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Caption a TOP (is the output alive?)

caption_top
Read-only

Render a preview of a TouchDesigner operator and generate a plain-text caption with color stats to verify the network is rendering correctly, using vision or histogram analysis.

Instructions

Read-only: render a TOP's preview and return a plain-text description of it — the headless 'is the output alive?' primitive. Two paths: (a) a configured vision LLM endpoint when available, (b) a DETERMINISTIC luma/colour-histogram fallback decoded from the preview PNG pixels (always works, no model needed). Reports dominant colours, mean luma, near-black fraction, a coarse classification ('black'/'very dark'/'dark'/'bright'/'colorful'/'mid'), and a friendly caption. Returns {node_path, width, height, source:'vision'|'histogram', caption, stats{...}, warnings}. Use it after a build to confirm the network is actually rendering instead of a black frame. The vision path is currently inert (no vision field on the tool context) and falls back to the histogram.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
node_pathYesPath of the TOP to caption.
widthNoWidth to render the preview at before describing it. Smaller is faster.
heightNoHeight to render the preview at before describing it. Smaller is faster.
use_visionNoUse the configured vision LLM endpoint when available; else fall back to a deterministic histogram description.
Behavior5/5

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

Annotations declare readOnlyHint and destructiveHint; description adds implementation details (vision vs histogram), fallback behavior, and return structure. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Single paragraph front-loads purpose, then explains paths, return, and usage. Generally efficient, though slightly verbose in listing return fields.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 4 parameters, no output schema, the description explains return structure, usage context, and warns about vision path inertness. Fully sufficient for this simple tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema covers 100% of parameters, description adds context like 'Smaller is faster' for width/height and explains use_vision behavior, adding value beyond schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb (render/describe), resource (TOP preview), and scope (check if alive). It distinguishes itself from sibling tools which are mostly creation or other utilities.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly says to use after a build to confirm rendering, not just black frame. Mentions two paths and that vision is currently inert. Does not list alternatives but context is clear.

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

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