modify_diagram

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

With no annotations provided, the description carries the full behavioral disclosure burden. It transparently notes a critical side effect: output_path defaults to overwriting the input file. It also documents the operations performed (add nodes, remove labels, add connections) and the return value, giving agents a clear picture of the mutation 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 well-structured into Args and Returns sections, with each line earning its place. The examples are compact yet informative, and the key mutation behavior is front-loaded. No filler or redundancy is present.

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 5-parameter mutation tool with no annotations and zero schema description coverage, this description is complete. It covers all parameters, the default overwrite behavior, the optional output path, and the return value. An agent has enough information to select and invoke the tool correctly without inspecting schemas further.

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 0%, so the description must fully compensate, and it does. Every parameter is listed with a concrete shape or example, including add_nodes object format, add_connections from/to pairs, and the output_path default. This adds meaning far beyond the bare input schema.

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 opens with a specific verb and resource: 'Modify an existing .excalidraw diagram.' This clearly distinguishes modify_diagram from the many create_*, import_*, read_diagram, and export_diagram sibling tools. The scope and action are immediately obvious.

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 phrase 'existing .excalidraw diagram' implies this tool is for editing already-created diagrams rather than creating new ones, giving some usage context. However, the description never explicitly states when to choose this tool over alternatives like create_diagram or when not to use it. Guidance is implied rather than stated.

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