uv_pack_islands

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only says 'Pack UV islands to fill the UV space efficiently,' which implies a modification of UV layout but does not mention side effects, reversibility, permission requirements, or any consequences for existing UV data. This is a mutation tool, and the description omits important 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?

The description is concise and well-structured with an 'Args' section listing parameters. Every sentence carries meaning, and it is appropriately short for a simple tool. It avoids redundancy and is easy to parse, though the 'Args' section could be tightened.

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?

The tool is relatively simple (3 params, one required) and the description covers the core operation and parameter meanings. However, it lacks guidance on when the tool is applicable (e.g., object must have existing UVs) and does not mention what the tool returns or if it has side effects. With no output schema and no annotations, these omissions leave gaps for an agent deciding to use it.

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 description provides semantic meaning for each parameter beyond the schema (e.g., 'object_name: Target object', 'margin: Margin between islands', 'rotate: Allow islands to rotate'). However, the explanations are minimal; for instance, it does not specify units for margin or the exact effect of rotate. Given the 0% schema coverage, the description partially compensates but could be more detailed to fully disambiguate parameter use.

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 action ('Pack UV islands'), the resource ('UV islands'), and the goal ('fill the UV space efficiently'). It distinguishes itself from sibling UV tools like uv_smart_project, uv_unwrap, and uv_project_from_view by focusing specifically on packing rather than unwrapping or projecting, making the purpose unambiguous.

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?

There is no guidance on when to use this tool versus alternatives. It does not mention any prerequisites (e.g., the object must already have UVs), nor does it exclude scenarios where other UV tools should be used. The description simply states the action without contextual usage direction.

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