initiate_payment

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

With no annotations, the description must disclose behavioral traits. It mentions 'for approval' implying the payment is not immediate, but it does not explain the USSD flow, required authentication (headers), or that the payer must approve via their phone. Important aspects like idempotency or error states are omitted.

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 sentence, concise and to the point. However, it could include a bit more context without becoming verbose, such as acknowledging the approval step or the need for valid phone numbers.

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?

The tool has no output schema, so the description should explain what the tool returns (e.g., a reference ID, status, or confirmation). It does not. Also, the complexity of having 10 parameters (including nested objects) is not addressed. The description is too sparse given the tool's role in payment initiation.

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?

Schema coverage is 100%, so the baseline is 3. The description adds no additional meaning beyond the schema. Each parameter is described in the schema, and the tool description does not elaborate on their usage or relationships.

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 'Send a USSD payment request to a payer's phone number for approval,' specifying the verb (send) and resource (USSD payment request). It distinguishes from sibling tools like initiate_transfer by focusing on USSD-based payment requests. However, it does not mention the mobile money context or that it applies to specific networks.

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 lacks any guidance on when to use this tool versus alternatives such as initiate_transfer or payment_status. No prerequisites or conditions are stated, and there is no mention of when not to use it.

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