merge_mesh_files

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

No annotations are provided, so the description carries the full burden. It discloses important behavioral traits: the operation is simple concatenation (no positioning logic), and it opens an interactive 3D stage on success, with automatic decimation of oversized meshes for display. This goes beyond the basic operation and manages expectations about the inline viewer and preview 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: it opens with a clear one-line summary, immediately provides usage guidance, then lists the parameters in a compact docstring format, and ends with an explanatory note about the 3D stage. It is mostly front-loaded with the most critical info (what it does and when to use an alternative). The note about the 3D stage is a bit verbose but adds useful context about a side effect that could surprise the user.

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?

Given that there is no output schema, the description mentions that the tool returns a dict with merge statistics, which covers the return value. It also explains the side effect (opening the 3D stage) and notes that oversized meshes are decimated. The description covers the tool's core purpose, parameters, alternatives, and side effects. It could mention error handling or file format limitations, but for a relatively simple concatenation tool, it is reasonably complete.

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 input schema has 2 parameters with 0% description coverage, meaning the schema only provides type information (array of strings, string) without descriptions. The description adds a sentence listing `file_paths` and `output_path` and explains their roles ('List of STL file paths to merge', 'Destination path for the merged file'). This is basic but adequate; it doesn't add details like accepted formats, file size limits, or path resolution rules. The description does not fully compensate for the schema's lack of detail, so a baseline 3 is appropriate.

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 tool's function: 'Combine multiple STL files into a single mesh file (simple concatenation)'. It uses a specific verb (Combine), resource (STL files), and clarifies the scope (simple concatenation). It also distinguishes itself from the sibling tool `merge_stl`, which handles positioning with x/y/z offsets. This is a precise, unambiguous purpose.

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 explicitly guides usage: 'For positioning parts with x/y/z offsets, use ``merge_stl`` instead.' This directly points to an alternative tool and clarifies when not to use this one. It also adds context that this is useful for 'composing multi-part designs into one printable file', giving a clear use case.

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