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get_pixels

Read-only

Read pixel colors from a rectangular region of an Aseprite sprite, optionally targeting one layer, to inspect exact colors before editing.

Instructions

Read the pixel colours of a region.

Args:
    layer: Read this layer alone instead of the composite. This matters more than
        it sounds: drawing tools write to ONE layer, so the composite is not the
        surface your next edit will act on. A fill whose boundary is drawn on a
        different layer will flood the whole canvas while the composite looks as
        though it should have stopped.
    format: "rows" (default) gives rows of "#RRGGBBAA" strings. "map" gives a
        `legend` of symbol to colour plus one string per row, which is around a
        tenth the size: a 16x16 icon of three colours costs roughly 3,400
        characters as rows and 350 as a map, and defects like a one-pixel offset
        are visible in it at a glance.

The region is capped at 64x64 (4096 pixels) per call to keep responses small, so
read in tiles for bigger areas.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
xNoDefault: 0.
yNoDefault: 0.
frameNoDefault: 1.
layerNo
widthNo
formatNoDefault: "rows".rows
heightNo
filenameYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed18 schema fields changedv0.10.0
    • removedInput schema / properties / filename / title
      Removed value: -"Filename"
    • addedInput schema / properties / format
      Added value: +{
      +  "default": "rows",
      +  "description": "Default: \"rows\".",
      +  "type": "string"
      +}
    • addedInput schema / properties / frame / description
      Added value: +"Default: 1."
    • removedInput schema / properties / frame / title
      Removed value: -"Frame"
    • removedInput schema / properties / height / anyOf
      Removed value: -[
      -  {
      -    "type": "integer"
      -  },
      -  {
      -    "type": "null"
      -  }
      -]
    • removedInput schema / properties / height / default
      Removed value: -null
    • removedInput schema / properties / height / title
      Removed value: -"Height"
    • addedInput schema / properties / height / type
      Added value: +"integer"
    • addedInput schema / properties / layer
      Added value: +{
      +  "type": "string"
      +}
    • removedInput schema / properties / width / anyOf
      Removed value: -[
      -  {
      -    "type": "integer"
      -  },
      -  {
      -    "type": "null"
      -  }
      -]
    • removedInput schema / properties / width / default
      Removed value: -null
    • removedInput schema / properties / width / title
      Removed value: -"Width"
    • addedInput schema / properties / width / type
      Added value: +"integer"
    • addedInput schema / properties / x / description
      Added value: +"Default: 0."
    • removedInput schema / properties / x / title
      Removed value: -"X"
    • addedInput schema / properties / y / description
      Added value: +"Default: 0."
    • removedInput schema / properties / y / title
      Removed value: -"Y"
    • removedInput schema / title
      Removed value: -"get_pixelsArguments"
  2. First observedv0.7.0

TDQS

A4.2/5.0
Behavior5/5

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

Annotations only say readOnlyHint=true and openWorldHint=false; the description adds the hard 64x64/4096-pixel cap, the composite-vs-layer behavioral trap, and the output-format size tradeoff. These are non-obvious behavioral traits beyond what the structured fields declare.

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?

Front-loaded with a one-line purpose, then focused arg guidance; the length is largely justified by the layer and format explanations. The layer passage is slightly discursive, keeping it from a 5.

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

Completeness4/5

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

For an 8-param read tool with no output schema and minimal annotations, it explains the output shapes (rows vs map) and the region cap, which is what an agent most needs. It omits any mention of 'frame' semantics, which is a minor but real gap.

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 50%, and the description compensates well for the two semantically tricky params (layer, format) with usage meaning and concrete size examples. It leaves 'frame', x/y, and width/height entirely to the bare schema defaults, so it does not fully close the coverage gap.

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

Purpose4/5

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

States a specific verb and resource ('Read the pixel colours of a region'), which is enough for an agent to distinguish it from get_palette, get_cel, or get_sprite_info at a glance. It does not explicitly name or contrast a sibling, 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.

Usage Guidelines4/5

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

Gives real decision guidance for two parameters: when to pass 'layer' (because drawing tools write to one layer, so the composite misleads edits) and when to choose 'format: map' (size and defect visibility). It also tells the agent to tile for regions over 64x64. No explicit when-not or alternative-tool routing, so not a 5.

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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