List direct debits

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

readOnlyHint=true already tells the agent this is a safe read, so the description needn't re-establish that. It does add the 'all mandates' scope and the account-level restriction, but says nothing about auth requirements, pagination, or result ordering.

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?

One front-loaded sentence with no filler or redundancy. It is efficient, though the brevity borders on under-specification rather than tight editing.

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?

An output schema exists, so return values need not be described, and the annotation covers the safety profile. Combined with 100% schema coverage, the remaining gap is only the lack of pagination or usage-context detail.

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% with a single required accountUid, so the schema already documents the parameter fully. The phrase 'for an account' merely echoes that scoping without adding format or sourcing detail, making the baseline 3 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 ('Get') and resource ('direct debit mandates') scoped to an account, which plainly separates it from siblings like standing_orders_list and payees_list. It stops short of explicitly naming or contrasting those siblings, but the resource 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?

There is no when-to-use, when-not-to-use, or alternative routing guidance; the description only restates what the tool returns. For a list tool with an obvious sibling set (standing_orders_list, payees_list, cards_list), a sentence on which mandate type this covers would have been cheap and useful.

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