import_merge_scene

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

Annotations only indicate a non-read-only, potentially destructive operation. The description adds valuable behavioral detail beyond that: it explicitly assures the merge does not clear existing objects, explains that the importer is determined by extension, and documents the failure mode (err.class_missing) for missing importers. No contradiction with annotations.

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 short and front-loaded with the most important fact (no scene clearing). The bilingual repetition is somewhat redundant but remains compact and readable, so it does not significantly hurt usability.

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 single-parameter, low-complexity tool, the description covers the operation, the non-clearing safety guarantee, importer selection behavior, and error condition. With no output schema, it could mention the success return value, but this is a minor gap and not necessary for correct invocation.

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 already documents the single 'path' parameter with 100% coverage. The description adds a small amount of extra meaning by implying the path should be a file whose extension determines the importer, but it does not substantially expand on the 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 operation (merge a file into the current scene), explicitly notes that existing objects are not cleared, and explains that the importer is selected by file extension. This distinguishes it from related siblings like scene_merge, import_fbx, and import_obj without needing to inspect their schemas.

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 'without clearing existing objects' phrasing implies when this tool is appropriate versus scene-opening/reset tools, and 'probed from extension' implies generic multi-format use. However, it does not explicitly name alternatives such as import_fbx/import_obj or scene_merge, nor state when to prefer those over this tool.

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