Update Recurring Transaction

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

The description discloses behaviors beyond the annotations: it states partial-update semantics, explains the effect of is_recurring and is_active, and explicitly denies money movement ('This does not create posted transactions or move money'). It also clarifies the meaning of frequency and base_date formats. This adds significant behavioral context not captured by the annotations (which only note idempotency and non-destructiveness).

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 front-loaded with the core purpose and then details each aspect in logical order. Every sentence adds value: it covers scope, parameter sourcing, update semantics, and exclusions. Though lengthy, it is efficient for a tool with 7 parameters and no schema documentation. No redundant or filler sentences.

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 tool's complexity (7 params, 2 required, no schema docs), the description is remarkably complete. It explains all parameter meanings, required input sourcing, partial update behavior, and non-transaction effects. The output schema exists and likely covers return values, so no omission is evident. The description fully equips an agent to call the tool correctly.

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 input schema has zero descriptions (coverage 0%), so the description must fully document parameter semantics. It does: it explains how to obtain merchant_id, what merchant_name is for, the meaning of each optional field (frequency as Monarch's string, base_date as the anchor, amount as signed value), and the semantics of is_recurring and is_active. This is essential because the schema alone provides no 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 opens with a precise statement of the tool's function: 'Change a merchant's recurring schedule, not an individual transaction.' This clearly identifies the verb (change) and resource (recurring schedule) and differentiates it from transaction-level operations. The statement 'This affects the merchant-wide recurrence' reinforces scope and distinguishes it from siblings like update_transaction.

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 when-to-use guidance: it targets the recurring schedule, not an individual transaction, and clarifies that it does not create posted transactions. It also gives operational instructions for obtaining required parameters (merchant_id from stream.merchant.id) and explains partial update semantics ('Omitted settings stay unchanged; provide at least one'). This is comprehensive guidance that an agent can follow without ambiguity.

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