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

readOnlyHint=true already establishes this as a safe read operation, so the bar is lower. The description adds the important 'settled' scope and documents the underlying query parameter mapping (category.in, created_at.after/before), but does not state pagination semantics beyond what the schema's cursor field implies. Acceptable but not rich.

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 short sentences, each earning its place: purpose, endpoint, and filter semantics. No filler, no redundancy, and the core scope ('settled transactions') is front-loaded.

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?

For a read-only list tool with full schema coverage and readOnlyHint, the description is sufficient: it names the resource, the endpoint, and the filterable dimensions. It stops short of describing pagination behavior or explicitly ruling out pending/declined transactions, which the sibling list makes relevant.

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 the schema already defines every parameter, including the API-side parameter names. The description reinforces the filter mapping for category and date range but adds no syntax, format, or constraint details beyond the schema. 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 settled transactions') and pins it to the concrete API endpoint GET /transactions. It is distinguishable from siblings by the word 'settled' and by the endpoint, though it does not explicitly contrast with increase_list_pending_transactions or increase_list_declined_transactions, which are the nearest neighbors.

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 says what can be filtered (account, category, date range) but gives no explicit when-to-use or when-not-to-use guidance. With siblings like increase_list_pending_transactions and increase_get_transaction present, the agent must infer that this tool covers settled transactions and that single-transaction retrieval goes elsewhere.

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