set_plan

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

With no annotations, the description carries the full burden. It discloses that the operation replaces an existing plan, auto-creates the model if missing, and returns the plan drawn with rulers. It does not discuss permissions, reversibility, or side effects beyond replacement, but the core mutation and return behavior are transparent.

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 essential action and result are front-loaded, followed by a dense but organized plan specification. The description is long, but the technical detail is necessary for correct invocation and is not filler.

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 nested-object tool with no annotations and no output schema, the description covers creation, replacement, return value, coordinate conventions, and points to kit_reference for further details. Minor gaps are the semantics of 'name'/'note' and explicit error/failure behavior, but overall it is complete enough for an agent to use correctly.

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?

The input schema provides only a free-form 'plan' object and empty property titles. The description compensates substantially by specifying the full plan grammar: views, shapes, landmarks, sections, axes, mirroring, and subtraction. The 'name' and 'note' parameters are not explicitly explained, but their schema titles are reasonably self-explanatory.

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 opens with a specific verb and resource: 'Set (or replace) a model's plan', and defines what a plan is ('the 2D blockout you model against'). This clearly distinguishes it from sibling tools like get_model, edit_model, or set_reference.

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 description gives clear context: use this tool when setting or replacing a model's plan, and it notes the model is created if it doesn't exist. It also says the returned ruler-drawn plan is for checking proportions before modelling. It does not explicitly contrast with alternatives or state when not to use it, but the intended usage is clear.

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