develop is the trunk; main holds released code and moves by fast-forward at a release

CI runs on merges to develop (and on fork pull requests); the release workflow builds the draft
from a push to main. AGENTS.md, CONTRIBUTING.md and docs/releasing.md follow.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

.github/workflows/ci.yml

@@ -1,7 +1,8 @@
 name: CI
 
-# CI runs once per merge, on main (AGENTS.md, "Workflow for every change"): the core team's pull
+# CI runs once per merge on `develop`, the trunk (AGENTS.md, "Workflow for every change"): the core
-# requests are checked locally on the crates they touch and merged; a red main is fixed forward.
+# team's pull requests are checked locally on the crates they touch and merged; a red trunk is
+# fixed forward. `main` holds released code only (docs/releasing.md).
 # Pull requests from forks (outside contributors) run the full gate, once the maintainer approves
 # the run, so the review sees it.
 on:
@@ -13,7 +14,7 @@ on:
       - 'docs/features.md'
       - 'docs/oracle.md'
   push:
-    branches: [main]
+    branches: [develop]
     # A merge that only touches prose starts no run. The generated pages are checked by the jobs
     # (features.md by `cargo xtask ci`, oracle.md by the oracle job), so they still count.
     # (Later patterns override earlier ones.)
@@ -24,7 +25,7 @@ on:
       - 'docs/features.md'
       - 'docs/oracle.md'
   schedule:
-    # Nightly: the heavy tests on main.
+    # Nightly, on the default branch (develop): the heavy tests.
     - cron: '23 3 * * *'
   workflow_dispatch:
 
@@ -54,7 +55,7 @@ jobs:
           targets: wasm32-unknown-unknown
       - uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
         with:
-          save-if: ${{ github.ref == 'refs/heads/main' }}
+          save-if: ${{ github.ref == 'refs/heads/develop' }}
       - run: cargo xtask ci
 
   heavy:
@@ -68,7 +69,7 @@ jobs:
       - uses: dtolnay/rust-toolchain@stable
       - uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
         with:
-          save-if: ${{ github.ref == 'refs/heads/main' }}
+          save-if: ${{ github.ref == 'refs/heads/develop' }}
       - run: cargo xtask test --heavy
 
   oracle:
@@ -85,7 +86,7 @@ jobs:
       - uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
         with:
           key: oracle
-          save-if: ${{ github.ref == 'refs/heads/main' }}
+          save-if: ${{ github.ref == 'refs/heads/develop' }}
       - run: cargo xtask oracle
       - name: docs/oracle.md is current
         run: git diff --exit-code docs/oracle.md

.github/workflows/release.yml

@@ -1,11 +1,12 @@
 # Release builds (docs/releasing.md), after SolidCraft's and VectorCraft's release.yml
 # (MIT OR Apache-2.0; see ATTRIBUTION.md).
 #
-# A push to `release` (fast-forwarded from main) builds every package and creates or updates the
+# A push to `main` (fast-forwarded from a verified `develop` commit; main holds released code only)
+# builds every package and creates or updates the
 # DRAFT GitHub Release "FieldCraft v<version>", with SHA256SUMS.txt and generated notes. The
 # version is [workspace.package] version in Cargo.toml; a suffix (0.2.0-rc.1) makes a
 # pre-release. A person verifies the draft and publishes it; this workflow never publishes,
-# and pushes to main or tags never start it.
+# and pushes to develop or tags never start it.
 #
 #   macOS universal (arm64 + x86_64)   .dmg with FieldCraft.app, the CLI as a .zip   packaging/macos
 #   Linux x86_64 (glibc 2.35+)         .tar.gz and .AppImage                          packaging/linux
@@ -15,17 +16,17 @@
 # otherwise (the release notes say which). Linux and Windows builds are not signed.
 #
 # Dry run: `gh workflow run release.yml --ref <branch>` builds everything and uploads the
-# `release-assets` artifact without creating a release. `-f draft=true` on `release` retries
+# `release-assets` artifact without creating a release. `-f draft=true` on `main` retries
 # the draft.
 name: Release
 
 on:
   push:
-    branches: [release]
+    branches: [main]
   workflow_dispatch:
     inputs:
       draft:
-        description: "Create/update the draft release (release branch only; off: build artifacts only)"
+        description: "Create/update the draft release (main only; off: build artifacts only)"
         type: boolean
         default: false
 
@@ -60,8 +61,8 @@ jobs:
             echo "::error::Cargo.toml must contain a version like 1.2.3 or 1.2.3-rc.1, not '$VERSION'"
             exit 1
           fi
-          if [ "$REQUEST_DRAFT" = true ] && [ "$GITHUB_REF" != refs/heads/release ]; then
+          if [ "$REQUEST_DRAFT" = true ] && [ "$GITHUB_REF" != refs/heads/main ]; then
-            echo "::error::Draft releases are built from the release branch only"
+            echo "::error::Draft releases are built from main only"
             exit 1
           fi
           case "$VERSION" in *-*) pre=true ;; *) pre=false ;; esac
@@ -86,7 +87,7 @@ jobs:
         with:
           key: release-macos-universal
           # Release runs are rare: only release-branch runs keep a cache, so dry runs don't evict CI's.
-          save-if: ${{ github.ref == 'refs/heads/release' }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: Import the signing certificate (skipped without APPLE_CERTIFICATE)
         env:
           APPLE_CERTIFICATE: ${{ secrets.APPLE_CERTIFICATE }}
@@ -129,7 +130,7 @@ jobs:
         with:
           key: release-linux-x86_64
           # Release runs are rare: only release-branch runs keep a cache, so dry runs don't evict CI's.
-          save-if: ${{ github.ref == 'refs/heads/release' }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: Build and package (tar.gz, AppImage)
         run: packaging/linux/package.sh
       - name: Check the packages
@@ -167,7 +168,7 @@ jobs:
         with:
           key: release-windows-x64
           # Release runs are rare: only release-branch runs keep a cache, so dry runs don't evict CI's.
-          save-if: ${{ github.ref == 'refs/heads/release' }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: Build and package (zip)
         shell: pwsh
         run: ./packaging/windows/package.ps1

AGENTS.md

@@ -99,7 +99,7 @@ People trust FieldCraft with their models; a crash loses their work. **This outr
   1. Work in your own worktree on a branch, with your own `CARGO_TARGET_DIR`. While you work:
      `cargo check` and the tests of the crates you touch (`cargo test -p <crate>`). Commit after
      each working step (a layer that compiles with its tests passing), not one big commit per PR.
-     Every commit lands on `main` as it is, so each one must build and pass its tests and say
+     Every commit lands on `develop` as it is, so each one must build and pass its tests and say
      what it does: `git bisect` walks them one by one.
   2. When the change is done: review it once with `/simplify`, then `cargo fmt --all` and
      `cargo clippy -p <crate> --all-targets -- -D warnings` for each crate you touched, once.
@@ -108,11 +108,12 @@ People trust FieldCraft with their models; a crash loses their work. **This outr
      oracle cases or solver numerics change (`cargo xtask oracle`).
   3. Fold every fix into the commit it fixes, never a separate "fmt", "clippy", "review fixes" or
      "regenerate features.md" commit: `git commit --fixup <sha>`, then
-     `git rebase -i --autosquash origin/main` (`GIT_SEQUENCE_EDITOR=true` keeps it
+     `git rebase -i --autosquash origin/develop` (`GIT_SEQUENCE_EDITOR=true` keeps it
      non-interactive). A regenerated page goes into the commit that changed what it lists.
-  4. Rebase onto the latest `origin/main` (never merge `main` into a branch), rerun the tests of
+  4. Branch from and rebase onto the latest `origin/develop`, the trunk (never merge `develop` into
-     the touched crates, push, open the PR and merge it with a rebase merge, which keeps `main`
+     a branch), rerun the tests of
-     linear and every commit bisectable. `main` is protected (CODEOWNERS review, linear history,
+     the touched crates, push, open the PR and merge it with a rebase merge, which keeps `develop`
+     linear and every commit bisectable. `develop` and `main` are protected (CODEOWNERS review, linear history,
      rebase merges only); the core team merges as the maintainer with
      `gh pr merge <N> --rebase --admin --delete-branch`, run as its own command. Outside
      contributors' pull requests wait for the maintainer's review (CONTRIBUTING.md). Never squash.
@@ -120,20 +121,21 @@ People trust FieldCraft with their models; a crash loses their work. **This outr
   5. Never run the full gate locally: no `cargo xtask ci`, no `cargo clippy --workspace`, no
      `cargo xtask wasm` or `oracle` unless step 2 calls for it. Never watch CI. GitHub CI runs
      `cargo xtask ci` (fmt, assets, licences, layers, clippy -D warnings, tests, wasm), the
-     oracle, the heavy tests and the advisories once per merge on `main`; the coordinator
+     oracle, the heavy tests and the advisories once per merge on `develop`; the coordinator
      watches it and sends a failure back to the change that caused it, which is fixed forward
      at once.
-- **Keep the main gate fast** (under ~3 minutes on CI). A test that takes more than a few seconds
+- **Keep the trunk gate fast** (under ~3 minutes on CI). A test that takes more than a few seconds
   (convergence studies, the whole corpus, cross-checks between solvers) is
   `#[ignore = "heavy: cargo xtask test --heavy (CI heavy job)"]`, with a fast representative
-  test left in the main gate. The `heavy` CI job runs `cargo xtask test --heavy` (every ignored
+  test left in the trunk gate. The `heavy` CI job runs `cargo xtask test --heavy` (every ignored
-  test, benchmarks included, and the doc tests) on every merge to `main`, nightly and on
+  test, benchmarks included, and the doc tests) on every merge to `develop`, nightly and on
   demand (`gh workflow run CI --ref <branch>`). Hostile-input tests run commands on sessions with small
   work caps (`Session::limits`) so refusals are instant; never lower the production caps for a
   test.
 - **Publishing**: `origin` is github.com/jyviko/fieldcraft. Changes land through pull requests
   as the workflow above describes; the coordinator reads every merged diff and sends findings
-  back as fix-forward work. Never force-push `main`. Never commit `plan/`, `.agent-files/`,
+  back as fix-forward work. Never force-push `develop` or `main`; `main` holds released code and moves only by
+  fast-forward at a release (docs/releasing.md). Never commit `plan/`, `.agent-files/`,
   `worktrees/` or `target*/`; check `git ls-files` before pushing.
 
 ## Running

CONTRIBUTING.md

@@ -18,7 +18,8 @@ Issues labelled **in progress** are being worked on by the core team; please don
 
 ## Making the change
 
-1. Branch from `main`, keep a pull request to one topic.
+1. Branch from `develop` (the trunk; `main` holds released code only) and open the pull request
+   against `develop`. Keep it to one topic.
 2. Before pushing: `cargo fmt --all`, and `cargo clippy -p <crate> --all-targets -- -D warnings`
    and `cargo test -p <crate>` for the crates you touched. CI runs the full gate on your pull
    request once the maintainer approves the run.
@@ -30,6 +31,7 @@ Issues labelled **in progress** are being worked on by the core team; please don
 
 By contributing you agree your work is licensed under MIT OR Apache-2.0.
 
-`main` is protected: changes land only through pull requests that the maintainer has reviewed,
+`develop` and `main` are protected: changes land on `develop` only through pull requests that the
+maintainer has reviewed,
 as rebase merges (keep each commit building and passing its tests). Be kind: see the
 [code of conduct](CODE_OF_CONDUCT.md).

docs/releasing.md

@@ -1,9 +1,9 @@
 # Releasing FieldCraft
 
-Releases are deliberate. Development lands on `main`; pushing the chosen commit to the `release`
+Releases are deliberate. Development lands on `develop`, the trunk; `main` holds released code
-branch builds every package and creates a **draft** GitHub Release; a maintainer verifies the
+only. Fast-forwarding `main` to the chosen, verified `develop` commit builds every package and
-draft and publishes it. Pushes to `main` and tags never start a release, and nothing bumps the
+creates a **draft** GitHub Release; a maintainer verifies the draft and publishes it. Pushes to
-version automatically. The workflow is `.github/workflows/release.yml`; the packaging scripts
+`develop` and tags never start a release, and nothing bumps the version automatically. The workflow is `.github/workflows/release.yml`; the packaging scripts
 are in `packaging/` and run the same way on a developer machine.
 
 ## What a release contains
@@ -57,22 +57,21 @@ certificate is added.
    notes); `-rc.N` for a release candidate. `1.0` is the owner's decision.
 2. Set `[workspace.package] version` in the root `Cargo.toml` and run
    `cargo update --workspace --offline`, which changes only the workspace crates' versions in
-   `Cargo.lock`. Land it on `main` through a pull request like any change, and let CI on `main`
+   `Cargo.lock`. Land it on `develop` through a pull request like any change, and let CI on
-   pass. Note the commit to release.
+   `develop` pass. Note the commit to release.
 
 ## Build the draft
 
 ```sh
 git fetch origin
-git switch release                 # the first time: git switch -c release origin/main
+git push origin <commit>:main      # fast-forward main to the verified develop commit
-git merge --ff-only origin/main
-git push origin release
 ```
 
-Only fast-forward `release` and never force-push it. The run builds the three platforms; when
+`main` holds released code only: it moves only by fast-forwarding to a verified `develop`
+commit (a maintainer push; the branch is protected), never by merges, rewrites or force-pushes. The run builds the three platforms; when
 all succeed, the last job checks that every file is there, writes `SHA256SUMS.txt` and the notes,
 and creates the draft `FieldCraft v<version>` targeting the pushed commit. Pushing
-`release` again with the same version rebuilds and replaces the draft's files (its notes are
+`main` again with the same version rebuilds and replaces the draft's files (its notes are
 kept). The job refuses a version whose tag exists or whose release is already published: bump
 the version instead.
 
@@ -98,6 +97,6 @@ Publishing is a maintainer's call; an agent preparing a release stops at the dra
 
 `gh workflow run release.yml -R jyviko/fieldcraft --ref <branch>` builds every package and
 uploads them with the notes as the `release-assets` artifact of the run, without creating a
-release. `-f draft=true` creates or updates the draft, and is accepted on `release` only.
+release. `-f draft=true` creates or updates the draft, and is accepted on `main` only.
 Locally, `packaging/macos/package.sh --arch aarch64` (or `x86_64`, `universal`) and
 `packaging/linux/package.sh` write to `dist/release/`.