viewport.raycast

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

Annotations already indicate this is read-only and idempotent, so the description does not need to cover safety. It does add context about normalized image coordinates and evaluated geometry, but it does not disclose behavior for invalid capture_id, missing geometry, or raycast misses. That is a meaningful but incomplete behavioral picture.

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 description is one tightly worded sentence with no filler. The key operational idea is front-loaded, and every phrase earns its place.

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?

Given the tool's simple input set, existing annotations, and presence of an output schema, the description is mostly complete. The main missing piece is an explicit statement that a viewport.capture must be performed first and its id reused here; 'prior viewport capture' only implies this.

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 0%, so the description must compensate for the schema's lack of per-parameter text. It does clarify that x and y form a normalized image coordinate and that capture_id refers to a prior viewport capture, but it leaves out details like coordinate origin and how to obtain a valid capture_id.

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 names a specific verb ('Resolve') and a specific resource ('a normalized image coordinate against evaluated Blender geometry represented by a prior viewport capture'). This clearly separates it from capture and inspection tools that do not raycast against a previously captured viewport.

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 phrase 'prior viewport capture' implies the tool should be used after viewport.capture, but the description never explicitly states that dependency or mentions when to prefer this tool over alternatives like object.geometry.inspect or scene.inspect. The usage context is clear but the when/when-not guidance is only implied.

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