list_labels

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

No annotations are provided, so the description carries the full transparency burden. It adds context by specifying the scope ('across the authenticated user's transactions') and that it returns all labels, which implies a read-only operation. However, it does not explicitly state that it is read-only, nor does it describe potential pagination, ordering, or absence of labels. Given the trivial nature of a list operation, this is adequate 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?

The description is a single, concise sentence that fully conveys the tool's purpose. It is front-loaded with the action verb 'List' and contains no filler or redundant 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?

For a zero-parameter, read-only list tool with no output schema, the description is sufficiently complete. It states what is returned (all labels) and the scope (transactions of the authenticated user). The only missing detail is the exact format of the response, but since no output schema exists, the description delivers enough context for basic usage.

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?

The tool has zero parameters, so the input schema is trivially covered. The description adds no parameter-specific meaning, but none is needed. The baseline for zero-parameter tools is 4, and the description successfully avoids misleading the agent.

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 states a specific verb ('List'), a clear resource ('all labels'), and a scoping context ('used across the authenticated user's transactions'). It distinguishes itself from sibling list tools (e.g., list_transactions, list_categories) by focusing on labels, which no other sibling tool handles.

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 clearly implies when to use the tool: whenever you need the set of labels attached to the authenticated user's transactions. There are no sibling tools for labels, so no explicit alternatives are required. However, it does not mention when not to use it or any preconditions, but the simplicity of the tool makes this minor.

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