draft1-mcp

Edit an existing diagram

edit_diagram

Modify an existing architecture diagram with plain-English instructions, such as 'add a Redis cache', and receive the updated share URL.

Instructions

Apply a plain-English change to a diagram previously created with generate_diagram (e.g. 'add a redis cache between the api and the db'). Returns the updated share URL.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "diagram_id": "<diagram_id>",
      "instruction": "<instruction>"
    },
    "name": "edit_diagram"
  }
}

Input Schema

Name	Required	Description	Default
`diagram_id`	Yes	The diagram_id returned by generate_diagram (or a previous edit).
`instruction`	Yes	The change to apply, in plain English.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 1, 2026

TDQS

A4/5.0

Behavior3/5

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

With no annotations, the description carries the transparency burden. It discloses that the change is applied and that an updated share URL is returned, but it does not mention whether the original diagram is overwritten, whether changes are reversible, or any error conditions. This is adequate but leaves gaps.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences with no redundant phrases. It front-loads the action and purpose, then provides a concrete example and return value, making every word earn its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple, two-parameter tool with no output schema, the description covers the essential context: what it does, an example of the instruction format, and the return value. It could add prerequisites or caveats, but the information provided is sufficient for basic use.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

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 both parameters. The description adds an example instruction, but does not provide additional semantic detail beyond what the schema gives, meeting the baseline for full coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description starts with a specific verb+resource: 'Apply a plain-English change to a diagram previously created with generate_diagram.' It clearly distinguishes this from the sibling generate_diagram by focusing on editing existing diagrams, and includes a concrete example.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'previously created with generate_diagram' gives a clear prerequisite for when to use this tool. However, it does not explicitly state exclusions (e.g., when not to use it) or alternative tools beyond the implicit contrast with generate_diagram.

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

Deploy Server