bill_graphRender a bill graph as an image for a selected billing period; choose bits for traffic or monthly for transfer per month.
Render a bill graph as an image.
For the underlying numbers rather than a picture, use bill_graph_data.
| Name | Required | Description | Default |
|---|---|---|---|
| bill_id | Yes | Bill ID | |
| graph_type | Yes | Graph type for the current billing period: 'bits' (traffic) or 'monthly' (transfer per month) |
Changes observed during successful MCP inspections.
v1.12.0Input schema / properties / graph_type / descriptionPrevious value: -"Graph type: bits, monthly, hour, or day"New value: +"Graph type for the current billing period: 'bits' (traffic) or 'monthly' (transfer per month)"Input schema / properties / graph_type / enumAdded value: +[
+ "bits",
+ "monthly"
+]v1.11.1Output schema / (root)Previous value: -{
- "additionalProperties": true,
- "type": "object"
-}New value: +nullv1.9.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds that the output is an image, which is useful context, but says nothing about format, size, or rendering behavior beyond that.
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 short sentences, zero waste, and the image-vs-numbers distinction is front-loaded and immediately actionable.
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 read-only, idempotent rendering tool with 100% schema coverage and no output schema, the description covers what the tool returns (an image) and how to get raw numbers instead. Adequate, though it could note the image format or any size limits.
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% and the graph_type enum is documented in the schema with meanings for 'bits' and 'monthly'. The description adds no parameter detail beyond what the schema already provides, so baseline 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?
States a specific verb and resource ('Render a bill graph as an image') and names the sibling it is not (bill_graph_data) with the distinguishing criterion (image vs numbers). Clear, though 'bill graph' is somewhat generic given many *_graph siblings.
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 routes the agent: use bill_graph for an image, bill_graph_data for the underlying numbers. Names the alternative and the condition that selects it, though it doesn't exclude other graph siblings like bill_history_graph.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.