Get Africa’s Talking account balance

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

Annotations already declare the read-only, idempotent, open-world, non-destructive profile, so the bar is lower. The description adds genuinely new context: the local API key authentication requirement and the fact that it reads from whichever environment (sandbox or production) is configured, which affects which credentials/balance the agent sees.

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?

Two tight sentences with the core action front-loaded, followed by the prerequisite and return shape. No filler.

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 zero-parameter read tool with no output schema, the description covers the essentials: auth prerequisite and the return content (currency and balance). It could note the environment-selection implication more explicitly, but nothing critical is missing.

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 tool takes zero parameters, so the baseline is 4. The empty schema leaves nothing for the description to clarify, and it correctly adds no parameter discussion.

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 ("Read account balance") and scopes it to the configured sandbox or production application. It is clearly distinct from the write-oriented siblings (at_send_sms, at_send_airtime) and the config reader (at_get_config), though it never explicitly names or contrasts them.

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?

Usage is implied by the read-only balance purpose, and the prerequisite "Requires a local API key" is stated, but there is no explicit when-to-use vs. when-to-use-something-else guidance relative to the sibling tools.

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