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

Annotations already declare destructive, non-idempotent, open-world behavior, and the description adds concrete operational context: wallet funds are spent, the external transaction is irreversible, and duplicate same-MSISDN-and-amount requests within 5 minutes return HTTP 409. That is exactly the extra context the annotations cannot express.

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?

Five sentences with no filler. Usage and prerequisite come first, then cost and irreversibility, then retry and duplicate handling — each sentence carries distinct operational value.

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?

For a destructive, non-idempotent mutation tool with an output schema, the description covers authentication context, the prerequisite data lookup, financial and irreversibility warnings, retry policy, and duplicate behavior. Nothing material is missing 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?

Schema coverage is 100%, so the baseline is 3. The description still adds cross-parameter meaning: the network and amount must come from list_data_products, and the duplicate rule keys on the MSISDN-and-amount pair. It does not add detail for the reference parameter, but the schema already covers it.

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 ('send a confirmed South African mobile data bundle') and scopes it to an authenticated SIMcloud user, which cleanly separates it from create_airtime_order, create_electricity_order, and create_vas_order. An agent can identify the tool without opening the schema.

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 names the prerequisite call (list_data_products first) and the condition for using it (user asks to send a confirmed bundle). It also gives a hard usage exclusion: never automatically retry an ambiguous result.

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