get_bill_history

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

With no annotations provided, the description carries the full burden. It does disclose the authentication requirement, which is a meaningful behavioral trait, but it does not confirm read-only operation or explain any side effects. The word 'View' implies read-only but is not explicit.

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 two short sentences, front-loaded with the core purpose, and contains zero extraneous information. Every word earns its place.

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 simple view tool with only two parameters and no output schema, the description adequately covers purpose and prerequisites. It mentions that bills include dates and amounts, giving the agent a reasonable expectation of output. It could be enhanced by noting any limitations (e.g., date range or bill status), but it is fundamentally complete.

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 parameter descriptions already explain username and password. The description adds the context that these are AT&T login credentials, but that's redundant with the schema. Since schema fully documents parameters, the baseline of 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?

The description clearly states the tool's function: 'View past AT&T bills including dates and amounts.' This uses a specific verb ('View') and resource ('past AT&T bills'), and it distinguishes from sibling tools like get_usage_details (usage data) and pay_bill (payments).

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 mentions a key prerequisite ('Requires AT&T login credentials') but does not explicitly compare with alternatives or state when to use this tool over siblings. Usage context is implied but not directly communicated.

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