Create a GDL library part

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

With annotations covering the safety profile, the description still adds real behavioral detail: overwrite:true replaces an existing embedded part of the same name and existing placed instances keep their link and update, which is a non-obvious mutation consequence. It also discloses defaults (type Object / subtype ModelElement, automatic ZZYZX parameter, default script2D), the return shape, and the failure mode ('GDL errors show up as missing geometry').

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 prose is front-loaded (purpose and return first, then usage, defaults, verification, and reference) and every line is information-dense. The embedded GDL quick reference is large, but given there is no output schema and no separate reference resource, it earns its place; the only cost is that the description is long for a tool blurb.

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 an 18-parameter, deeply nested, write-type tool with no output schema, the description covers purpose, defaults, overwrite semantics, return value, verification workflow, and the GDL syntax needed to populate the script fields. An agent has everything required to invoke it correctly and to validate the result.

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 already 100%, so the schema carries most parameter meaning. The description nevertheless adds semantics the schema does not: the automatic ZZYZX height parameter behavior, the default 2D script for objects/lamps, subtype defaults by type, and a full GDL quick reference that makes the scripts/parameters fields usable. This exceeds the baseline 3 but does not re-explain every individual field.

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 opening sentence names a specific verb and resource ('Creates a custom GDL library part ... in the project's EMBEDDED library from GDL scripts and a parameter list') and even states the return shape and the downstream consumers (create_objects / create_lamps). This clearly separates it from sibling placement tools like create_objects, create_lamps, and change_library_part.

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?

'Use it for anything the standard library lacks (custom furniture, built-ins, fixtures, signage, parametric equipment)' gives a concrete when-to-use condition, and the overwrite:true note plus the 'Verify with get_library_part_scripts, then place it' workflow adds practical context. It stops short of an explicit when-not-to-use / alternative (e.g., modify an existing part instead), so it is a strong 4 rather than a 5.

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