Open a project

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

The annotation destructiveHint=true already signals that this tool modifies state, and the description reinforces this by stating 'replacing the current one'. The description adds the import capability for .sh3d files, which goes beyond the annotation. However, it does not disclose additional behavioral details such as unsaved changes handling or the output format. Since annotations already cover the destructive nature, a 3 is appropriate—the description provides some added context but not rich behavioral insight.

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 a single, well-structured sentence that front-loads the primary action and format support, and clearly states the replacement side effect. Every word earns its place with no fluff or repetition. It is maximally concise while remaining informative.

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 destructive open/import operation, the description covers the file types, the replacement behavior, and the essential purpose. The output schema exists (though not shown), so return-value details are not required. The description does not mention prerequisites (e.g., whether the current project must be saved) or error handling, but these are minor gaps given the simple parameter set and the existing annotations. Overall it is sufficiently complete for an agent to invoke correctly.

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?

The schema provides a description for the 'path' parameter (covering .newera and optionality), but the description adds the .sh3d import format, which is not present in the schema. This gives agents crucial extra information about accepted input types. With 100% schema coverage, the description still adds value by clarifying the import capability, so a 4 is warranted.

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 clear verb-resource pair ('Open a project' / 'import a file') and specifies the file types (.newera, .sh3d). It also states the key side effect ('replacing the current one'), which distinguishes it from related tools like new_home or save_home. The purpose is unambiguous and differentiated from siblings.

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 clearly indicates when to use this tool (opening or importing an existing project) and implicitly contrasts with new_home (creating a new one) and save_home (saving the current one). It does not explicitly name alternatives or state when not to use it, but the context is clear enough for an agent to select it appropriately.

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