Draw.io MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states this is an update operation, implying mutation, but doesn't cover critical aspects like permissions needed, whether changes are reversible, error handling (e.g., invalid cell_id or shape_name), or side effects. This leaves significant gaps for an agent to understand the tool's 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 that front-loads the core action ('Updates the visual style') and specifies key constraints ('existing vertex cell', 'match a library shape by name'). There is no wasted verbiage, 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 complexity (a mutation operation with no annotations and no output schema), the description is insufficient. It lacks details on behavioral traits (e.g., error conditions, side effects), usage context relative to siblings, and expected outcomes. For a tool that modifies visual properties, more guidance is needed to ensure correct agent invocation.

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 the schema already fully documents both parameters (cell_id and shape_name). The description adds no additional semantic context beyond what's in the schema, such as examples of shape names or cell_id formats. This meets the baseline for high schema coverage.

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 verb ('Updates') and resource ('visual style of an existing vertex cell'), specifying it applies to an existing cell rather than creating a new one. However, it doesn't explicitly differentiate from sibling tools like 'edit-cell' or 'add-cell-of-shape', which might handle similar visual modifications.

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 like 'edit-cell' or 'add-cell-of-shape'. It mentions updating an existing cell but doesn't clarify if this is the preferred method for shape changes or if there are prerequisites (e.g., the cell must exist).

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