feature_draft

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

With no annotations supplied, the description carries the full burden and does so: it enumerates the failure modes (angle 0 or >=90, angle2 combined with symmetric, non-planar plane) and states the side effects ('nothing changed' for INVALID_PARAMS, rollback for FUSION_API_ERROR). It also names what gets modified, which is the key behavioral fact for a mutation tool.

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-loaded with the core action, then the planar semantics, then errors, then return shape, then a one-line example — every block earns its place and there is no filler. It is slightly dense in the first two paragraphs, but nothing is redundant.

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 7-parameter mutation tool with no annotations and no output schema, the description supplies everything an agent needs: required upstream step (inspect_query), plane constraints, error taxonomy, rollback behavior, the full return payload keys, and a concrete invocation example.

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 genuine meaning beyond the schema: the mutual exclusivity of symmetric and angle2 (enforced as INVALID_PARAMS), the meaning of the plane's normal as pull direction with flip reversing it, and that angles may be Fusion expressions. Only tangent_chain goes unmentioned.

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?

Opens with a specific verb plus resource ('Tilt faces by a draft angle relative to a neutral plane') and even names the manufacturing domain (moulding / casting draft), so an agent knows exactly what operation this is. It does not explicitly contrast itself with adjacent siblings such as feature_offset_faces or feature_shell, so it stops short of a 5.

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 clear operating context: faces must come from inspect_query, the neutral plane must not be one of the drafted faces, and it explains the three angle modes (single, symmetric, angle2). It also states that flip reverses the pull direction. It lacks explicit when-to-use-this-instead-of-a-sibling routing, which keeps it at 4.

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