render_diagram

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

Annotations already provide idempotentHint=true and readOnlyHint=false. The description adds that auto-layout runs by default with semantics similar to save_model, but does not clarify whether auto-layout modifies the model or is purely computational. It also omits error conditions. The description adds some context but not exhaustive.

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?

Two sentences with no extraneous words. The first sentence immediately states the purpose, and the second sentence provides additional behavioral details. Each sentence earns its place.

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?

The description covers purpose, output format, file option, and default auto-layout. It lacks details on what happens when model_id is not provided (assumes current model) and error handling, but for a tool with three optional parameters and no output schema, this is largely sufficient. Minor gaps prevent a 5.

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 coverage is 100%, so baseline is 3. The description adds that filepath is optional, auto_layout defaults to true, and model_id defaults to the current model. It also notes that auto_layout has 'same semantics as save_model', adding a bit beyond the schema. No further elaboration.

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 action (Render), resource (current model), output format (SVG), and diagram type (stock-and-flow). It also mentions inline return and optional file writing. This distinguishes it from sibling tools like read_model or get_model_xml.

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 context on when to use filepath (for clients with file access) vs inline (for those without), and notes the default auto-layout behavior. However, it does not explicitly mention when not to use the tool or alternative approaches, but the guidance is clear.

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