Place Family

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

Annotations already flag a non-read-only, non-idempotent, destructive operation; the description adds real behavioral detail beyond them — dry_run executes then rolls back and returns the same verification block, unknown/ambiguous document references are rejected before any change, and missing families return similar names with categories. It stops short of explaining what a placement disrupts or how existing geometry is affected.

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?

Front-loads the core operation in one sentence, then uses short paragraphs for name resolution, units, dry_run, and document disambiguation. Efficient overall, though the phantom roomCenterMm line is wasted/inaccurate content.

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 8-parameter, 5-required mutation tool with rich annotations and an output schema, the description covers the highest-risk semantics — naming/type resolution, units, dry-run rollback, and document targeting. It leaves level semantics and failure/rollback behavior for real (non-dry-run) placements unexplained, and the schema-absent roomCenterMm mention slightly undercuts completeness.

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?

With only 13% schema description coverage, the description carries the burden well: it documents family ('name' or 'Family: Type', case-insensitive), type_name null semantics and type-conflict rejection, XY units in millimetres, and rotation in degrees. However, it references 'roomCenterMm', a parameter that does not exist anywhere in the input schema, which could mislead an agent attempting that argument.

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 ('Place a loaded unhosted family on a named level') plus the purpose ('for layout'), which cleanly separates it from siblings like revit_move, revit_edit_families, and revit_list_instances. An agent can identify the operation 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 concrete usage conditions: null type_name falls back to the embedded/first type, conflicting types are rejected, missing families return near-matches, dry_run rolls back, and document must be passed to disambiguate multiple open models. It does not, however, say when to prefer this over alternatives such as revit_batch or revit_move for positioning.

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