list_direct_debits

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

No annotations exist, so the description carries the full behavioral burden. 'List' implies a read-only operation and the provider restriction is disclosed, but there is no mention of pagination, caching/freshness behavior (despite a 'fresh' param existing), or what happens for unsupported providers.

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?

A single tight sentence with the resource front-loaded and the scope qualifier appended. Zero filler, though it is arguably too terse given the undocumented parameters.

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 annotations, no output schema, and 0% parameter coverage, the description needs to do much more than one sentence. An agent still cannot tell what 'fresh' toggles or when provider_id is required, so the definition is incomplete for correct invocation.

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% across three parameters, so the description must compensate and largely does not. 'On an account' weakly implies account_id, but neither 'fresh' nor 'provider_id' is explained, leaving two of three parameters semantically opaque.

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) and resource (direct debits) scoped to an account, which clearly differentiates it from siblings like list_standing_orders and list_transactions. The 'Open Banking providers only' qualifier further narrows intent. It lacks explicit routing language but the purpose is unambiguous.

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 parenthetical '(Open Banking providers only)' gives an implied applicability condition, which is more than nothing. However, it does not say when to choose this over list_standing_orders or what to do for non-Open-Banking providers, leaving the agent to infer usage.

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