Create polylines

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

Annotations declare the write/non-destructive profile, and the description adds substantial context beyond them: active-window targeting, storyIndex defaulting, the constraint that 3D windows cannot hold 2D elements, and the partial-failure return contract. This is exactly the kind of behavioral detail annotations cannot carry.

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?

Dense but well front-loaded: geometry description first, then usage, then window/targeting constraints, then return contract and follow-up tools. Every sentence carries information, though the run-on structure 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?

For a complex creation tool with no output schema, the description covers targeting, defaults, partial-failure behavior, and the return shape ([{guid, type} | {error}] in input order). Nothing essential to correct invocation 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 baseline is 3, but the description adds non-redundant semantics: the arc edge indexing rule and the critical note that modifying 'arcs' or 'closed' requires resending 'points' because geometry is replaced. That goes beyond what the schema states.

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 ('Draws 2D polylines') and details the geometry model (straight + curved segments, open/closed), which distinguishes it from siblings like create_lines, create_arcs, and create_circles. An agent can tell it apart without opening the schema.

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 clear context ('Ideal for outlines, symbols and room-separator chains (zoneBoundary: true)') and names follow-up tools (modify_elements, get_element_details). It stops short of explicitly saying when to prefer this over create_lines/create_arcs, only noting shared style fields.

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