update_model

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

The description discloses prerequisites (file must exist), the action (replacing content with new SCAD source), and return values (success status, path, name). It does not explicitly say "overwrites" or cover permissions/error cases, but for a mutation tool with no annotations, this is reasonably transparent.

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 Args/Returns sections and each line provides useful information. It is slightly repetitive ("existing" appears twice in the first two sentences) but overall efficient and front-loaded.

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 simple tool with an output schema, the description covers purpose, usage, parameters, and return values, and references the sibling create_model. It does not discuss edge cases like workspace validation or failure behavior, but the tool is straightforward and the description is sufficient.

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 descriptions are completely absent (0% coverage), and the description compensates by explaining each parameter: name (file name), content (SCAD source code), and workspace (directory, with default). The mention of ctx, which is not in the schema, is a minor inconsistency but does not detract from the meaning of the actual params.

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 uses a specific verb ("Update") and resource ("existing OpenSCAD model file"), and explicitly distinguishes itself from create_model. The purpose is immediately clear and avoids tautology.

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?

It explicitly states that the file must already exist and directs users to create_model for new files, providing a clear when-to-use rule and named alternative. This covers the key usage scenario and exclusion.

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