Create railings

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

Beyond the annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=false), the description discloses that creation happens 'in one undo step', that unspecified settings inherit the Railing tool defaults, that the story defaults to the current story, and the error/return shape. This is substantive 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?

Dense but front-loaded, leading with the core verb and geometry, then parameters, then a tip and return value. Slightly long as a single block, but nearly every clause earns its place.

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?

No output schema exists, yet the description explains the return value ([{guid, type} | {error}]) and points to get_element_details for sub-element GUIDs. Combined with units, undo semantics, and default-inheritance behavior, it is complete enough for correct invocation.

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 real semantics: coordinates in meters, angles in degrees, z carrying slope, arcs for curves, closing a railing by repeating the first point, and the meaning of height/bottomOffset/reference line side. It lifts parameter meaning above the schema text.

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 ('Creates') and resource ('railings') and immediately scopes it to a reference line, distinguishing it from modify_railings and create_stairs in the sibling list. An agent knows exactly what geometry it produces.

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 a concrete routing tip (use a stair's leftBoundary/rightBoundary from get_element_details as the path to guard a stair) and explains the begin/end vs path choice. It does not explicitly state when NOT to use it (e.g. use modify_railings for existing railings), so it falls short of full 5.

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