sibling, though no sibling is named explicitly.

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?

Provides parameter-level usage hints ('use search to filter', 'detail=full returns every field') but never states when to choose list_payees over get_payee or how it relates to list_payee_payments. Usage is implied rather than scoped with alternatives or exclusions.

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