blender_mesh_mark_seam

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

With no annotations provided, the description carries the burden of behavioral disclosure. It does explain the consequence of marking seams ('define where the UV map is cut for unwrapping'), which is useful. However, it omits operational traits: that this mutates mesh data, that marking only affects UV unwrapping and not geometry, and how clearing interacts with previously set seams.

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?

Three short sentences, front-loaded with the action, followed by a clear conceptual explanation and a one-line purpose statement. No redundancy or filler. It could earn a 5 only if the 'Essential for texture mapping preparation' sentence carried more actionable detail.

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?

Adequate for a simple four-parameter tool whose schema is fully documented: the agent knows what the operation is, what UV seams are for, and how to pass parameters. Gaps remain: no guidance on when to choose manual seam marking over automated unwrapping, and no explicit workflow note about selecting edges in the viewport first. Since there is no output schema, the description also doesn't need to explain return values.

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 description coverage is 100%, so the schema fully documents all four parameters including the edge_indices/selected_only fallback behavior. The description adds conceptual background about UV seams but no additional parameter-level meaning, matching the baseline of 3.

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 specific verb+resource pair ('Mark or clear UV seams on edges') and adds conceptual context explaining what UV seams do, which distinguishes it from related edge tools like blender_mesh_mark_sharp or blender_mesh_crease. However, it does not explicitly name sibling tools or state why it differs from them, stopping short of a 5.

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 phrase 'Essential for texture mapping preparation' gives implied usage context for when an agent should reach for this tool. But there is no explicit when-to-use vs when-not-to-use guidance, no mention of alternatives like the auto-UV tool, and no workflow prerequisites (e.g., select edges first or pass edge_indices).

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