Provision a sandbox API user

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

Annotations already declare openWorldHint=true and destructiveHint=false, so the description correctly adds non-obvious behavior: the tool is sandbox-enforced, refuses in production, and returns credentials that must be persisted to specific environment variables. It does not say whether calling it twice mints a new key, which matters given idempotentHint=false.

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 tight sentences, with the most important constraint ('SANDBOX ONLY') front-loaded. The 'three curl commands' rationale earns its place by explaining why the tool exists.

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?

With no output schema, the description compensates by saying exactly what comes back (API user and API key) and what the caller must do with it (save to MOMO_API_USER and MOMO_API_KEY). Combined with the production refusal, an agent has everything needed to call it 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?

Schema coverage is 100% and the single parameter is fully documented there ('Not used in sandbox'), so the schema carries the load. The description adds nothing about providerCallbackHost, though it implies the call needs no meaningful input in sandbox.

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?

States a specific verb and resource ('Create an API user and API key in the MoMo sandbox') plus scope ('SANDBOX ONLY'), which no sibling tool covers. An agent can immediately tell this is a credential-bootstrap tool distinct from payment or account operations.

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?

Explicitly scopes usage to the sandbox and states the tool is 'Refused outright in production', which is a clear when-not-to-use signal. It doesn't name an alternative for production, but the description explains why none exists (MTN issues credentials there), which is nearly as good.

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