diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..3dba941
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,20 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  e2e:
+    runs-on: ubuntu-24.04
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v5
+      - uses: jdx/mise-action@v4
+        with:
+          install: false
+      - run: test/e2e.sh
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..605be18
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 chunkzero
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..1529826
--- /dev/null
+++ b/README.md
@@ -0,0 +1,35 @@
+# mise-chunkzero
+
+A [mise](https://mise.jdx.dev) backend plugin for chunkzero tools. It installs releases listed in
+[chunkzero/mise-registry](https://github.com/chunkzero/mise-registry), verifies each archive's sha256, and keeps the
+runtime files bundled next to the executable.
+
+```toml
+[plugins]
+chunkzero = "https://github.com/chunkzero/mise-chunkzero"
+
+[tools]
+# The newest nightly; `chunkzero:rpp-beta` follows the newest alpha, beta or rc instead.
+"chunkzero:chunk-nightly" = { version = "latest", prerelease = true }
+# An exact version from any channel.
+"chunkzero:rpp" = "0.1.0-nightly.20261004062300.ge282f11816cd"
+```
+
+Each channel is its own tool, so its releases are cached and installed separately from the others. `prerelease = true`
+lets `latest` select nightly and beta versions. With `mise.lock`, the resolved version stays pinned; `mise upgrade`
+moves to the channel's newest release. The registry has no release dates, so mise's `minimum_release_age` doesn't apply
+to these tools.
+
+Stable releases don't need the plugin:
+
+```toml
+[tools]
+"github:chunkzero/chunk" = "latest"
+```
+
+Tools: `chunk`, `rpp`. Platforms: Linux and macOS on x64 and arm64, Windows on x64.
+
+## Development
+
+`test/e2e.sh` installs chunk from a local copy of the registry and checks that a wrong checksum is rejected. Set
+`MISE_CHUNKZERO_REGISTRY` to point the plugin at another registry URL.
diff --git a/hooks/backend_exec_env.lua b/hooks/backend_exec_env.lua
new file mode 100644
index 0000000..aa0cbc2
--- /dev/null
+++ b/hooks/backend_exec_env.lua
@@ -0,0 +1,3 @@
+function PLUGIN:BackendExecEnv(ctx)
+    return { env_vars = { { key = "PATH", value = ctx.install_path } } }
+end
diff --git a/hooks/backend_install.lua b/hooks/backend_install.lua
new file mode 100644
index 0000000..e4ef436
--- /dev/null
+++ b/hooks/backend_install.lua
@@ -0,0 +1,54 @@
+local archiver = require("archiver")
+local cmd = require("cmd")
+local file = require("file")
+local http = require("http")
+local registry = require("registry")
+
+local function sha256(path)
+    -- The path goes through the environment, so neither cmd.exe nor sh can expand or split it.
+    local options = { env = { CHUNKZERO_ARCHIVE = path } }
+    local output
+    if RUNTIME.osType == "windows" then
+        -- `(Get-FileHash -Algorithm SHA256 -LiteralPath $env:CHUNKZERO_ARCHIVE).Hash`, encoded so the shell running the command can't expand it.
+        output = cmd.exec("powershell -NoProfile -EncodedCommand KABHAGUAdAAtAEYAaQBsAGUASABhAHMAaAAgAC0AQQBsAGcAbwByAGkAdABoAG0AIABTAEgAQQAyADUANgAgAC0ATABpAHQAZQByAGEAbABQAGEAdABoACAAJABlAG4AdgA6AEMASABVAE4ASwBaAEUAUgBPAF8AQQBSAEMASABJAFYARQApAC4ASABhAHMAaAA=", options)
+    else
+        local command = RUNTIME.osType == "darwin" and "shasum -a 256" or "sha256sum"
+        output = cmd.exec(command .. ' < "$CHUNKZERO_ARCHIVE"', options)
+    end
+    local digest = output:match("^%s*(%x+)")
+    if not digest or #digest ~= 64 then
+        error("couldn't compute the sha256 of " .. path .. ": " .. output)
+    end
+    return digest:lower()
+end
+
+function PLUGIN:BackendInstall(ctx)
+    local tool, channel = registry.parse(ctx.tool)
+    if channel and registry.channel(ctx.version) ~= channel then
+        error(ctx.tool .. " only installs " .. channel .. " versions, not " .. ctx.version)
+    end
+    local entry
+    for _, candidate in ipairs(registry.load(tool).versions) do
+        if candidate.version == ctx.version then
+            entry = candidate
+        end
+    end
+    if not entry then
+        error(tool .. " " .. ctx.version .. " isn't in the chunkzero registry")
+    end
+    local platform = registry.platform()
+    local asset = entry.assets[platform]
+    if not asset or not asset.sha256:match("^%x+$") or #asset.sha256 ~= 64 then
+        error(tool .. " " .. ctx.version .. " has no " .. platform .. " build")
+    end
+
+    local archive = file.join_path(ctx.download_path, tool .. "-" .. ctx.version .. "-" .. platform .. ".tar.gz")
+    http.download_file({ url = asset.url }, archive)
+    local actual = sha256(archive)
+    if actual ~= asset.sha256:lower() then
+        error("checksum mismatch for " .. asset.url .. ": expected " .. asset.sha256 .. ", got " .. actual)
+    end
+    -- Archives hold one top-level directory with the executable and the runtime files it loads relative to itself.
+    archiver.decompress(archive, ctx.install_path, { strip_components = 1 })
+    return {}
+end
diff --git a/hooks/backend_list_versions.lua b/hooks/backend_list_versions.lua
new file mode 100644
index 0000000..09a7389
--- /dev/null
+++ b/hooks/backend_list_versions.lua
@@ -0,0 +1,14 @@
+local registry = require("registry")
+
+-- `chunkzero:chunk-nightly` and `chunkzero:chunk-beta` list only that channel's releases, so mise's `latest` picks its
+-- newest; as separate tools they also get separate caches and installs. `chunkzero:chunk` lists every release.
+function PLUGIN:BackendListVersions(ctx)
+    local tool, channel = registry.parse(ctx.tool)
+    local versions = {}
+    for _, entry in ipairs(registry.load(tool).versions) do
+        if channel == nil or registry.channel(entry.version) == channel then
+            table.insert(versions, entry.version)
+        end
+    end
+    return { versions = versions }
+end
diff --git a/lib/registry.lua b/lib/registry.lua
new file mode 100644
index 0000000..d9a06c5
--- /dev/null
+++ b/lib/registry.lua
@@ -0,0 +1,74 @@
+local http = require("http")
+local json = require("json")
+
+local M = {}
+
+-- MISE_CHUNKZERO_REGISTRY overrides the registry base URL, e.g. to test against a local copy.
+M.BASE = os.getenv("MISE_CHUNKZERO_REGISTRY") or "https://raw.githubusercontent.com/chunkzero/mise-registry/main"
+
+local CHANNELS = { nightly = true, beta = true }
+
+--- Splits `chunk-nightly` into ("chunk", "nightly"); a bare `chunk` lists every channel.
+function M.parse(name)
+    if not name:match("^%l[%l%d%-]*$") then
+        error("invalid chunkzero tool name " .. name)
+    end
+    local tool, channel = name:match("^(.-)%-(%l+)$")
+    if tool and CHANNELS[channel] then
+        return tool, channel
+    end
+    return name, nil
+end
+
+function M.channel(version)
+    if version:find("-nightly.", 1, true) then
+        return "nightly"
+    end
+    return version:find("-", 1, true) and "beta" or "latest"
+end
+
+local VERSIONS = {
+    "^%d+%.%d+%.%d+$",
+    "^%d+%.%d+%.%d+%-alpha%.%d+$",
+    "^%d+%.%d+%.%d+%-beta%.%d+$",
+    "^%d+%.%d+%.%d+%-rc%.%d+$",
+    "^%d+%.%d+%.%d+%-nightly%.%d+%.g%x+$",
+}
+
+function M.valid_version(version)
+    for _, pattern in ipairs(VERSIONS) do
+        if version:match(pattern) then
+            return true
+        end
+    end
+    return false
+end
+
+function M.load(tool)
+    local response = http.get({ url = M.BASE .. "/tools/" .. tool .. ".json" })
+    if response.status_code == 404 then
+        error("chunkzero has no tool named " .. tool .. "; see https://github.com/chunkzero/mise-registry/tree/main/tools")
+    end
+    if response.status_code ~= 200 then
+        error("couldn't read the chunkzero registry for " .. tool .. ": HTTP " .. response.status_code)
+    end
+    local registry = json.decode(response.body)
+    for _, entry in ipairs(registry.versions) do
+        if not M.valid_version(entry.version) then
+            error("the chunkzero registry lists an invalid " .. tool .. " version: " .. entry.version)
+        end
+    end
+    return registry
+end
+
+function M.platform()
+    local os_names = { linux = "linux", darwin = "darwin", windows = "windows" }
+    local arch_names = { amd64 = "x64", arm64 = "arm64" }
+    local os_name, arch = os_names[RUNTIME.osType], arch_names[RUNTIME.archType]
+    if not os_name or not arch then
+        error("chunkzero tools don't support " .. RUNTIME.osType .. "-" .. RUNTIME.archType)
+    end
+    return os_name .. "-" .. arch
+end
+
+return M
diff --git a/metadata.lua b/metadata.lua
new file mode 100644
index 0000000..bdd3afe
--- /dev/null
+++ b/metadata.lua
@@ -0,0 +1,8 @@
+PLUGIN = {}
+PLUGIN.name = "chunkzero"
+PLUGIN.version = "0.1.0"
+PLUGIN.homepage = "https://github.com/chunkzero/mise-chunkzero"
+PLUGIN.license = "MIT"
+PLUGIN.description = "Installs chunkzero tools (chunk, rpp) from chunkzero/mise-registry"
+PLUGIN.minRuntimeVersion = "0.3.0"
+PLUGIN.notes = {}
diff --git a/test/e2e.sh b/test/e2e.sh
new file mode 100755
index 0000000..15ea038
--- /dev/null
+++ b/test/e2e.sh
@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+# Installs chunk through the plugin from a local registry copy, then checks that other channels' versions and wrong checksums are rejected.
+set -euo pipefail
+root=$(cd "$(dirname "$0")/.." && pwd)
+work=$(mktemp -d)
+trap 'kill "$server" 2>/dev/null; rm -rf "$work"' EXIT
+cp -r "$root/test/registry" "$work/registry"
+python3 -m http.server 8765 --bind 127.0.0.1 --directory "$work/registry" >/dev/null 2>&1 &
+server=$!
+sleep 1
+
+export MISE_DATA_DIR="$work/data" MISE_CACHE_DIR="$work/cache" MISE_STATE_DIR="$work/state" MISE_CONFIG_DIR="$work/config"
+export MISE_GLOBAL_CONFIG_FILE="$work/config/config.toml" MISE_YES=1 MISE_CHUNKZERO_REGISTRY=http://127.0.0.1:8765
+mkdir -p "$work/project" && cd "$work/project"
+mise plugins link chunkzero "$root"
+cat > mise.toml <<'TOML'
+[tools]
+"chunkzero:chunk-nightly" = { version = "latest", prerelease = true }
+TOML
+mise trust -q
+mise install
+mise exec -- chunk --version | grep -qx 'chunk 0.1.0-nightly.20261004.ge282f11816cd'
+if mise install chunkzero:chunk-beta@0.1.0-nightly.20261004.ge282f11816cd 2>"$work/error"; then
+  echo "installed a nightly as a beta" >&2
+  exit 1
+fi
+grep -q "only installs beta versions" "$work/error"
+
+sed -i 's/"sha256": "[0-9a-f]*"/"sha256": "'"$(printf '0%.0s' {1..64})"'"/' "$work/registry/tools/chunk.json"
+rm -rf "$MISE_DATA_DIR/installs" "$MISE_CACHE_DIR"
+if mise install 2>"$work/error"; then
+  echo "installed despite a wrong checksum" >&2
+  exit 1
+fi
+grep -q "checksum mismatch" "$work/error"
+echo "ok"
diff --git a/test/registry/tools/chunk.json b/test/registry/tools/chunk.json
new file mode 100644
index 0000000..185447e
--- /dev/null
+++ b/test/registry/tools/chunk.json
@@ -0,0 +1,16 @@
+{
+  "repository": "chunkzero/chunk",
+  "channels": { "nightly": "0.1.0-nightly.20261004.ge282f11816cd" },
+  "versions": [
+    {
+      "version": "0.1.0-nightly.20261004.ge282f11816cd",
+      "tag": "v0.1.0-nightly.20261004.ge282f11816cd",
+      "assets": {
+        "linux-x64": {
+          "url": "https://github.com/chunkzero/chunk/releases/download/v0.1.0-nightly.20261004.ge282f11816cd/chunk-0.1.0-nightly.20261004.ge282f11816cd-linux-x64.tar.gz",
+          "sha256": "e707dc45481899d3d49b759695c602e000a828089fea9430d23abf5225bdc96a"
+        }
+      }
+    }
+  ]
+}