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mirror_layer

Create symmetric pixel art by copying one half of a layer onto the other horizontally or vertically, with control over the source side and mirror axis.

Instructions

Mirror one half of a layer onto the other (build symmetric artwork).

Args:
    direction: "horizontal" (reflect left<->right) or "vertical" (top<->bottom).
    source_side: which half is copied: "first" (left/top) or "second" (right/bottom).
    axis: mirror line position (x for horizontal, y for vertical); default = centre.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "filename": "<filename>",
      "layer": "<layer>"
    },
    "name": "mirror_layer"
  }
}

Input Schema

Name	Required	Description	Default
`axis`	No
`frame`	No	Default: 1.
`layer`	Yes
`filename`	Yes
`direction`	No	Default: "horizontal".	horizontal
`source_side`	No	Default: "first".	first

Schema Changelog

Changes observed during successful MCP inspections.

Changed13 schema fields changedv0.10.0Oct 4, 2026
- removedInput schema / properties / axis / anyOf
```
Removed value: -[
-  {
-    "type": "integer"
-  },
-  {
-    "type": "null"
-  }
-]
```
- removedInput schema / properties / axis / default
```
Removed value: -null
```
- removedInput schema / properties / axis / title
```
Removed value: -"Axis"
```
- addedInput schema / properties / axis / type
```
Added value: +"integer"
```
- addedInput schema / properties / direction / description
```
Added value: +"Default: \"horizontal\"."
```
- removedInput schema / properties / direction / title
```
Removed value: -"Direction"
```
- removedInput schema / properties / filename / title
```
Removed value: -"Filename"
```
- addedInput schema / properties / frame / description
```
Added value: +"Default: 1."
```
- removedInput schema / properties / frame / title
```
Removed value: -"Frame"
```
- removedInput schema / properties / layer / title
```
Removed value: -"Layer"
```
- addedInput schema / properties / source_side / description
```
Added value: +"Default: \"first\"."
```
- removedInput schema / properties / source_side / title
```
Removed value: -"Source Side"
```
- removedInput schema / title
```
Removed value: -"mirror_layerArguments"
```
First observedv0.7.0Jul 29, 2026

TDQS

B3.3/5.0

Behavior3/5

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

Annotations already declare readOnlyHint=false and openWorldHint=false, so the agent knows this mutates local state. The description implies the opposite half is overwritten by 'mirror onto the other', but doesn't state what happens to existing pixels on the target side or whether the operation is reversible. Adds some semantic context but not substantially more than the annotations already convey.

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?

One-line summary followed by a compact Args block; the operation is front-loaded and every line earns its place. Slightly verbose in restating default values that the schema already carries.

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

Completeness3/5

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

For a 6-parameter mutation tool with no output schema, the description covers the operation and the tricky cosmetic parameters well, but omits frame and the two required params (filename, layer) entirely. Adequate but with a visible gap an agent would want filled.

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 only 50% and the schema provides no value semantics for direction/source_side/axis (just types and defaults). The description supplies the missing meaning: 'horizontal' = left<->right, 'vertical' = top<->bottom, 'first' = left/top, 'second' = right/bottom, and axis = mirror line position. That is real added value over the schema, though filename and layer are undocumented.

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 ('Mirror one half of a layer onto the other') plus the goal (build symmetric artwork), which is clearly distinct from flip_sprite (whole-sprite flip) and draw_symmetric_pixels (pixel drawing). However it never names an alternative explicitly to route the agent, 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 Guidelines2/5

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

There is no explicit when-to-use guidance, no when-not-to-use, and no reference to siblings like flip_sprite or draw_symmetric_pixels. The parenthetical '(build symmetric artwork)' is the only hint of intent, leaving selection to inference.

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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