Detect Recurring Charges

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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds valuable behavioral context beyond annotations: grouping logic, supported cadences, estimated annual cost, and concrete limitations such as missing variable-amount bills and payee spelling variations. No contradiction with annotations.

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 dense but well-organized: the opening sentence states the core function and mechanism, followed by clear use cases, differentiation from a sibling tool, and specific limitations. Every sentence contributes meaningful guidance with no filler.

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 the rich annotations, complete parameter schema, and output schema, the description covers all necessary selection and usage context. It explains when to use the tool, what it cannot detect, and how to avoid misinterpretation, making it fully adequate for correct invocation.

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?

All three parameters are fully documented in the schema with 100% coverage, so the description does not need to repeat them. The description adds some context about exact-amount grouping and cadence detection but does not substantially extend parameter-specific semantics beyond the schema.

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 detects recurring charges from transaction history using a specific mechanism (grouping outflows by payee and exact amount, matching cadence). It also explicitly distinguishes itself from list_scheduled_transactions, making it easy for an agent to select the right tool.

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 provides explicit use cases: subscription audits and 'what am I paying for' questions. It also names the alternative list_scheduled_transactions and explains when that tool is insufficient, plus warns against concluding a subscription was cancelled without verifying payee variants.

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