billy_list_bank_lines

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

With no annotations, the description carries the full burden. It correctly identifies the tool as read-only and notes the default filtering behavior. However, it does not disclose other important behaviors such as pagination limits, error handling, or what happens when no results are found.

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?

The description is extremely concise with two short sentences. It front-loads the main purpose, then adds critical details (read-only, required parameter, default state). No wasted words.

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 6 parameters and no output schema, the description is adequate but leaves gaps. It covers the key behavioral aspect (unmatched default) and a required parameter, but omits return format, pagination behavior, and other parameter details. For a list endpoint, it is minimally sufficient but not complete.

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?

Only 33% of parameters have schema descriptions (e.g., accountId has a helpful note). The tool description adds context for isMatched (default unmatched) but does not explain page, pageSize, sinceDate, or untilDate. Given low schema coverage, the description should provide more parameter guidance.

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?

The description clearly states the tool lists bank statement lines, specifying the resource ('bank lines') and default behavior (unmatched). It distinguishes itself from siblings like billy_get_bank_line (single line) and billy_list_bank_payments (different resource) by the resource type and scope.

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 mentions it's read-only, requires accountId, and defaults to unmatched lines, providing basic usage context. However, it does not explicitly guide when to use this tool versus alternatives like billy_get_bank_line or billy_list_bank_payments, nor does it mention when to set isMatched to true.

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