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snapshot_scene

Render a selected region of an Excalidraw room to a PNG image to read hand-drawn content, verify layout after edits, and identify element positions with bounding box details.

Instructions

Render a region of the room to a PNG and see it. Use it whenever the drawing itself is the question: to read hand-drawn content (handwriting, sketched boxes, freehand arrows) that reaches you as point arrays and is otherwise unreadable, to answer "what does this look like", and after moving, spacing or grouping elements to check whether anything still overlaps and the groups read as intended. Select with ids, near (one element and its neighbourhood), or bbox; with no selector the whole scene is rendered. The text block after the image gives the bounding box in scene coordinates, the scale, the pixel size and the ids of the elements drawn, so you can map what you see back to read_scene ids and near queries. Shapes, lines, arrows, freehand strokes and text are drawn flat, without the hand-drawn wobble the canvas shows; images, frames and embeds are drawn as a labelled dashed box and named on a placeholders line.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
idsNoRender only the elements with these ids. A container's bound label travels with it.
bboxNoRegion of scene space to render, and the elements that intersect it.
nearNoElement id to centre on: it and everything within the room's nearbyRadius of it are rendered.
scaleNoPixels per scene unit, 1 by default and at most 3. Raise it to read small handwriting.
maxWidthNoPixel ceiling for the width, 1600 by default. A wider render is downscaled and the text block says so.
maxHeightNoPixel ceiling for the height, 1600 by default. A taller render is downscaled and the text block says so.

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changedv0.7.1
    • changedInput schema / properties / near / description
      Previous value: -"Element id to centre on: it and everything within 250 scene units of it are rendered."New value: +"Element id to centre on: it and everything within the room's nearbyRadius of it are rendered."
  2. Addedv0.7.0

TDQS

A4.7/5.0
Behavior5/5

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

With no annotations, the description carries the full burden of behavioral disclosure and succeeds. It explains the flat rendering style, placeholder treatment for images/frames/embeds, the metadata returned in the text block, and the no-selector default behavior. These are meaningful details the agent needs in order to interpret the result correctly.

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

Conciseness5/5

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

The description is dense but well-organized: purpose first, then usage contexts, selection modes, output metadata, and rendering caveats. Every sentence earns its place, and it avoids repeating what the schema already documents.

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?

Even without an output schema, the description tells the agent exactly what to expect: a PNG plus a text block with bounding box, scale, pixel size, and element ids. It covers default behavior, selector choices, and visual approximations, so the agent has enough context to invoke the tool correctly and interpret the result.

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 coverage is 100%, so the baseline is 3. The description adds selector-level meaning by grouping ids, near, and bbox as alternative selection modes and stating the no-selector whole-scene default. This is useful semantic framing beyond the individual schema descriptions, though much of the per-parameter detail already lives in the 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?

Opens with a specific verb and object: 'Render a region of the room to a PNG and see it.' It also distinguishes itself from sibling tools by explaining that this is for when 'the drawing itself is the question,' and it explicitly connects its output back to read_scene ids, making the tool's niche unambiguous.

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?

Provides rich, explicit when-to-use guidance: reading hand-drawn content, answering what something looks like, and checking overlaps after layout changes. It does not state a direct 'when not to use' rule for alternatives like read_scene, but the reference to read_scene for id mapping makes the boundary clear.

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