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

Annotations already establish read-only, idempotent and closed-world behavior, so the bar is lower, yet the description adds real value: the provider fallback ('provider_note says so and the general script is returned') and the conditional outputs (call_by, add_to_calendar) when deal_ends is supplied. It does not describe the shape of the script itself, so not a 5.

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?

Purpose is front-loaded in sentence one, followed by usage examples, param guidance and the fallback rule in a logical order. The seven-example list is long but each example earns its place by covering a distinct bill category, so the size is defensible.

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 5 optional parameters, no output schema and annotations already carrying the safety profile, the description covers the key gaps an agent would otherwise hit: which inputs to combine, the provider-mismatch fallback, and the extra fields triggered by deal_ends. It stops short of describing what the returned script contains or its length/format.

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 description coverage is 100%, so per-parameter meaning, examples and formats are already fully documented in the schema, establishing a baseline of 3. The description only adds the combination rule ('give the bill type, the provider, or both'), which is mildly useful but largely restates the optionality implied by zero required params.

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 first sentence names a specific artifact and goal ('call script to lower a bill'), so an agent knows exactly what it produces. It is clear against the sibling get_call_reminder, but it never explicitly distinguishes itself from get_bill_help, leaving that differentiation to inference.

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 'Use for ...' block gives seven concrete user phrasings that map intent to this tool, which is strong routing guidance for an agent matching a user request. It lacks any explicit when-not-to-use or sibling comparison, so it stops short of a 5.

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