Render Chart.js configurations into PNG images server-side for bar, line, pie, radar, and other chart types, enabling chart images without a browser.
Render a Chart.js configuration into a finished chart PNG, server-side – bar, line, pie, radar and all other Chart.js types. $0.01.
| Name | Required | Description | Default |
|---|---|---|---|
| width | No | ||
| config | Yes | Chart.js config: {type, data, options} | |
| height | No | ||
| background | No | ||
| output_path | No | ||
| idempotency_key | No |
Changes observed during successful MCP inspections.
v0.6.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It discloses server-side execution and a cost of $0.01, but does not state whether the operation is read-only, whether it writes files when 'output_path' is provided, or any error/rate-limit behavior. A mutation or file-writing side effect is unaddressed.
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, front-loaded sentence that achieves maximum information density: action, target, output format, server-side context, chart-type coverage, and cost. No filler or redundancy.
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 six parameters, one nested object, no output schema, and no annotations, the description is too sparse. It fails to explain parameter effects (e.g., output_path behavior), idempotency, or return value expectations. A competent agent would need to inspect the schema and guess, which is incomplete for production use.
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 only 17%, so the description must compensate, but it adds little beyond the config parameter. It mentions 'Chart.js configuration' which mirrors the schema description, and no light on width, height, background, output_path, or idempotency_key. The tool is not usable correctly without external knowledge of these 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 description states a specific verb ('Render') and resource ('Chart.js configuration into a finished chart PNG') with clear output type, and enumerates chart types ('bar, line, pie, radar') to convey scope. It distinguishes itself from generic siblings like 'render' by being chart-specific and server-side.
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?
No explicit guidance on when to use this tool versus alternatives. It implies usage (render Chart.js configs) but does not mention sibling tools like 'render' or provide conditions for selection. The 'server-side' hint gives slight context but no exclusion criteria or recommendations.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.