Send Airtime

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

Annotations already indicate destructive/destructiveHint=true. Description adds valuable sandbox behavior disclosure. Does not discuss other aspects like auth or rate limits, but the added sandbox note is useful beyond 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?

Three sentences, each adding distinct value: action, use cases, sandbox note. No fluff, highly efficient.

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 that an output schema exists (return values not needed), the description covers purpose, common usage, and sandbox behavior. Lacks prerequisites or error scenarios, but sufficient for a simple tool with good annotations.

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% and already describes each parameter in detail (including minimum amount in production). Description does not add new parameter information beyond what's in the schema, so baseline 3 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?

Description clearly states action (send airtime top-up) and target (specific network subscribers). Common use cases provided. Distinguishes from siblings like mpesa_stk_push which are for money transfers.

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?

Lists common use cases (NGO incentives, survey rewards, agent payouts) and mentions sandbox mode behavior. Does not explicitly compare to alternatives, but given sibling tools, context is clear.

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