From a2943b0c70fe212a1af3945cfb1869f02985e7cd Mon Sep 17 00:00:00 2001
From: Lawrence Chen <54008264+lawrencecchen@users.noreply.github.com>
Date: Sat, 14 Feb 2026 02:43:03 -0800
Subject: [PATCH] Add nightly update channel workflow and adopt AGPL licensing

---
 .github/workflows/nightly.yml                 | 300 ++++++++
 CONTRIBUTING.md                               |   4 +
 .../CmuxWebViewKeyEquivalentTests.swift       |  53 ++
 LICENSE                                       | 661 ++++++++++++++++++
 PROJECTS.md                                   |   2 +
 README.md                                     |   6 +
 Sources/Update/UpdateController.swift         |   1 +
 Sources/Update/UpdateDelegate.swift           |  28 +-
 docs-site/content/docs/configuration.mdx      |   7 +
 docs-site/package.json                        |   1 +
 package.json                                  |   5 +-
 web/package.json                              |   1 +
 12 files changed, 1063 insertions(+), 6 deletions(-)
 create mode 100644 .github/workflows/nightly.yml
 create mode 100644 LICENSE

diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
new file mode 100644
index 00000000..492c5dc6
--- /dev/null
+++ b/.github/workflows/nightly.yml
@@ -0,0 +1,300 @@
+name: Nightly macOS build
+
+on:
+  schedule:
+    # 09:30 UTC daily
+    - cron: "30 9 * * *"
+  workflow_dispatch:
+    inputs:
+      force:
+        description: Force a nightly build even if main has no new commits
+        required: false
+        default: false
+        type: boolean
+
+permissions:
+  contents: write
+
+jobs:
+  decide:
+    runs-on: ubuntu-latest
+    outputs:
+      should_build: ${{ steps.decide.outputs.should_build }}
+      head_sha: ${{ steps.decide.outputs.head_sha }}
+      short_sha: ${{ steps.decide.outputs.short_sha }}
+    steps:
+      - name: Decide whether a nightly build is needed
+        id: decide
+        uses: actions/github-script@v7
+        env:
+          FORCE_BUILD: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.force == 'true' && 'true' || 'false' }}
+        with:
+          script: |
+            const forceBuild = process.env.FORCE_BUILD === 'true';
+            const { owner, repo } = context.repo;
+
+            const branch = await github.rest.repos.getBranch({
+              owner,
+              repo,
+              branch: 'main',
+            });
+            const headSha = branch.data.commit.sha;
+
+            let nightlySha = null;
+            try {
+              const ref = await github.rest.git.getRef({
+                owner,
+                repo,
+                ref: 'tags/nightly',
+              });
+              if (ref.data.object.type === 'commit') {
+                nightlySha = ref.data.object.sha;
+              } else if (ref.data.object.type === 'tag') {
+                const tagObject = await github.rest.git.getTag({
+                  owner,
+                  repo,
+                  tag_sha: ref.data.object.sha,
+                });
+                nightlySha = tagObject.data.object.sha;
+              }
+            } catch (error) {
+              if (error.status !== 404) throw error;
+            }
+
+            const shouldBuild = forceBuild || nightlySha !== headSha;
+            core.setOutput('should_build', shouldBuild ? 'true' : 'false');
+            core.setOutput('head_sha', headSha);
+            core.setOutput('short_sha', headSha.slice(0, 7));
+            core.summary
+              .addHeading('Nightly build decision')
+              .addTable([
+                [{data: 'main HEAD', header: true}, headSha],
+                [{data: 'nightly tag', header: true}, nightlySha ?? '(missing)'],
+                [{data: 'force build', header: true}, String(forceBuild)],
+                [{data: 'should build', header: true}, String(shouldBuild)],
+              ])
+              .write();
+
+  build-sign-notarize-nightly:
+    needs: decide
+    if: needs.decide.outputs.should_build == 'true'
+    runs-on: self-hosted
+    concurrency:
+      group: self-hosted-build
+      cancel-in-progress: false
+    steps:
+      - name: Checkout main
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ needs.decide.outputs.head_sha }}
+          submodules: recursive
+
+      - name: Select Xcode
+        run: |
+          set -euo pipefail
+          if [ -d "/Applications/Xcode.app/Contents/Developer" ]; then
+            XCODE_DIR="/Applications/Xcode.app/Contents/Developer"
+          else
+            XCODE_APP="$(ls -d /Applications/Xcode*.app 2>/dev/null | head -n 1 || true)"
+            if [ -n "$XCODE_APP" ]; then
+              XCODE_DIR="$XCODE_APP/Contents/Developer"
+            else
+              echo "No Xcode.app found under /Applications" >&2
+              exit 1
+            fi
+          fi
+          echo "DEVELOPER_DIR=$XCODE_DIR" >> "$GITHUB_ENV"
+          export DEVELOPER_DIR="$XCODE_DIR"
+          xcodebuild -version
+          xcrun --sdk macosx --show-sdk-path
+
+      - name: Install build deps
+        run: |
+          brew update
+          brew install zig
+          npm install --global create-dmg
+
+      - name: Build GhosttyKit.xcframework
+        run: |
+          cd ghostty
+          zig build -Demit-xcframework=true -Demit-macos-app=false -Dxcframework-target=native -Doptimize=ReleaseFast
+          cd ..
+          rm -rf GhosttyKit.xcframework
+          cp -R ghostty/macos/GhosttyKit.xcframework GhosttyKit.xcframework
+
+      - name: Clear SPM cache
+        run: |
+          rm -rf ~/Library/Caches/org.swift.swiftpm
+          rm -rf ~/Library/Developer/Xcode/DerivedData/GhosttyTabs-*
+
+      - name: Configure SwiftPM cache
+        run: |
+          set -euo pipefail
+          CACHE_DIR="${RUNNER_TEMP}/swiftpm-cache/${GITHUB_RUN_ID}"
+          rm -rf "$CACHE_DIR"
+          mkdir -p "$CACHE_DIR"
+          echo "SWIFTPM_CACHE_PATH=$CACHE_DIR" >> "$GITHUB_ENV"
+
+      - name: Derive Sparkle public key from private key
+        env:
+          SPARKLE_PRIVATE_KEY: ${{ secrets.SPARKLE_PRIVATE_KEY }}
+        run: |
+          if [ -z "$SPARKLE_PRIVATE_KEY" ]; then
+            echo "Missing SPARKLE_PRIVATE_KEY secret" >&2
+            exit 1
+          fi
+          DERIVED_PUBLIC_KEY=$(swift scripts/derive_sparkle_public_key.swift "$SPARKLE_PRIVATE_KEY")
+          echo "Derived Sparkle public key: $DERIVED_PUBLIC_KEY"
+          echo "SPARKLE_PUBLIC_KEY=$DERIVED_PUBLIC_KEY" >> "$GITHUB_ENV"
+
+      - name: Build app (Release)
+        run: |
+          xcodebuild -scheme cmux -configuration Release -derivedDataPath build CODE_SIGNING_ALLOWED=NO build
+
+      - name: Inject Sparkle keys and nightly metadata
+        run: |
+          set -euo pipefail
+          APP_PLIST="build/Build/Products/Release/cmux.app/Contents/Info.plist"
+
+          /usr/libexec/PlistBuddy -c "Delete :SUPublicEDKey" "$APP_PLIST" >/dev/null 2>&1 || true
+          /usr/libexec/PlistBuddy -c "Delete :SUFeedURL" "$APP_PLIST" >/dev/null 2>&1 || true
+          /usr/libexec/PlistBuddy -c "Add :SUPublicEDKey string ${SPARKLE_PUBLIC_KEY}" "$APP_PLIST"
+          /usr/libexec/PlistBuddy -c "Add :SUFeedURL string https://github.com/manaflow-ai/cmux/releases/latest/download/appcast.xml" "$APP_PLIST"
+
+          BASE_BUILD=$(/usr/libexec/PlistBuddy -c "Print :CFBundleVersion" "$APP_PLIST")
+          NIGHTLY_DATE=$(date -u +%Y%m%d)
+          NIGHTLY_BUILD="${BASE_BUILD}.${NIGHTLY_DATE}"
+          /usr/libexec/PlistBuddy -c "Set :CFBundleVersion ${NIGHTLY_BUILD}" "$APP_PLIST"
+
+          echo "Nightly build number: ${NIGHTLY_BUILD}"
+          /usr/libexec/PlistBuddy -c "Print :CFBundleShortVersionString" "$APP_PLIST"
+          /usr/libexec/PlistBuddy -c "Print :CFBundleVersion" "$APP_PLIST"
+
+      - name: Import signing cert
+        env:
+          APPLE_CERTIFICATE_BASE64: ${{ secrets.APPLE_CERTIFICATE_BASE64 }}
+          APPLE_CERTIFICATE_PASSWORD: ${{ secrets.APPLE_CERTIFICATE_PASSWORD }}
+        run: |
+          if [ -z "$APPLE_CERTIFICATE_BASE64" ]; then
+            echo "Missing APPLE_CERTIFICATE_BASE64 secret" >&2
+            exit 1
+          fi
+          if [ -z "$APPLE_CERTIFICATE_PASSWORD" ]; then
+            echo "Missing APPLE_CERTIFICATE_PASSWORD secret" >&2
+            exit 1
+          fi
+          KEYCHAIN_PASSWORD="$(uuidgen)"
+          echo "$APPLE_CERTIFICATE_BASE64" | base64 --decode > /tmp/cert.p12
+          security delete-keychain build.keychain >/dev/null 2>&1 || true
+          security create-keychain -p "$KEYCHAIN_PASSWORD" build.keychain
+          security set-keychain-settings -lut 21600 build.keychain
+          security unlock-keychain -p "$KEYCHAIN_PASSWORD" build.keychain
+          security import /tmp/cert.p12 -k build.keychain -P "$APPLE_CERTIFICATE_PASSWORD" -T /usr/bin/codesign -T /usr/bin/security
+          security set-key-partition-list -S apple-tool:,apple: -s -k "$KEYCHAIN_PASSWORD" build.keychain
+          security list-keychains -d user -s build.keychain
+
+      - name: Codesign app
+        env:
+          APPLE_SIGNING_IDENTITY: ${{ secrets.APPLE_SIGNING_IDENTITY }}
+        run: |
+          if [ -z "$APPLE_SIGNING_IDENTITY" ]; then
+            echo "Missing APPLE_SIGNING_IDENTITY secret" >&2
+            exit 1
+          fi
+          APP_PATH="build/Build/Products/Release/cmux.app"
+          CLI_PATH="$APP_PATH/Contents/Resources/bin/cmux"
+          if [ -f "$CLI_PATH" ]; then
+            /usr/bin/codesign --force --options runtime --timestamp --sign "$APPLE_SIGNING_IDENTITY" "$CLI_PATH"
+          fi
+          /usr/bin/codesign --force --options runtime --timestamp --sign "$APPLE_SIGNING_IDENTITY" --deep "$APP_PATH"
+          /usr/bin/codesign --verify --deep --strict --verbose=2 "$APP_PATH"
+
+      - name: Notarize app and dmg
+        env:
+          APPLE_ID: ${{ secrets.APPLE_ID }}
+          APPLE_APP_SPECIFIC_PASSWORD: ${{ secrets.APPLE_APP_SPECIFIC_PASSWORD }}
+          APPLE_TEAM_ID: ${{ secrets.APPLE_TEAM_ID }}
+          APPLE_SIGNING_IDENTITY: ${{ secrets.APPLE_SIGNING_IDENTITY }}
+        run: |
+          if [ -z "$APPLE_ID" ] || [ -z "$APPLE_APP_SPECIFIC_PASSWORD" ] || [ -z "$APPLE_TEAM_ID" ]; then
+            echo "Missing notarization secrets (APPLE_ID, APPLE_APP_SPECIFIC_PASSWORD, APPLE_TEAM_ID)" >&2
+            exit 1
+          fi
+          APP_PATH="build/Build/Products/Release/cmux.app"
+          ZIP_SUBMIT="cmux-nightly-notary.zip"
+          DMG_RELEASE="cmux-macos.dmg"
+          ditto -c -k --sequesterRsrc --keepParent "$APP_PATH" "$ZIP_SUBMIT"
+          APP_SUBMIT_JSON="$(xcrun notarytool submit "$ZIP_SUBMIT" --apple-id "$APPLE_ID" --team-id "$APPLE_TEAM_ID" --password "$APPLE_APP_SPECIFIC_PASSWORD" --wait --output-format json)"
+          APP_SUBMIT_ID="$(python3 -c 'import json,sys; print(json.load(sys.stdin)["id"])' <<<"$APP_SUBMIT_JSON")"
+          APP_STATUS="$(python3 -c 'import json,sys; print(json.load(sys.stdin)["status"])' <<<"$APP_SUBMIT_JSON")"
+          if [ "$APP_STATUS" != "Accepted" ]; then
+            echo "App notarization failed with status: $APP_STATUS" >&2
+            xcrun notarytool log "$APP_SUBMIT_ID" --apple-id "$APPLE_ID" --team-id "$APPLE_TEAM_ID" --password "$APPLE_APP_SPECIFIC_PASSWORD" || true
+            exit 1
+          fi
+          xcrun stapler staple "$APP_PATH"
+          xcrun stapler validate "$APP_PATH"
+          spctl -a -vv --type execute "$APP_PATH"
+          rm -f "$ZIP_SUBMIT"
+          create-dmg \
+            --identity="$APPLE_SIGNING_IDENTITY" \
+            "$APP_PATH" \
+            ./
+          mv ./cmux*.dmg "$DMG_RELEASE"
+          DMG_SUBMIT_JSON="$(xcrun notarytool submit "$DMG_RELEASE" --apple-id "$APPLE_ID" --team-id "$APPLE_TEAM_ID" --password "$APPLE_APP_SPECIFIC_PASSWORD" --wait --output-format json)"
+          DMG_SUBMIT_ID="$(python3 -c 'import json,sys; print(json.load(sys.stdin)["id"])' <<<"$DMG_SUBMIT_JSON")"
+          DMG_STATUS="$(python3 -c 'import json,sys; print(json.load(sys.stdin)["status"])' <<<"$DMG_SUBMIT_JSON")"
+          if [ "$DMG_STATUS" != "Accepted" ]; then
+            echo "DMG notarization failed with status: $DMG_STATUS" >&2
+            xcrun notarytool log "$DMG_SUBMIT_ID" --apple-id "$APPLE_ID" --team-id "$APPLE_TEAM_ID" --password "$APPLE_APP_SPECIFIC_PASSWORD" || true
+            exit 1
+          fi
+          xcrun stapler staple "$DMG_RELEASE"
+          xcrun stapler validate "$DMG_RELEASE"
+
+      - name: Generate Sparkle appcast (nightly)
+        env:
+          SPARKLE_PRIVATE_KEY: ${{ secrets.SPARKLE_PRIVATE_KEY }}
+        run: |
+          if [ -z "$SPARKLE_PRIVATE_KEY" ]; then
+            echo "Missing SPARKLE_PRIVATE_KEY secret" >&2
+            exit 1
+          fi
+          ./scripts/sparkle_generate_appcast.sh cmux-macos.dmg nightly appcast.xml
+
+      - name: Move nightly tag to built commit
+        run: |
+          set -euo pipefail
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+          git tag -f nightly "${{ needs.decide.outputs.head_sha }}"
+          git push origin refs/tags/nightly --force
+
+      - name: Publish nightly release assets
+        uses: softprops/action-gh-release@v2
+        with:
+          tag_name: nightly
+          name: Nightly
+          prerelease: true
+          make_latest: false
+          body: |
+            Automated nightly build for `${{ needs.decide.outputs.short_sha }}`.
+          files: |
+            cmux-macos.dmg
+            appcast.xml
+          overwrite_files: true
+
+      - name: Cleanup keychain
+        if: always()
+        run: |
+          security delete-keychain build.keychain >/dev/null 2>&1 || true
+          rm -f /tmp/cert.p12
+
+  skipped:
+    needs: decide
+    if: needs.decide.outputs.should_build != 'true'
+    runs-on: ubuntu-latest
+    steps:
+      - name: No nightly build needed
+        run: |
+          echo "No changes on main since last nightly tag; skipping build."
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 9e988ad6..b5526dae 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -96,3 +96,7 @@ git commit -m "Update ghostty submodule"
 ```
 
 See `docs/ghostty-fork.md` for details on fork changes and conflict notes.
+
+## License
+
+By contributing to this repository, you agree that your contributions are licensed under the project's GNU Affero General Public License v3.0 or later (`AGPL-3.0-or-later`).
diff --git a/GhosttyTabsTests/CmuxWebViewKeyEquivalentTests.swift b/GhosttyTabsTests/CmuxWebViewKeyEquivalentTests.swift
index 9a38c4e7..4611d234 100644
--- a/GhosttyTabsTests/CmuxWebViewKeyEquivalentTests.swift
+++ b/GhosttyTabsTests/CmuxWebViewKeyEquivalentTests.swift
@@ -250,6 +250,59 @@ final class WorkspacePlacementSettingsTests: XCTestCase {
     }
 }
 
+final class UpdateChannelSettingsTests: XCTestCase {
+    func testDefaultNightlyPreferenceIsDisabled() {
+        XCTAssertFalse(UpdateChannelSettings.defaultIncludeNightlyBuilds)
+    }
+
+    func testResolvedFeedFallsBackToStableWhenInfoFeedMissing() {
+        let suiteName = "UpdateChannelSettingsTests.MissingInfo.\(UUID().uuidString)"
+        guard let defaults = UserDefaults(suiteName: suiteName) else {
+            XCTFail("Failed to create isolated UserDefaults suite")
+            return
+        }
+        defer { defaults.removePersistentDomain(forName: suiteName) }
+
+        let resolved = UpdateChannelSettings.resolvedFeedURLString(infoFeedURL: nil, defaults: defaults)
+        XCTAssertEqual(resolved.url, UpdateChannelSettings.stableFeedURL)
+        XCTAssertFalse(resolved.isNightly)
+        XCTAssertTrue(resolved.usedFallback)
+    }
+
+    func testResolvedFeedUsesInfoFeedForStableChannel() {
+        let suiteName = "UpdateChannelSettingsTests.InfoFeed.\(UUID().uuidString)"
+        guard let defaults = UserDefaults(suiteName: suiteName) else {
+            XCTFail("Failed to create isolated UserDefaults suite")
+            return
+        }
+        defer { defaults.removePersistentDomain(forName: suiteName) }
+
+        let infoFeed = "https://example.com/custom/appcast.xml"
+        let resolved = UpdateChannelSettings.resolvedFeedURLString(infoFeedURL: infoFeed, defaults: defaults)
+        XCTAssertEqual(resolved.url, infoFeed)
+        XCTAssertFalse(resolved.isNightly)
+        XCTAssertFalse(resolved.usedFallback)
+    }
+
+    func testResolvedFeedUsesNightlyWhenPreferenceEnabled() {
+        let suiteName = "UpdateChannelSettingsTests.Nightly.\(UUID().uuidString)"
+        guard let defaults = UserDefaults(suiteName: suiteName) else {
+            XCTFail("Failed to create isolated UserDefaults suite")
+            return
+        }
+        defer { defaults.removePersistentDomain(forName: suiteName) }
+
+        defaults.set(true, forKey: UpdateChannelSettings.includeNightlyBuildsKey)
+        let resolved = UpdateChannelSettings.resolvedFeedURLString(
+            infoFeedURL: "https://example.com/custom/appcast.xml",
+            defaults: defaults
+        )
+        XCTAssertEqual(resolved.url, UpdateChannelSettings.nightlyFeedURL)
+        XCTAssertTrue(resolved.isNightly)
+        XCTAssertFalse(resolved.usedFallback)
+    }
+}
+
 final class WorkspaceReorderTests: XCTestCase {
     @MainActor
     func testReorderWorkspaceMovesWorkspaceToRequestedIndex() {
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 00000000..be3f7b28
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,661 @@
+                    GNU AFFERO GENERAL PUBLIC LICENSE
+                       Version 3, 19 November 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The GNU Affero General Public License is a free, copyleft license for
+software and other kinds of works, specifically designed to ensure
+cooperation with the community in the case of network server software.
+
+  The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works.  By contrast,
+our General Public Licenses are intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+  Developers that use our General Public Licenses protect your rights
+with two steps: (1) assert copyright on the software, and (2) offer
+you this License which gives you legal permission to copy, distribute
+and/or modify the software.
+
+  A secondary benefit of defending all users' freedom is that
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+software used on network servers, this result may fail to come about.
+The GNU General Public License permits making a modified version and
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+
+  The GNU Affero General Public License is designed specifically to
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+
+  An older license, called the Affero General Public License and
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+a different license, not a version of the Affero GPL, but Affero has
+released a new version of the Affero GPL which permits relicensing under
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+
+  The precise terms and conditions for copying, distribution and
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+
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+  "This License" refers to version 3 of the GNU Affero General Public License.
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+or that patent license was granted, prior to 28 March 2007.
+
+  Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+  12. No Surrender of Others' Freedom.
+
+  If conditions are imposed on you (whether by court order, agreement or
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+the Program, the only way you could satisfy both those terms and this
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+
+  13. Remote Network Interaction; Use with the GNU General Public License.
+
+  Notwithstanding any other provision of this License, if you modify the
+Program, your modified version must prominently offer all users
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+following paragraph.
+
+  Notwithstanding any other provision of this License, you have
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+License will continue to apply to the part which is the covered work,
+but the work with which it is combined will remain governed by version
+3 of the GNU General Public License.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU Affero General Public License from time to time.  Such new versions
+will be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU Affero General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
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+Foundation.  If the Program does not specify a version number of the
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+
+  If the Program specifies that a proxy can decide which future
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+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
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+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
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+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
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+  16. Limitation of Liability.
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+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
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+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
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+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
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+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If your software can interact with users remotely through a computer
+network, you should also make sure that it provides a way for users to
+get its source.  For example, if your program is a web application, its
+interface could display a "Source" link that leads users to an archive
+of the code.  There are many ways you could offer source, and different
+solutions will be better for different programs; see section 13 for the
+specific requirements.
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU AGPL, see
+<https://www.gnu.org/licenses/>.
diff --git a/PROJECTS.md b/PROJECTS.md
index 68c08433..6037b3d4 100644
--- a/PROJECTS.md
+++ b/PROJECTS.md
@@ -3,6 +3,8 @@
 Cross-project tracking (features, bugs, backlog) for cmux.
 
 ## Done
+- 2026-02-14: Relicensed the repository to strong copyleft (`AGPL-3.0-or-later`), added canonical `LICENSE` text, and updated project/package metadata to advertise AGPL consistently.
+- 2026-02-14: Added an opt-in nightly update channel in Settings (`Receive nightly builds`) that routes Sparkle feed selection between stable and nightly appcasts, plus a scheduled GitHub Actions nightly pipeline (`.github/workflows/nightly.yml`) that only rebuilds when `main` has new commits since `nightly` (or when manually forced).
 - 2026-02-13: Added `demos/wkwebview-ssh-proxy-cookie-demo/` with a standalone macOS Swift app (two WKWebViews), two Docker backends (`:8080`) running behind separate SSH SOCKS tunnels, and scripts/docs to demonstrate same URL (`shared.test:8080`) routing to different backends plus app-level cookie sync between separate proxy-scoped data stores.
 - 2026-02-13: Expanded skill docs for end users: added deep-linkable `cmux-browser` references (`authentication.md`, `session-management.md`, `snapshot-refs.md`, `video-recording.md`, `proxy-support.md`) + templates, and added a new `skills/cmux/` core skill for windows/workspaces/panes/surfaces workflows.
 - 2026-02-13: Changed CLI ID formatting defaults to refs-first for `--json` output (UUID output now opt-in via `--id-format uuids|both`) and added regression test `tests_v2/test_cli_id_format_defaults.py`.
diff --git a/README.md b/README.md
index 2eec9855..c4b1b9ec 100644
--- a/README.md
+++ b/README.md
@@ -123,3 +123,9 @@ A native macOS app means it launches instantly, uses minimal RAM, and feels righ
 | ⌘ , | Settings |
 | ⌘ ⇧ R | Reload configuration |
 | ⌘ Q | Quit |
+
+## License
+
+This project is licensed under the GNU Affero General Public License v3.0 or later (`AGPL-3.0-or-later`).
+
+See `LICENSE` for the full text.
diff --git a/Sources/Update/UpdateController.swift b/Sources/Update/UpdateController.swift
index 0fc1c4e1..5c53d0cc 100644
--- a/Sources/Update/UpdateController.swift
+++ b/Sources/Update/UpdateController.swift
@@ -31,6 +31,7 @@ class UpdateController {
             "SUEnableAutomaticChecks": false,
             "SUSendProfileInfo": false,
             "SUAutomaticallyUpdate": false,
+            UpdateChannelSettings.includeNightlyBuildsKey: UpdateChannelSettings.defaultIncludeNightlyBuilds,
         ])
 
         let hostBundle = Bundle.main
diff --git a/Sources/Update/UpdateDelegate.swift b/Sources/Update/UpdateDelegate.swift
index 269f3052..38163ec3 100644
--- a/Sources/Update/UpdateDelegate.swift
+++ b/Sources/Update/UpdateDelegate.swift
@@ -1,6 +1,26 @@
 import Sparkle
 import Cocoa
 
+enum UpdateChannelSettings {
+    static let includeNightlyBuildsKey = "cmux.includeNightlyBuilds"
+    static let defaultIncludeNightlyBuilds = false
+
+    static let stableFeedURL = "https://github.com/manaflow-ai/cmux/releases/latest/download/appcast.xml"
+    static let nightlyFeedURL = "https://github.com/manaflow-ai/cmux/releases/download/nightly/appcast.xml"
+
+    static func resolvedFeedURLString(
+        infoFeedURL: String?,
+        defaults: UserDefaults = .standard
+    ) -> (url: String, isNightly: Bool, usedFallback: Bool) {
+        let stableURL = (infoFeedURL?.isEmpty == false) ? infoFeedURL! : stableFeedURL
+        let includeNightlyBuilds = defaults.bool(forKey: includeNightlyBuildsKey)
+        if includeNightlyBuilds {
+            return (url: nightlyFeedURL, isNightly: true, usedFallback: false)
+        }
+        return (url: stableURL, isNightly: false, usedFallback: stableURL == stableFeedURL)
+    }
+}
+
 extension UpdateDriver: SPUUpdaterDelegate {
     func feedURLString(for updater: SPUUpdater) -> String? {
 #if DEBUG
@@ -12,10 +32,10 @@ extension UpdateDriver: SPUUpdaterDelegate {
         }
 #endif
         let infoURL = Bundle.main.object(forInfoDictionaryKey: "SUFeedURL") as? String
-        let fallback = "https://github.com/manaflow-ai/cmux/releases/latest/download/appcast.xml"
-        let feedURLString = (infoURL?.isEmpty == false) ? infoURL! : fallback
-        recordFeedURLString(feedURLString, usedFallback: feedURLString == fallback)
-        return feedURLString
+        let resolved = UpdateChannelSettings.resolvedFeedURLString(infoFeedURL: infoURL)
+        UpdateLogStore.shared.append("update channel: \(resolved.isNightly ? "nightly" : "stable")")
+        recordFeedURLString(resolved.url, usedFallback: resolved.usedFallback)
+        return resolved.url
     }
 
     /// Called when an update is scheduled to install silently,
diff --git a/docs-site/content/docs/configuration.mdx b/docs-site/content/docs/configuration.mdx
index a22bb101..0a2c4f57 100644
--- a/docs-site/content/docs/configuration.mdx
+++ b/docs-site/content/docs/configuration.mdx
@@ -97,6 +97,13 @@ Control socket access level:
   On shared machines, consider using "Notifications only" mode to prevent other processes from controlling your terminals.
 </Callout>
 
+### Update Channel
+
+- **Stable** (default) - Production releases only
+- **Nightly builds** - Opt in to nightly main-branch builds
+
+Nightly builds can include incomplete features or regressions; use them if you want the latest changes quickly.
+
 ## Example Config
 
 Here's a complete example configuration:
diff --git a/docs-site/package.json b/docs-site/package.json
index 894d6e07..8417668e 100644
--- a/docs-site/package.json
+++ b/docs-site/package.json
@@ -1,6 +1,7 @@
 {
   "name": "cmux-docs",
   "version": "0.1.0",
+  "license": "AGPL-3.0-or-later",
   "private": true,
   "scripts": {
     "dev": "next dev",
diff --git a/package.json b/package.json
index 04c6cd2a..7a52b28c 100644
--- a/package.json
+++ b/package.json
@@ -1,5 +1,6 @@
 {
   "dependencies": {
     "vercel": "^50.9.5"
-  }
-}
\ No newline at end of file
+  },
+  "license": "AGPL-3.0-or-later"
+}
diff --git a/web/package.json b/web/package.json
index 3fa347d1..05ca9097 100644
--- a/web/package.json
+++ b/web/package.json
@@ -1,6 +1,7 @@
 {
   "name": "web",
   "version": "0.1.0",
+  "license": "AGPL-3.0-or-later",
   "private": true,
   "scripts": {
     "dev": "next dev --port 3777",