add_dimension

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

No annotations are provided, so the description carries the full burden. It does disclose genuinely useful traits: it is a real geometry entity, it costs exactly 'one undo step', and all inputs are in metres. It omits permission/model-state requirements, what happens on invalid points, and what the call returns.

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?

Two tight sentences: the entity type and its scope lead, followed by placement, undo cost, and units. Every clause carries information and nothing is repeated from the schema.

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 mutation tool with no annotations and no output schema, the definition covers the essentials (entity kind, undo cost, units, default tag) but leaves gaps around return value (e.g., the created entity handle) and failure/precondition behavior. Adequate, not complete.

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 50%: tag and offset are documented in-schema, while point_a/point_b have no descriptions. The description partially compensates by pinning the unit system ('all lengths and coordinates are in metres') and by echoing the default tag, but it adds nothing about the offset vector's direction/role or the point array format.

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+resource ('Add a real linear dimension entity') and explicitly disambiguates from the nearest alternative ('not a text label'), so an agent knows this creates an actual measured dimension rather than an annotation string. It stops short of naming/contrasting with sibling tools like measure or create_edge.

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?

Usage context is only implied: the parenthetical '(not a text label)' steers the agent away from one alternative, and the default tag hints at the typical drop layer. There is no explicit when-to-use vs. measure/create_edge guidance and no stated prerequisites (e.g., an open model or a sketch plane).

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