Draw.io MCP Server

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

No annotations are provided, so the description carries full burden. It states 'Only provided fields are modified; unspecified properties remain unchanged', which is useful behavioral context for partial updates. However, it doesn't disclose other important traits like required permissions, error handling, whether changes are reversible, or what happens if the cell_id doesn't exist. For a mutation tool with zero annotation coverage, this leaves significant gaps.

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 two sentences with zero waste. The first sentence states the core purpose, and the second adds crucial behavioral context about partial updates. Every sentence earns its place, and it's appropriately front-loaded with the main action.

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 this is a mutation tool with 7 parameters, no annotations, and no output schema, the description is incomplete. It covers the partial update behavior well but misses other important context like error conditions, return values, or prerequisites. The 100% schema coverage helps, but for a tool that modifies data, more behavioral disclosure would be beneficial.

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 documents all 7 parameters thoroughly. The description adds no specific parameter information beyond what's in the schema. The baseline is 3 when schema does the heavy lifting, and the description doesn't compensate with additional parameter semantics.

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 ('Update properties') and resource ('existing vertex/shape cell by its ID'), making the purpose specific. It distinguishes from siblings like 'add-cell-of-shape' (creation) and 'delete-cell-by-id' (deletion) by focusing on modification of existing cells.

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 implies usage for updating existing cells, but doesn't explicitly state when to use this tool versus alternatives like 'set-cell-data' or 'set-cell-shape'. It mentions 'Only provided fields are modified', which offers some guidance on partial updates, but lacks explicit when/when-not instructions or named alternatives.

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