create_er_diagram

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

With no annotations, the description carries the behavioral disclosure burden. It explains what the diagram contains, that the output is an .excalidraw file, and that the return value is an absolute path. It does not mention overwrite behavior or what happens when output_path is omitted, but these are minor for a generation tool.

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 and front-loaded with a clear summary, followed by a compact Args list and a Returns line. Every sentence adds useful information with no filler or redundancy.

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 tool with one required parameter and a fairly rich input schema, the description is nearly complete: it defines the diagram style, the key inputs, the output artifact, and the return value. The main gaps are the omitted theme parameter and the unspecified default behavior when output_path is null.

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?

Top-level schema description coverage is 0%, so the description's Args section must compensate. It explains entities, relationships, title, and output_path at a basic level, but it omits the theme parameter entirely and does not detail the relationship fields such as cardinality or label, leaving that to the nested 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 states a specific verb and resource: 'Create an Entity-Relationship (ER) diagram.' It further distinguishes the tool by describing database-style entity boxes, attributes, relationship arrows, and cardinality labels, which clearly separates it from sibling diagram tools.

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 clear context: this tool is for ER diagrams, specifically database-style ones with entities and cardinality-labeled relationships. It does not explicitly name alternatives or state when not to use it, but the specialized purpose makes the intended use case evident.

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