list_spending_sources

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

With no annotations, the description carries the burden of disclosing behavior. 'List all payment sources' clearly implies a read-only, non-mutating operation with no filtering. However, it does not describe the response shape or any edge behavior like empty results, which would help the agent use the returned data in subsequent create calls.

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 sentence that leads with the action and resource, then adds only the essential purpose. Every word earns its place; there is no filler or redundancy.

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 list tool, the description is adequately complete: it states what is listed and why it is needed. A minor gap is that it does not mention what fields the returned payment sources contain, but the absence of an output schema and the simplicity of the operation keep this from being a serious omission.

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 and the input schema. The description adds context about why these sources are needed, which is enough. With no parameters to document, the baseline of 4 applies.

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 verb 'List' and the resource 'payment sources', and it adds the purpose 'needed for creating expenses and incomes'. It is distinguishable from nearby siblings like list_spendings and list_spending_categories, though it does not explicitly name them.

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 '(needed for creating expenses and incomes)' gives clear context on when to use this tool: before creating spending or income records. It does not provide exclusions or name alternatives, but the context is sufficient for a zero-parameter lookup.

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