Validate and render Mermaid diagrams to PNG or SVG from source or structured JSON IR, returning the Mermaid source and image. Fails on render errors.
Validate and render a diagram with Mermaid CLI 12. Pass ir (preferred) or Mermaid source. Returns the Mermaid source plus PNG image (and SVG if requested). Fails on render errors.
| Name | Required | Description | Default |
|---|---|---|---|
| ir | No | ||
| theme | No | ||
| source | No | ||
| target | No | ||
| formats | No | ||
| save_dir | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and idempotentHint, so the description need not repeat those safety traits. It adds useful behavioral context: it 'Fails on render errors' and returns the Mermaid source plus PNG (and SVG if requested). Though it omits details about file saving via save_dir, the description does not contradict annotations and adds value beyond the structured fields.
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, front-loading the core action and input method. It avoids redundant words but could be structured to list parameters more clearly. It is concise enough to be quickly parsed, though not perfectly organized.
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, no output schema, and no schema descriptions, the description is far from complete. It covers the input source and the return format, but misses the output formats configuration, save directory, theme selection, and any relationship to sibling tools. An agent would need to inspect the schema (which has no descriptions) or guess, making the tool hard to use correctly without additional information.
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?
With 0% schema description coverage, the description must compensate but only explains two of the six parameters: 'ir' and 'source'. It does not address theme, target, formats, or save_dir, leaving the agent blind to their purpose and acceptable values. This is a significant gap for a tool with six parameters.
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 identifies the verb ('Validate and render') and the resource ('a diagram'), and specifies the Mermaid CLI 12. It distinguishes this tool from siblings like from_ir (likely converting IR to source) and list_ir_targets by focusing on the rendering step, making its purpose unambiguous.
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?
It provides guidance on input selection ('Pass ir (preferred) or Mermaid source'), implying when to use which form. However, it does not explicitly compare with sibling tools or state conditions when one should use this instead of alternatives. The context is clear enough for an agent to infer the right usage in most scenarios.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.