export_mesh_library

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

Annotations only declare destructiveHint=true; the description goes far beyond by disclosing silent overwrite of outputPath, both error conditions (no valid meshes, active runtime session), the return format, and how to clear the session blocker. This is rich behavioral context.

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?

Five dense sentences, zero filler, with the core purpose and the 3D-only constraint front-loaded before parameters and error/return behavior.

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?

With no output schema, the description supplies the return format and count, covers error paths, prerequisite session state, and overwrite risk. Nothing an agent needs to invoke this safely is missing.

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 the parameters are self-documented, but the description still adds semantics the schema lacks: outputPath is overwritten silently and meshItemNames defines a subset vs. all-export behavior. It stops short of adding format detail on scenePath/projectPath.

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?

States a specific verb+resource ('Export a scene of MeshInstance3D nodes as a MeshLibrary .res file') and immediately scopes it ('For grid-based 3D tile palettes only, not 2D scenes'), which sharply distinguishes it from the many scene-manipulation 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?

Gives explicit when-to-use (grid-based 3D tile palettes), when-not (2D scenes), and prerequisite alternatives ('stop_project (or detach_project) clears it'). The routing to sibling tools for the runtime-session blocker is spelled out.

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