add_flange

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

With no annotations, the description carries the burden and discloses key behavior: proper bend radius, Flat Pattern support, auto-mitering semantics, and the bend-direction rule based on the edge's face side. It does not describe document prerequisites or failure behavior, but the major geometric side effects are well covered.

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 front-loaded with purpose and critical usage constraints, then uses a compact Args block. Although it repeats schema defaults, those repetitions are paired with units and semantic meaning, so they earn their place for a seven-parameter CAD feature.

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?

An output schema exists, so the description need not explain return values. It covers the operation, edge batching, bend direction, and most parameter semantics, but omits the instance parameter and any document/sheet-metal-rule prerequisites, leaving minor operational gaps.

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 only 14%, but the description compensates by documenting six of seven parameters: edge_indices format and find_edges usage, distance in mm, angle in degrees, auto_miter, miter_gap expression semantics, and height_datum options. The remaining instance parameter is documented in the schema itself.

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 and resource ("Add a Sheet Metal Flange") and scope (one or more edges), and explicitly distinguishes it from Extrude. It also explains the sheet-metal-specific behavior (Flat Pattern, bend radius, thickness tie), so an agent can tell what kind of feature this creates.

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?

Names Extrude as the non-sheet-metal alternative and gives a concrete batching rule: put all loop edges in one call so corners auto-miter, because separate calls leave open corners. It also points to find_edges for edge discovery. It does not explicitly state when not to use this tool, but the routing context is clear.

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