Skybox panorama skill for AI agents

skybox-panorama is a skill from the Summer skill library: a guide your AI agent reads when the task matches, so it builds the good version on the first try. Generate a 360-degree sky panorama and wire it as a PanoramaSkyMaterial Sky resource on WorldEnvironment.


Status	Stable
Domains	2D art, Asset pipeline
Version	`1.0.3`
Engine version	`>=4.6`
Recommended set	No, installed by `--all` or by name

When your agent uses it

Generating a 360-degree panoramic sky image for use as a Sky resource (PanoramaSkyMaterial) in a 3D scene
A 3D scene has a flat or default sky and needs a 360-degree backdrop matching the art direction

Install

summer setup installs every skill for your agent. To add only this one:

npx -y summer-engine@latest skills install skybox-panorama --agent claude-code

Swap claude-code for your agent, such as codex or cursor. See Skills for every option.

The skill

This skill generates a single equirectangular panoramic image (2:1 aspect, e.g. 2048×1024 or 4096×2048) suitable for Summer Engine’s PanoramaSkyMaterial. It wires the image into a Sky resource on a WorldEnvironment node so the sky is visible from every camera angle. The most common failure is non-equirectangular output. Image models default to flat scenes. Without an explicit “equirectangular projection”, the result looks fine as a thumbnail but distorts when wrapped onto a sphere: the horizon bows, the zenith pinches, and the sun smears. The prompt suffix and import settings below give a usable sky in one or two tries.

When to use

“Generate a fantasy sky for the level.”
“I need a sci-fi nebula skybox.”
“Make a sunset panorama for the desert scene.”
“Stormy night sky for the haunted level.”
The 3D scene needs a visible sky (not just a flat color background).

When NOT to use

The user wants a 2D parallax background → that’s a separate Sprite2D job, not a panorama.
The user wants a HDRI for environment lighting (not just visual sky) → AI panoramas are LDR by default. For real IBL/HDR, use Polyhaven HDRIs (free CC0). Mention this to the user if lighting realism matters.
The user wants a 3D-modeled sky-dome with geometry (clouds-as-meshes) → out of scope; use a Sphere mesh + custom shader.
The scene is 2D → no sky needed.

Steps

1. Search for an existing sky

assets.search({ query: "<vibe> sky panorama", assetType: "2d_image", scope: "all" })

Polyhaven (polyhaven.com/hdris) hosts hundreds of free CC0 HDRIs. They look more realistic than generated skies and carry real HDR lighting data. Prefer Polyhaven for realistic exteriors; generate for stylized, fantasy or sci-fi skies.

2. Build the prompt — sky description + equirectangular suffix

Pattern:

<sky description>, 360 degree panoramic equirectangular projection, seamless horizontal wrap, no visible seam at left and right edges, distortion-correct for sphere mapping, no foreground objects, no ground horizon line, sky and clouds and atmosphere only

Load-bearing phrases:

360 degree panoramic equirectangular projection — primes the model for the right format.
seamless horizontal wrap, no visible seam at left and right edges — the left and right edges of the image meet when wrapped. If they don’t match, you see a vertical seam in the sky.
no foreground objects, no ground horizon line — skies show only sky. If you include a horizon, it warps weirdly when sphere-mapped and kills the illusion that the sky is at infinite distance.
distortion-correct for sphere mapping — reminds the model that the top/bottom of the image map to the zenith/nadir.

3. Generate, then fix the aspect yourself

Equirectangular MUST be 2:1 (width = 2× height). assets.generate_image has no 2:1 aspectRatio: the closest are 16:9 and 21:9. Generate at 16:9. For a larger sky, leave model out and add width: 2048, height: 1152: a model that reaches that size is picked.

assets.generate_image({
  prompt: "dramatic fantasy sky, golden hour, large purple-orange clouds, distant mountains silhouetted at very bottom, soft god-rays, 360 degree panoramic equirectangular projection, wide panoramic framing, seamless horizontal wrap, no visible seam, no foreground objects, sky only. No vertical seam, no ground objects, no horizon-level detail, not distorted or warped, no characters, no buildings.",
  model: "nano-banana-2",
  style: "realistic",
  aspectRatio: "16:9"
})

The result reports its real width and height. Then one of these has to happen before the image is usable as a panorama:

Crop the 16:9 result to 2:1 by trimming the top and bottom (about 11% of the height) before importing. The width stays whole, so the horizontal wrap the prompt asked for survives; the zenith and nadir are the least informative regions of a sky anyway.
Or generate in the Summer dashboard, which offers 2:1, and bring the result back with summer_import_from_url.
Or use a Polyhaven HDRI, already 2:1 and better for realistic exteriors.

Do not import a 16:9 or 1:1 image as a PanoramaSkyMaterial panorama and call it done — it wraps with obvious horizontal compression. Never crop the sides: that breaks the seamless wrap.

4. Verify the seam and projection

Before wiring, inspect:

Left edge ↔ right edge: mentally place them side-by-side. They should match continuously. If there’s a cloud cut in half on the left and a different cloud on the right, regenerate with stronger emphasis on seamless horizontal wrap.
Top stretching: the top 10% of the image stretches enormously when mapped to the zenith. If there are tight features (a sun, a cloud edge) high up, they’ll smear. Generations with diffuse, soft top regions wrap better than crisp ones.
Bottom: same applies to the nadir. Most skies don’t show much bottom anyway since the camera sits below the horizon — but avoid generating tight features at the very bottom.

If the image fails seam check, regenerate. Some models support seed for variation while keeping prompt — bump the seed.

5. Import to project

summer_import_from_url(url="<fileUrl>", path="res://art/sky/fantasy_sunset.png")

In the import dock:

Repeat: Disabled (panoramas don’t tile — they wrap once via the material).
Filter: Linear with mipmaps (smoother as the camera turns).
Mipmaps: Enabled.
Compress: VRAM Compressed for ship.

6. Wire into WorldEnvironment

summer_set_resource_property reaches exactly one level into a resource — it takes scenePath, nodePath, resourceProperty, subProperty, value, and there is no "a:b:c" colon-path form for walking Environment → Sky → SkyMaterial. Write the Environment (with its Sky and PanoramaSkyMaterial as sub-resources) as a .tres, then attach it in one property set:

summer_write_file(
  path="res://environments/fantasy_sunset.tres",
  content="<Environment .tres: background_mode = 2 (BG_SKY), sky = Sky with a PanoramaSkyMaterial whose panorama is res://art/sky/fantasy_sunset.png, ambient_light_source = 3 (AMBIENT_SOURCE_SKY) if you want IBL>",
  create_only=true
)

summer_add_node(scenePath="res://main.tscn", parent=".", type="WorldEnvironment", name="WorldEnvironment")
summer_set_prop(scenePath="res://main.tscn", path="./WorldEnvironment", key="environment", value="res://environments/fantasy_sunset.tres")
summer_save_scene(scenePath="res://main.tscn")

Every scene-mutating tool takes an explicit scenePath; node paths are relative to that scene’s root (./), not absolute /root/... runtime paths. Note: AI-generated panoramas are LDR (8-bit per channel). For physically-correct IBL with bright suns, the lighting is muted compared to true HDRI. Mention this to the user if they expect strong IBL.

7. Verify in scene

summer_inspect_node(path="WorldEnvironment")

Then summer_play and look around. Sun in the right place? Seam invisible? Top/bottom okay?

Prompt patterns

Goal	Prompt that works	Why
Fantasy sunset	`dramatic fantasy sky at golden hour, large purple and orange clouds, soft god-rays, distant mountain silhouettes at very bottom only, 360 degree panoramic equirectangular projection, seamless horizontal wrap, no visible seam, no foreground, sky only`	Soft top, distant horizon = clean wrap
Sci-fi space nebula	`vast space nebula, deep blue and magenta gas clouds, scattered bright stars, distant galaxy disc, 360 degree panoramic equirectangular projection, seamless horizontal wrap, no visible seam, no foreground objects, no ground`	Space skies wrap easily; no horizon issues
Stormy night	`dark stormy night sky, heavy rolling clouds, distant lightning flashes, full moon partly obscured, 360 degree panoramic equirectangular, seamless wrap, no foreground`	Diffuse cloud structure tolerates wrapping well
Clear blue day	`bright clear blue sky with scattered cumulus clouds, midday sun upper left, 360 degree panoramic equirectangular projection, seamless horizontal wrap, no visible seam, no ground`	Tight sun feature warps; place sun off-center
Alien planet sky	`alien planet sky, two suns one large red one small white, swirling green-purple atmosphere, distant ringed planet at horizon, 360 panoramic equirectangular, seamless wrap, no foreground`	Multi-sun setups wrap if features stay diffuse
Underwater (caustic dome)	`underwater scene seen from below, sun rays piercing water surface, deep blue gradient downward to black, 360 panoramic equirectangular, seamless wrap`	Treat ocean surface as the “sky”; works for underwater levels
Stylized painterly sky	`Studio Ghibli painterly sky, soft cumulus clouds at sunset, warm pastel palette, 360 panoramic equirectangular, seamless wrap, no foreground` (style: “none”)	Style preset would fight painterly

Bad prompts (and why)

Bad	Failure mode
`beautiful sky`	No equirectangular suffix. Returns flat 16:9 photograph. Wrap looks broken.
`sky with mountains and trees and a castle`	Foreground objects. Horizon-level details warp catastrophically when sphere-mapped.
`360 sky` (without 2:1 aspect)	Aspect mismatch. Wrap is misaligned.
`panoramic sky in 4k`	”4k” implies 3840×2160 (16:9), not 2:1. Specify aspect.
`sky with the sun in the center top`	Sun at zenith stretches into a smear. Place sun off-axis.

Anti-patterns

Including foreground or horizon. Mountains, trees, buildings at horizon level warp weirdly when sphere-mapped (the “swimming horizon” effect). Skies show ONLY sky. If the level needs distant mountains, model them as low-poly meshes in the scene, not in the sky texture.
Assuming the image is 2:1. aspectRatio has no 2:1 value; read the returned width and height. A 1:1 or 16:9 panorama wrapped equirectangular has obvious horizontal compression. Crop the top and bottom, or generate in the dashboard where 2:1 exists.
Tight features at zenith/nadir. Anything in the top or bottom 10% of the image gets pinched. Bias toward soft, diffuse features there.
Expecting HDR / IBL quality. AI panoramas are 8-bit. If the user needs realistic environment lighting from the sky, point them at Polyhaven HDRIs (CC0). AI is for visual sky, not for lighting.
Forgetting Repeat: Disabled on import. Panoramas wrap once via the material; if Repeat is on, you can get duplicate-tile artifacts at the seam.

Edge cases

Animated sky (clouds drift). AI gives one frame. Animate via shader (UV scroll on the panorama texture) or layer two panoramas with ProceduralSkyMaterial for the base + a transparent cloud layer.
Day/night cycle. Generate two panoramas (day + night). Cross-fade the sky_material via shader blend or by swapping panorama over a tween. Two LDR panoramas + a blend = serviceable cycle.
First-person VR. AI panoramas at 2048×1024 are too low-res for VR (visible pixels). Generate at 4096×2048 if the model supports it; otherwise use Polyhaven HDRIs at 8K.
Indoor scene. Skyboxes are wasted indoors — use BG_COLOR or a flat black background. Don’t generate a sky for a windowless dungeon.
Visible vertical seam after generation. Fix in Photoshop/GIMP: Filter → Other → Offset by 50% horizontally → the seam moves to the center → heal with content-aware fill or clone stamp → offset back to 0. Or regenerate with seed bump and seamless horizontal wrap, no visible seam at left and right edges repeated twice in the prompt.

Without Summer Engine

In a session without Summer Engine tools (the assets profile; the summer-assets skill has the whole loop), do steps 1-4 and skip steps 5-7 (import, WorldEnvironment, scene check). Pass out with the person’s folder so the image lands there (the summer-assets skill says how). Tell them it is a 2:1 equirectangular panorama, the shape most engines take for a sky.

Fallback (no MCP)

Print the call:

assets.generate_image({
  prompt: "<sky> 360 degree panoramic equirectangular projection, seamless horizontal wrap, no visible seam, no foreground objects, sky only",
  model: "nano-banana-2",
  style: "realistic",
  aspectRatio: "16:9"
})

The dashboard is the better surface for this skill: it offers 2:1 and a real negative prompt, which the asset operations do not. Tell the user to set 2:1 and a negative of vertical seam, foreground, distorted, warped, characters, buildings, then summer_import_from_url to res://art/sky/<name>.png, set Repeat: Disabled, and wire the WorldEnvironment. If MCP is offline entirely: Polyhaven (polyhaven.com/hdris) has hundreds of free CC0 HDRIs ready to drop into PanoramaSkyMaterial, and often the better choice for realistic exteriors.

Handoff

After the sky is wired:

Add atmospheric fog matching the sky’s mood → scene-composition (fog is on the same Environment resource).
Add a directional DirectionalLight3D matching the sun position in the panorama → 3d-lighting for sun + shadows.
Day/night cycle → re-invoke this skill for the night sky, then write a small tween between the two panorama properties.
Tileable ground texture for the level floor → tileable-texture.

From a shell

No Summer MCP tools in this session? Run each one as a command; when summer --version is missing or below 4.0, use npx -y summer-engine@latest in place of summer. Fields are flags in kebab-case (--scene-path res://main.tscn) or one --input '<json>', and summer ops describe <op> prints the exact input. The summer-cli skill has the rest.

In this skill	Command
`assets.generate_image`, `summer_assets_generate_image`	`summer assets generate-image`
`summer_assets_search`	`summer assets search`
`summer_docs_read`	`summer docs read`
`summer_add_node`	`summer engine add-node`
`summer_import_from_url`	`summer engine import-from-url`
`summer_inspect_node`	`summer engine inspect-node`
`summer_play`	`summer engine play`
`summer_save_scene`	`summer engine save-scene`
`summer_set_prop`	`summer engine set-prop`
`summer_set_resource_property`	`summer engine set-resource-property`
`summer_write_file`	`summer engine write-file`

tileable-texture: Generate a seamless tileable texture for walls, floors or terrain, wired as a StandardMaterial3D albedo.
asset-strategy: Route any ‘I need a [thing]’ asset request to the right skill: 2D, 3D, audio, video, VFX or animation.

Source: library/skills/skybox-panorama/SKILL.md, rendered from summer-engine@4.3.0 on npm.

​When your agent uses it

​Install

​The skill

​When to use

​When NOT to use

​Steps

​1. Search for an existing sky

​2. Build the prompt — sky description + equirectangular suffix

​3. Generate, then fix the aspect yourself

​4. Verify the seam and projection

​5. Import to project

​6. Wire into WorldEnvironment

​7. Verify in scene

​Prompt patterns

​Bad prompts (and why)

​Anti-patterns

​Edge cases

​Without Summer Engine

​Fallback (no MCP)

​Handoff

​See also

​From a shell

​Related skills