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Draw

draw

Apply multiple drawing operations to a pixel art cel in one undoable transaction. Enables drawing shapes, lines, fills, gradients, and blits with palette snapping and selection clipping.

Instructions

Apply a batch of drawing operations to one cel, as a single undoable action. Ops: pixels, line, polyline, rect, ellipse, fill, replace, dither, gradient, clear, blit. Batch aggressively — a whole sprite in one call is normal and correct, and it means the user can undo your work with one Ctrl+Z. Set paletteLock (default true) to snap every colour to the sprite's palette by perceptual distance before anything is written, so you cannot silently widen a curated palette. Ops run in array order, so paint fills before outlines and outlines before highlights.

Input Schema

TableJSON Schema

Name	Required	Description
`ops`	Yes	Applied in order, in one transaction.
`frame`	No	1-based frame number. Omit to use the active frame.
`label`	No	Name shown in Aseprite's undo history. Describe the intent, e.g. 'shade helmet'.
`layer`	No	Layer name. Omit to use the active layer.
`sprite`	No	Which sprite: its id as '#7' (what every result reports back, and the only unambiguous form — two unsaved documents are both called 'Sprite'), its filename, or its display name. Omit to use the sprite Aseprite has focused.
`createCel`	No	Create the cel if the target layer/frame has none.
`paletteLock`	No	Snap every colour to the nearest palette entry (CIELAB ΔE). Set false only when the user asked to introduce new colours.
`selectionOnly`	No	Clip every op to the current selection.

Output Schema

TableJSON Schema

Name	Required	Description
`frame`	Yes
`layer`	Yes
`bounds`	No	Bounding box actually touched.
`sprite`	Yes
`opsApplied`	Yes
`colorsSnapped`	Yes	Colours palette-lock moved, and how far. A large ΔE means the palette lacks that colour.
`pixelsChanged`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.1.6Sep 9, 2026

changedInput schema / properties / sprite / description

Previous value: -"Sprite filename or id. Omit to use the sprite Aseprite has focused."New value: +"Which sprite: its id as '#7' (what every result reports back, and the only unambiguous form — two unsaved documents are both called 'Sprite'), its filename, or its display name. Omit to use the sprite Aseprite has focused."

First observedv0.1.0Sep 8, 2026

TDQS

A4.7/5.0

Behavior5/5

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

Although annotations already indicate this is a mutating (readOnlyHint=false) and non-idempotent tool, the description adds rich details: it modifies the cel, creates cels when needed (createCel default), respects paletteLock with CIELAB snapping, clips ops to selections, and records undo history. These side effects are fully disclosed.

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 compact yet information-dense, covering all essential operational details in a few sentences. It avoids extraneous fluff, and each sentence adds value regarding batching, paletteLock, or execution order.

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 the tool's complexity and the presence of an output schema, the description fully covers necessary context: how to use it, side effects, transaction semantics, and configuration options. It does not need to explain return values because the output schema exists, and all operational aspects are addressed.

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

Parameters3/5

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

The schema already covers 100% of parameters with inline descriptions (e.g., colour format, per-pixel fallback, tolerance, ratio meanings). The prose outside the schema does not add significantly to parameter understanding; it reiterates paletteLock behavior already described in the schema. Thus baseline 3 is appropriate.

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 tool applies a batch of drawing operations to a cel as a single undoable action, with a specific resource (cel) and operation types. It distinguishes itself from sibling tools focused on reading, selecting, or transforming.

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

Usage Guidelines5/5

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

The description explicitly advises batching operations aggressively, explains the ordering of ops, and gives concrete guidance on when to set paletteLock to false ('only when the user asked to introduce new colours'). It also clarifies transaction semantics for undo.

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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