Excalidraw MCP Server

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

With no annotations provided, the description carries full burden but offers limited behavioral insight. It states this is an update operation (implying mutation) and mentions multi-session targeting, but doesn't cover permissions, error conditions, rate limits, or what happens to unspecified attributes. For a mutation tool with zero annotation coverage, this is inadequate.

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 well-structured with a clear opening sentence followed by bullet points for attributes and a final note on multi-session support. It's appropriately sized without unnecessary elaboration, though the attribute list could be more concise given the comprehensive schema.

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 mutation tool with no annotations and no output schema, the description is incomplete. It doesn't explain what the tool returns, error handling, or important behavioral aspects like whether updates are partial or complete. The context signals show complexity (nested objects, 3 parameters), but the description doesn't adequately address this complexity.

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 parameters thoroughly. The description lists some updatable attributes (e.g., x, y, text) and mentions sessionId targeting, adding minimal context beyond the schema. This meets the baseline for high schema coverage but doesn't provide significant extra value.

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' and resource 'existing element', making the purpose immediately understandable. It distinguishes from siblings like 'delete_element' by focusing on modification rather than removal, though it doesn't explicitly contrast with other update-like tools if they exist.

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 minimal guidance on when to use this tool. It mentions 'Multi-session support' but doesn't explain when to use this versus alternatives like 'add_elements' for new elements or 'get_scene' for viewing. No prerequisites or exclusions are stated.

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