get_bill_history

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states 'view' implies a read-only operation, but does not specify authentication needs, rate limits, error handling, or what the output looks like (e.g., format, pagination). For a tool with no annotations, this leaves significant gaps in understanding its behavior.

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 a single, efficient sentence: 'View past Xfinity bills and payment history for a specified number of months.' It is front-loaded with the core purpose and wastes no words, making it highly concise and well-structured.

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 the tool's low complexity (1 optional parameter, no output schema, no annotations), the description is minimally adequate. It covers the basic purpose but lacks details on behavioral aspects like authentication or output format. Without annotations or output schema, more context would be helpful, but it meets the minimum for a simple read operation.

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 input schema has 100% description coverage, with the 'months' parameter documented as 'Number of months of history to retrieve (1–24, default: 6).' The description adds no additional parameter semantics beyond this, as it only mentions 'for a specified number of months' without details. With high schema coverage, the baseline score of 3 is appropriate.

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 purpose: 'View past Xfinity bills and payment history for a specified number of months.' It uses specific verbs ('view') and resources ('bills and payment history'), but does not explicitly differentiate from sibling tools like 'get_account_overview' or 'get_usage_details', which might also involve historical data. The purpose is clear but lacks sibling distinction.

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 provides no guidance on when to use this tool versus alternatives. It does not mention sibling tools such as 'get_account_overview' (which might include billing info) or 'get_usage_details' (which could relate to billing), nor does it specify prerequisites or exclusions. Usage is implied by the purpose but not explicitly defined.

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