diff --git a/.github/workflows/documentation.yml b/.github/workflows/documentation.yml
index d4245d9..949a97b 100644
--- a/.github/workflows/documentation.yml
+++ b/.github/workflows/documentation.yml
@@ -19,7 +19,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
           persist-credentials: false
       - uses: prefix-dev/setup-pixi@v0.9.3
         with:
@@ -27,7 +27,7 @@ jobs:
           manifest-path: pyproject.toml
           run-install: false
           cache: false
-      - name: Resolve released dependencies once for this workflow
+      - name: Resolve example dependencies once for this workflow
         run: pixi update sequince sequince-density
       - uses: actions/upload-artifact@v4
         with:
@@ -48,7 +48,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
           persist-credentials: false
       - uses: actions/download-artifact@v4
         with:
@@ -81,7 +81,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
           persist-credentials: false
       - uses: actions/download-artifact@v4
         with:
diff --git a/.github/workflows/pr-documentation.yml b/.github/workflows/pr-documentation.yml
new file mode 100644
index 0000000..a40de1d
--- /dev/null
+++ b/.github/workflows/pr-documentation.yml
@@ -0,0 +1,35 @@
+name: Publish PR documentation
+on:
+  workflow_run:
+    workflows: [Example documentation]
+    types: [completed]
+
+permissions:
+  actions: read
+  contents: write
+  pull-requests: read
+
+jobs:
+  publish:
+    if: >-
+      github.repository == 'sequince-dev/sequince-examples' &&
+      github.event.workflow_run.event == 'pull_request' &&
+      github.event.workflow_run.conclusion == 'success'
+    runs-on: ubuntu-latest
+    timeout-minutes: 55
+    concurrency:
+      group: examples-rtd-pr-${{ github.event.workflow_run.head_repository.full_name }}-${{ github.event.workflow_run.head_branch }}
+      cancel-in-progress: false
+    steps:
+      # workflow_run uses trusted default-branch code. Never check out the PR
+      # or execute files from its artifacts in this credential-bearing job.
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ github.sha }}
+          persist-credentials: false
+      - name: Publish bundle and rebuild PR preview
+        run: python3 scripts/publish_pr_docs.py
+        env:
+          GH_TOKEN: ${{ github.token }}
+          RTD_TOKEN: ${{ secrets.RTD_TOKEN }}
+          RTD_PROJECT: ${{ vars.RTD_PROJECT }}
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index f7cd14f..3626cbe 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -43,8 +43,9 @@ Keep local `main` for upstream changes and develop on separate branches. Install
 [Pixi](https://pixi.prefix.dev/latest/installation/), then run:
 
 ```bash
-make -C docs setup
-pixi run --locked -e check pre-commit install
+pixi update sequince sequince-density
+pixi install -e default -e docs -e check
+pixi run -e check pre-commit install
 ```
 
 Dependencies, environments, and tasks are defined in `pyproject.toml`.
@@ -82,15 +83,18 @@ Avoid retaining unnecessary histories or adding expensive diagnostics by default
 Before requesting review, run:
 
 ```bash
-make -C docs check
-make -C docs hooks
+pixi run -e check test
+pixi run -e check lint
+pixi run -e check format-check
+pixi run -e check pre-commit run --all-files
 ```
 
-The first command runs pytest, Ruff linting, and formatting checks. Pre-commit
-also checks spelling, whitespace, YAML, and large files, and may modify files.
-Review any edits and rerun the checks. Do not bypass hooks to make commits pass.
-The configurations in `pyproject.toml` and `.pre-commit-config.yaml` are
-authoritative; this repository does not currently configure mypy.
+These commands run pytest, Ruff linting and formatting checks, and pre-commit.
+Pre-commit also checks spelling, whitespace, YAML, and large files, and may
+modify files. Review any edits and rerun the checks. Do not bypass hooks to make
+commits pass. The configurations in `pyproject.toml` and
+`.pre-commit-config.yaml` are authoritative; this repository does not currently
+configure mypy.
 
 Tests live in `tests/`. Test observable behavior and numerical invariants, using
 small fixed inputs or mocked execution for pipeline tests. Some tests require
@@ -106,30 +110,52 @@ directly in the tutorial, with explanations and the relevant source code. The
 reading order in `docs/index.rst` starts with basic examples, then introduces
 other methods, with flow preconditioning before persistent sampling.
 
-Documentation commands run from the repository root:
+Run documentation commands from the repository root. To generate outputs for
+one example, select its declared environment:
 
 ```bash
-make -C docs help
-make -C docs example EXAMPLE=gaussian
-make -C docs example EXAMPLE=flow-preconditioning ENV=flow
-make -C docs examples
-make -C docs docs
-make -C docs docs-only
-make -C docs validate
+pixi run -e default example gaussian
+pixi run -e flow example flow-preconditioning
 ```
 
-`example` runs one manifest entry; `examples` runs all entries sequentially in
-their declared environments. Each execution batch resolves released dependencies
-once and uses the same lock throughout. `docs` refreshes dependencies, reuses
-valid outputs when possible, and executes examples if outputs are missing or
-stale. `docs-only` validates existing outputs and builds Sphinx HTML without
-sampling. `validate` runs checks, reruns all examples, then builds the docs.
-HTML is written to `docs/_build/html/`.
+To run all registered examples sequentially in their declared environments:
 
-Full example execution can consume substantial memory and time. Choose a single
-example when developing, and use `docs-only` when valid results are available.
-Execution has timeouts, but does not currently enforce a memory limit. Do not
-assume that parallel local execution is safe.
+```bash
+pixi run examples
+```
+
+Each execution batch resolves released dependencies once and uses the same lock
+throughout. Full example execution can consume substantial memory and time;
+choose a single example when developing. Execution has timeouts, but does not
+currently enforce a memory limit. Do not assume parallel local execution is safe.
+
+To validate existing outputs, stage the tutorial pages, and build Sphinx HTML:
+
+```bash
+pixi run -e docs docs
+```
+
+Open `docs/_build/html/index.html` in a browser to review the result. This task
+builds with warnings treated as errors and does not execute sampling. Missing or
+stale outputs cause it to stop; regenerate those outputs before building again.
+Pixi may resolve dependencies and update `pixi.lock` before running a task when
+needed.
+
+The Makefile is a standard Sphinx interface, matching Sequince's documentation.
+It supports builders such as `html`, `linkcheck`, and `clean`; `docs` is an alias
+for `html`. It does not install dependencies, run checks, or execute examples.
+To use Make, stage validated outputs first and run it in the docs environment:
+
+```bash
+pixi run -e docs prepare-docs
+pixi run -e docs make -C docs html SPHINXOPTS="-W --keep-going"
+```
+
+Use `pixi run -e docs make -C docs help` to list Sphinx targets. The Pixi `docs`
+task above performs preparation and the HTML build together.
+
+For full validation, run the checks listed above, then run `pixi run examples`
+and `pixi run -e docs docs`, in that order. Stop if any command fails.
 
 ### Adding an example
 
@@ -161,6 +187,14 @@ installs `docs/requirements.txt`, fetches the exact matching bundle, and verifie
 it before building; it does not run sampling. Freshness checks guard `latest`
 builds, and there is no fallback to results from another commit.
 
+Pull requests run examples and build Sphinx at the PR head commit, matching
+Read the Docs previews. After a successful run, the separate
+`Publish PR documentation` workflow runs trusted code from the default branch.
+It reads the completed run's artifact as data, checks its archive and commit,
+publishes it under `docs-pr-<PR-number>-<head-SHA>`, and requests the PR preview.
+PR code and artifacts are never executed in that publishing job. Read the Docs
+then performs the same output provenance validation used for `latest`.
+
 Maintainers must configure the Read the Docs project, the repository variable
 `RTD_PROJECT`, and the secret `RTD_TOKEN` before enabling this hosting workflow.
 Keep credentials out of source files and pull request jobs. The configuration
diff --git a/docs/Makefile b/docs/Makefile
index 49f98a1..bcd747f 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -1,66 +1,22 @@
-.DEFAULT_GOAL := help
+# Minimal makefile for Sphinx documentation
+#
 
-DOCS_DIR := $(abspath $(dir $(lastword $(MAKEFILE_LIST))))
-REPO_ROOT := $(abspath $(DOCS_DIR)/..)
-
-PIXI ?= pixi
-EXAMPLE ?= gaussian
-ENV ?= default
-
-.PHONY: help setup test lint format-check check hooks example examples refresh docs docs-only validate
+# You can set these variables from the command line, and also
+# from the environment for the first two.
+SPHINXOPTS    ?=
+SPHINXBUILD   ?= sphinx-build
+SOURCEDIR     = .
+BUILDDIR      = _build
 
+# Put it first so that "make" without argument is like "make help".
 help:
-	@printf '%s\n' \
-	  'make setup         Refresh released dependencies and install environments' \
-	  'make refresh       Resolve released dependencies without sampling' \
-	  'make check         Run tests, lint and formatting checks' \
-	  'make test          Run pipeline tests' \
-	  'make lint          Run Ruff lint checks' \
-	  'make format-check  Check Python formatting' \
-	  'make hooks         Run all pre-commit hooks (may edit files)' \
-	  'make example EXAMPLE=gaussian [ENV=default]' \
-	  '                   Run one example in the selected environment' \
-	  'make examples      Run all documentation examples in their environments' \
-	  'make docs          Reuse valid outputs or run examples, then build docs' \
-	  'make docs-only     Build docs using existing validated outputs' \
-	  'make validate      Run checks, all examples, then build docs'
-
-refresh:
-	cd "$(REPO_ROOT)" && $(PIXI) update sequince sequince-density
-
-setup: refresh
-	cd "$(REPO_ROOT)" && $(PIXI) install --locked -e default -e docs -e check
-
-test:
-	cd "$(REPO_ROOT)" && $(PIXI) run --locked -e check test
-
-lint:
-	cd "$(REPO_ROOT)" && $(PIXI) run --locked -e check lint
-
-format-check:
-	cd "$(REPO_ROOT)" && $(PIXI) run --locked -e check format-check
-
-check: test lint format-check
-
-hooks:
-	cd "$(REPO_ROOT)" && $(PIXI) run --locked -e check pre-commit run --all-files
-
-example:
-	cd "$(REPO_ROOT)" && $(PIXI) run --locked -e $(ENV) example $(EXAMPLE)
-
-examples:
-	cd "$(REPO_ROOT)" && $(PIXI) run --locked examples
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
 
-docs: refresh
-	@if ! (cd "$(REPO_ROOT)" && $(PIXI) run --locked -e docs validate-outputs); then \
-	  $(MAKE) -C "$(DOCS_DIR)" examples || exit $$?; \
-	fi
-	$(MAKE) -C "$(DOCS_DIR)" docs-only
+.PHONY: help docs Makefile
 
-docs-only:
-	cd "$(REPO_ROOT)" && $(PIXI) run --locked -e docs docs
+docs: html
 
-# Keep execution before Sphinx even when invoked with make -j.
-validate: check
-	$(MAKE) -C "$(DOCS_DIR)" examples
-	$(MAKE) -C "$(DOCS_DIR)" docs-only
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
diff --git a/docs/index.rst b/docs/index.rst
index f80dd6a..9c1d09b 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -45,5 +45,5 @@ dependencies.
 For background and the full interface reference, see Sequince's
 `user guide <https://sequince.readthedocs.io/en/latest/user_guide.html>`_
 and `API reference <https://sequince.readthedocs.io/en/latest/api/index.html>`_.
-The examples use :external:py:class:`sequince.ParticleState` to represent the
+The examples use :external:py:class:`~sequince.state.ParticleState` to represent the
 weighted particle population.
diff --git a/pixi.lock b/pixi.lock
index 98c9df7..03f89d8 100644
--- a/pixi.lock
+++ b/pixi.lock
@@ -138,7 +138,6 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.7.22-hbd8a1cb_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/python_abi-3.13-9_cp313.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/tzdata-2026c-h151e31d_0.conda
-      - pypi: git+https://github.com/sequince-dev/sequince.git?branch=main#9968074e158e13760a9af5d5a1be0c28e554d036
       - pypi: https://files.pythonhosted.org/packages/07/ef/9b77fc80fc9bf28978d5649a3c71c0e77efe9e1966e5f608e7c3d5ba86b4/acai_control-0.1.0-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/1e/cf/83c3377e7018ee3c455153d9560c6a972b0a407075868f5e58979fc640a2/minipcn-0.3.0a1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/38/bb/d215ee7c73b61497b28a5503f9f53523f294fcc936762b7caf90e0c1c2b5/pyparsing-3.3.3-py3-none-any.whl
@@ -154,6 +153,7 @@ environments:
       - pypi: https://files.pythonhosted.org/packages/a9/df/e7c10292f348cf55178a5b3c0092a38ea68891a3945f199ae8b7b8ac9dc1/matplotlib-3.11.2-cp313-cp313-manylinux2014_x86_64.manylinux_2_17_x86_64.whl
       - pypi: https://files.pythonhosted.org/packages/ab/43/86aacc027959108b4c66eeae8b73cedb057dfa6eb3a335d05ad65197081c/kiwisolver-1.5.1-cp313-cp313-manylinux2014_x86_64.manylinux_2_17_x86_64.whl
       - pypi: https://files.pythonhosted.org/packages/b7/ce/149a00dd41f10bc29e5921b496af8b574d8413afcd5e30dfa0ed46c2cc5e/six-1.17.0-py2.py3-none-any.whl
+      - pypi: https://files.pythonhosted.org/packages/bc/bc/8d12a3ea38b7569e773efa574964110435b20ab3d9719b0185dc8d716cc5/sequince-0.1.0b1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/bd/98/ef2b6fe2903e377cbe870c3b2800d62552f1e3dbe81ce49e1923c53d1c5c/h5py-3.16.0-cp313-cp313-manylinux_2_28_x86_64.whl
       - pypi: https://files.pythonhosted.org/packages/c7/b3/fcf70b2ed935f26fc15dfd81f72f781d395b09e302af5c86ec285d63524e/array_api_extra-0.11.4-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/d6/cb/17a130e548ee1777f2a66e09240c531a9bf79454add7ef1198fe1e41c412/corner-2.3.0-py3-none-any.whl
@@ -179,7 +179,6 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/python-3.13.16-hb59dee6_101_cp313.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/readline-8.3-h8b90a29_1.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/tk-8.6.13-hbeba79b_4.conda
-      - pypi: git+https://github.com/sequince-dev/sequince.git?branch=main#9968074e158e13760a9af5d5a1be0c28e554d036
       - pypi: https://files.pythonhosted.org/packages/07/ef/9b77fc80fc9bf28978d5649a3c71c0e77efe9e1966e5f608e7c3d5ba86b4/acai_control-0.1.0-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/10/76/8803c13605b763d33d156c4678fc77f8443389c0c51c8aef707bb02015f4/pillow-12.3.0-cp313-cp313-macosx_11_0_arm64.whl
       - pypi: https://files.pythonhosted.org/packages/1e/cf/83c3377e7018ee3c455153d9560c6a972b0a407075868f5e58979fc640a2/minipcn-0.3.0a1-py3-none-any.whl
@@ -197,6 +196,7 @@ environments:
       - pypi: https://files.pythonhosted.org/packages/a9/29/2a47b700545aca050e0ed73c89ba21e08407e11f5f42a567421b220de6c1/matplotlib-3.11.2-cp313-cp313-macosx_11_0_arm64.whl
       - pypi: https://files.pythonhosted.org/packages/b0/65/5e088a45d0f43cd814bc5bec521c051d42005a472e804b1a36c48dada09b/h5py-3.16.0-cp313-cp313-macosx_11_0_arm64.whl
       - pypi: https://files.pythonhosted.org/packages/b7/ce/149a00dd41f10bc29e5921b496af8b574d8413afcd5e30dfa0ed46c2cc5e/six-1.17.0-py2.py3-none-any.whl
+      - pypi: https://files.pythonhosted.org/packages/bc/bc/8d12a3ea38b7569e773efa574964110435b20ab3d9719b0185dc8d716cc5/sequince-0.1.0b1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/c7/b3/fcf70b2ed935f26fc15dfd81f72f781d395b09e302af5c86ec285d63524e/array_api_extra-0.11.4-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/cb/f4/e410b8c913da5b3fdbb4d16db0f2d2a0952f59c4db8d52dcf2d421d82044/fonttools-4.66.1-cp313-cp313-macosx_10_13_universal2.whl
       - pypi: https://files.pythonhosted.org/packages/d6/cb/17a130e548ee1777f2a66e09240c531a9bf79454add7ef1198fe1e41c412/corner-2.3.0-py3-none-any.whl
@@ -399,8 +399,7 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/noarch/typing-extensions-4.16.0-h69aa097_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/typing_extensions-4.16.0-pyhcf101f3_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/tzdata-2026c-h151e31d_0.conda
-      - pypi: git+https://github.com/sequince-dev/sequince-flows.git?rev=cbe32939713f17be2c5deb8f813ba1ec4550ea7e#cbe32939713f17be2c5deb8f813ba1ec4550ea7e
-      - pypi: git+https://github.com/sequince-dev/sequince.git?branch=main#9968074e158e13760a9af5d5a1be0c28e554d036
+      - pypi: git+https://github.com/sequince-dev/sequince-density.git?branch=main#9c57f37db95d702eb75fc8f53d5f656db0ac7de0
       - pypi: https://files.pythonhosted.org/packages/07/ef/9b77fc80fc9bf28978d5649a3c71c0e77efe9e1966e5f608e7c3d5ba86b4/acai_control-0.1.0-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/1e/cf/83c3377e7018ee3c455153d9560c6a972b0a407075868f5e58979fc640a2/minipcn-0.3.0a1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/38/bb/d215ee7c73b61497b28a5503f9f53523f294fcc936762b7caf90e0c1c2b5/pyparsing-3.3.3-py3-none-any.whl
@@ -414,6 +413,7 @@ environments:
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       - pypi: https://files.pythonhosted.org/packages/ab/43/86aacc027959108b4c66eeae8b73cedb057dfa6eb3a335d05ad65197081c/kiwisolver-1.5.1-cp313-cp313-manylinux2014_x86_64.manylinux_2_17_x86_64.whl
       - pypi: https://files.pythonhosted.org/packages/b7/ce/149a00dd41f10bc29e5921b496af8b574d8413afcd5e30dfa0ed46c2cc5e/six-1.17.0-py2.py3-none-any.whl
+      - pypi: https://files.pythonhosted.org/packages/bc/bc/8d12a3ea38b7569e773efa574964110435b20ab3d9719b0185dc8d716cc5/sequince-0.1.0b1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/bd/98/ef2b6fe2903e377cbe870c3b2800d62552f1e3dbe81ce49e1923c53d1c5c/h5py-3.16.0-cp313-cp313-manylinux_2_28_x86_64.whl
       - pypi: https://files.pythonhosted.org/packages/c7/b3/fcf70b2ed935f26fc15dfd81f72f781d395b09e302af5c86ec285d63524e/array_api_extra-0.11.4-py3-none-any.whl
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@@ -482,8 +482,7 @@ environments:
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       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/sleef-3.9.0-hb028509_0.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/tk-8.6.13-hbeba79b_4.conda
-      - pypi: git+https://github.com/sequince-dev/sequince-flows.git?rev=cbe32939713f17be2c5deb8f813ba1ec4550ea7e#cbe32939713f17be2c5deb8f813ba1ec4550ea7e
-      - pypi: git+https://github.com/sequince-dev/sequince.git?branch=main#9968074e158e13760a9af5d5a1be0c28e554d036
+      - pypi: git+https://github.com/sequince-dev/sequince-density.git?branch=main#9c57f37db95d702eb75fc8f53d5f656db0ac7de0
       - pypi: https://files.pythonhosted.org/packages/07/ef/9b77fc80fc9bf28978d5649a3c71c0e77efe9e1966e5f608e7c3d5ba86b4/acai_control-0.1.0-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/10/76/8803c13605b763d33d156c4678fc77f8443389c0c51c8aef707bb02015f4/pillow-12.3.0-cp313-cp313-macosx_11_0_arm64.whl
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@@ -498,6 +497,7 @@ environments:
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       - pypi: https://files.pythonhosted.org/packages/b7/ce/149a00dd41f10bc29e5921b496af8b574d8413afcd5e30dfa0ed46c2cc5e/six-1.17.0-py2.py3-none-any.whl
+      - pypi: https://files.pythonhosted.org/packages/bc/bc/8d12a3ea38b7569e773efa574964110435b20ab3d9719b0185dc8d716cc5/sequince-0.1.0b1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/c7/b3/fcf70b2ed935f26fc15dfd81f72f781d395b09e302af5c86ec285d63524e/array_api_extra-0.11.4-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/cb/f4/e410b8c913da5b3fdbb4d16db0f2d2a0952f59c4db8d52dcf2d421d82044/fonttools-4.66.1-cp313-cp313-macosx_10_13_universal2.whl
       - pypi: https://files.pythonhosted.org/packages/d6/cb/17a130e548ee1777f2a66e09240c531a9bf79454add7ef1198fe1e41c412/corner-2.3.0-py3-none-any.whl
@@ -533,7 +533,6 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/noarch/ca-certificates-2026.7.22-hbd8a1cb_0.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/python_abi-3.13-9_cp313.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/tzdata-2026c-h151e31d_0.conda
-      - pypi: git+https://github.com/sequince-dev/sequince.git?branch=main#9968074e158e13760a9af5d5a1be0c28e554d036
       - pypi: https://files.pythonhosted.org/packages/07/ef/9b77fc80fc9bf28978d5649a3c71c0e77efe9e1966e5f608e7c3d5ba86b4/acai_control-0.1.0-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/1e/cf/83c3377e7018ee3c455153d9560c6a972b0a407075868f5e58979fc640a2/minipcn-0.3.0a1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/23/cd/066e86230ae37ed0be70aae89aabf03ca8d9f39c8aea0dec8029455b5540/opt_einsum-3.4.0-py3-none-any.whl
@@ -547,11 +546,15 @@ environments:
       - pypi: https://files.pythonhosted.org/packages/76/3e/0fa5690a3a8303d821a46fd35691b1b6f8a9c06b97b41847ca41aed72e90/orng-0.2.1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/86/16/1a8fd2b19544b84575cf84ef7aa3ad4c173b756d5f087c91f85d1b295777/array_api_compat-1.15.0-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/89/a5/da8ae6c6f1babe4b68e3e55d43d39b529e29774f10e0910671a6b8c86eb8/ml_dtypes-0.6.0-cp313-cp313-manylinux_2_27_x86_64.manylinux_2_28_x86_64.whl
+      - pypi: https://files.pythonhosted.org/packages/8a/69/6a93d8600c339d7687a05857c7907bd4dd8cf88691a5ea106d7a50af90a1/optax-0.2.8-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/93/b2/696029cd979f5429ec25c12767734bf0e13175d3341a2aeac59127d00ca0/optree-0.20.0-cp313-cp313-manylinux_2_27_x86_64.manylinux_2_28_x86_64.whl
+      - pypi: https://files.pythonhosted.org/packages/99/a0/24f50e0cfd432b47103677c6fc6b220acc716c4b20dc9d6021a01d7924fa/blackjax-1.7.1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/a7/03/921a3d3c75785aca9ebfbfcabfbc3a1be12e2ab5265deb026d55a5a3f83e/tqdm-4.70.1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/a9/df/e7c10292f348cf55178a5b3c0092a38ea68891a3945f199ae8b7b8ac9dc1/matplotlib-3.11.2-cp313-cp313-manylinux2014_x86_64.manylinux_2_17_x86_64.whl
       - pypi: https://files.pythonhosted.org/packages/ab/43/86aacc027959108b4c66eeae8b73cedb057dfa6eb3a335d05ad65197081c/kiwisolver-1.5.1-cp313-cp313-manylinux2014_x86_64.manylinux_2_17_x86_64.whl
+      - pypi: https://files.pythonhosted.org/packages/b3/7d/01e62f59e4166af1be6238d9f2b7f3453630c51b8044b412d05b5606532a/absl_py-2.5.1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/b7/ce/149a00dd41f10bc29e5921b496af8b574d8413afcd5e30dfa0ed46c2cc5e/six-1.17.0-py2.py3-none-any.whl
+      - pypi: https://files.pythonhosted.org/packages/bc/bc/8d12a3ea38b7569e773efa574964110435b20ab3d9719b0185dc8d716cc5/sequince-0.1.0b1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/bd/98/ef2b6fe2903e377cbe870c3b2800d62552f1e3dbe81ce49e1923c53d1c5c/h5py-3.16.0-cp313-cp313-manylinux_2_28_x86_64.whl
       - pypi: https://files.pythonhosted.org/packages/c7/b3/fcf70b2ed935f26fc15dfd81f72f781d395b09e302af5c86ec285d63524e/array_api_extra-0.11.4-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/ca/87/0c0ca8433e1135f6d1acd355cff21f31c3d433d937d6547aa545c8b060b8/jax-0.11.2-py3-none-any.whl
@@ -578,7 +581,6 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/python-3.13.16-hb59dee6_101_cp313.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/readline-8.3-h8b90a29_1.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/tk-8.6.13-hbeba79b_4.conda
-      - pypi: git+https://github.com/sequince-dev/sequince.git?branch=main#9968074e158e13760a9af5d5a1be0c28e554d036
       - pypi: https://files.pythonhosted.org/packages/07/ef/9b77fc80fc9bf28978d5649a3c71c0e77efe9e1966e5f608e7c3d5ba86b4/acai_control-0.1.0-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/10/76/8803c13605b763d33d156c4678fc77f8443389c0c51c8aef707bb02015f4/pillow-12.3.0-cp313-cp313-macosx_11_0_arm64.whl
       - pypi: https://files.pythonhosted.org/packages/1e/cf/83c3377e7018ee3c455153d9560c6a972b0a407075868f5e58979fc640a2/minipcn-0.3.0a1-py3-none-any.whl
@@ -594,11 +596,15 @@ environments:
       - pypi: https://files.pythonhosted.org/packages/76/3e/0fa5690a3a8303d821a46fd35691b1b6f8a9c06b97b41847ca41aed72e90/orng-0.2.1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/83/8c/b0ea9477fb1f0d4484bbc5cba21678cc9969704d8d7f3f158d1db35f8e14/numpy-2.5.4-cp313-cp313-macosx_11_0_arm64.whl
       - pypi: https://files.pythonhosted.org/packages/86/16/1a8fd2b19544b84575cf84ef7aa3ad4c173b756d5f087c91f85d1b295777/array_api_compat-1.15.0-py3-none-any.whl
+      - pypi: https://files.pythonhosted.org/packages/8a/69/6a93d8600c339d7687a05857c7907bd4dd8cf88691a5ea106d7a50af90a1/optax-0.2.8-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/8d/c0/85fa4951ed8fcfc54ea10367e20617b60292780999835f636a6bdbf01c34/optree-0.20.0-cp313-cp313-macosx_11_0_arm64.whl
+      - pypi: https://files.pythonhosted.org/packages/99/a0/24f50e0cfd432b47103677c6fc6b220acc716c4b20dc9d6021a01d7924fa/blackjax-1.7.1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/a7/03/921a3d3c75785aca9ebfbfcabfbc3a1be12e2ab5265deb026d55a5a3f83e/tqdm-4.70.1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/a9/29/2a47b700545aca050e0ed73c89ba21e08407e11f5f42a567421b220de6c1/matplotlib-3.11.2-cp313-cp313-macosx_11_0_arm64.whl
       - pypi: https://files.pythonhosted.org/packages/b0/65/5e088a45d0f43cd814bc5bec521c051d42005a472e804b1a36c48dada09b/h5py-3.16.0-cp313-cp313-macosx_11_0_arm64.whl
+      - pypi: https://files.pythonhosted.org/packages/b3/7d/01e62f59e4166af1be6238d9f2b7f3453630c51b8044b412d05b5606532a/absl_py-2.5.1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/b7/ce/149a00dd41f10bc29e5921b496af8b574d8413afcd5e30dfa0ed46c2cc5e/six-1.17.0-py2.py3-none-any.whl
+      - pypi: https://files.pythonhosted.org/packages/bc/bc/8d12a3ea38b7569e773efa574964110435b20ab3d9719b0185dc8d716cc5/sequince-0.1.0b1-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/c7/b3/fcf70b2ed935f26fc15dfd81f72f781d395b09e302af5c86ec285d63524e/array_api_extra-0.11.4-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/ca/87/0c0ca8433e1135f6d1acd355cff21f31c3d433d937d6547aa545c8b060b8/jax-0.11.2-py3-none-any.whl
       - pypi: https://files.pythonhosted.org/packages/cb/f4/e410b8c913da5b3fdbb4d16db0f2d2a0952f59c4db8d52dcf2d421d82044/fonttools-4.66.1-cp313-cp313-macosx_10_13_universal2.whl
@@ -3192,9 +3198,9 @@ packages:
     - zstd >=1.5.7,<1.6.0a0
   size: 433687
   timestamp: 1786599629846
-- pypi: git+https://github.com/sequince-dev/sequince-flows.git?rev=cbe32939713f17be2c5deb8f813ba1ec4550ea7e#cbe32939713f17be2c5deb8f813ba1ec4550ea7e
+- pypi: git+https://github.com/sequince-dev/sequince-density.git?branch=main#9c57f37db95d702eb75fc8f53d5f656db0ac7de0
   name: sequince-density
-  version: 0.1.dev30+gcbe329397
+  version: 0.1.dev32+g9c57f37db
   requires_dist:
   - array-api-compat>=1.5
   - numpy>=1.25.2
@@ -3208,28 +3214,6 @@ packages:
   - equinox ; extra == 'flowjax'
   - h5py>=3 ; extra == 'flowjax'
   requires_python: '>=3.11'
-- pypi: git+https://github.com/sequince-dev/sequince.git?branch=main#9968074e158e13760a9af5d5a1be0c28e554d036
-  name: sequince
-  version: 0.1.dev170+g9968074e1
-  requires_dist:
-  - acai-control>=0.1.0
-  - scipy>=1.16
-  - matplotlib>=3.5
-  - numpy>=1.25.2
-  - minipcn>=0.3.0a1
-  - array-api-compat>=1.13
-  - array-api-extra>=0.10
-  - optree>=0.19
-  - orng>=0.2.1
-  - jax>0.5.3 ; extra == 'jax'
-  - jaxlib ; extra == 'jax'
-  - blackjax>=1.2 ; extra == 'blackjax'
-  - emcee>=3.0 ; extra == 'emcee'
-  - eryn>=1.2.6 ; extra == 'eryn'
-  - numpy<2.4 ; extra == 'eryn'
-  - corner ; extra == 'corner'
-  - h5py>=3 ; extra == 'hdf5'
-  requires_python: '>=3.11'
 - pypi: https://files.pythonhosted.org/packages/07/ef/9b77fc80fc9bf28978d5649a3c71c0e77efe9e1966e5f608e7c3d5ba86b4/acai_control-0.1.0-py3-none-any.whl
   name: acai-control
   version: 0.1.0
@@ -3560,6 +3544,31 @@ packages:
   - pylint>=2.6.0 ; extra == 'dev'
   - pyink ; extra == 'dev'
   requires_python: '>=3.10'
+- pypi: https://files.pythonhosted.org/packages/8a/69/6a93d8600c339d7687a05857c7907bd4dd8cf88691a5ea106d7a50af90a1/optax-0.2.8-py3-none-any.whl
+  name: optax
+  version: 0.2.8
+  sha256: e3ca2d36c99daab1800ae9dbc0545034382d6bc780b24d969e1b0df65fa31cb4
+  requires_dist:
+  - absl-py>=0.7.1
+  - jax>=0.5.3
+  - jaxlib>=0.5.3
+  - numpy>=1.18.0
+  - sphinx>=6.0.0 ; extra == 'docs'
+  - sphinx-book-theme>=1.0.1 ; extra == 'docs'
+  - sphinxcontrib-katex ; extra == 'docs'
+  - sphinx-autodoc-typehints ; extra == 'docs'
+  - ipython>=8.8.0 ; extra == 'docs'
+  - myst-nb>=1.0.0 ; extra == 'docs'
+  - matplotlib>=3.5.0 ; extra == 'docs'
+  - sphinx-gallery>=0.14.0 ; extra == 'docs'
+  - sphinx-collections>=0.0.1 ; extra == 'docs'
+  - flax ; extra == 'docs'
+  - sphinx-contributors ; extra == 'docs'
+  - setuptools ; extra == 'docs'
+  - flax>=0.5.3 ; extra == 'test'
+  - scipy>=1.7.1 ; extra == 'test'
+  - scikit-learn ; extra == 'test'
+  requires_python: '>=3.10'
 - pypi: https://files.pythonhosted.org/packages/8d/c0/85fa4951ed8fcfc54ea10367e20617b60292780999835f636a6bdbf01c34/optree-0.20.0-cp313-cp313-macosx_11_0_arm64.whl
   name: optree
   version: 0.20.0
@@ -3669,6 +3678,20 @@ packages:
   - sphinx==7.3.7 ; extra == 'docs'
   - pytest>=8.0.0 ; extra == 'test'
   requires_python: '>=3.10'
+- pypi: https://files.pythonhosted.org/packages/99/a0/24f50e0cfd432b47103677c6fc6b220acc716c4b20dc9d6021a01d7924fa/blackjax-1.7.1-py3-none-any.whl
+  name: blackjax
+  version: 1.7.1
+  sha256: be2c7f982f4ab3afef2dd5f075dae271023fdec3d9c5d8b599ba7f2f281524fa
+  requires_dist:
+  - jax>=0.9.0
+  - jaxlib>=0.9.0
+  - numpy>=1.25
+  - optax>=0.2.3
+  - scipy>=1.13
+  - typing-extensions>=4.4.0
+  - tqdm>=4.66 ; extra == 'progress'
+  - jax-tap>=0.3.1 ; extra == 'progress'
+  requires_python: '>=3.11'
 - pypi: https://files.pythonhosted.org/packages/a7/03/921a3d3c75785aca9ebfbfcabfbc3a1be12e2ab5265deb026d55a5a3f83e/tqdm-4.70.1-py3-none-any.whl
   name: tqdm
   version: 4.70.1
@@ -3725,11 +3748,39 @@ packages:
   requires_dist:
   - numpy>=1.21.2
   requires_python: '>=3.10'
+- pypi: https://files.pythonhosted.org/packages/b3/7d/01e62f59e4166af1be6238d9f2b7f3453630c51b8044b412d05b5606532a/absl_py-2.5.1-py3-none-any.whl
+  name: absl-py
+  version: 2.5.1
+  sha256: 721200f2f0e9960f2ca9dc3a2a706b201f5f75d812c158f059cbbe29eeafbdb8
+  requires_python: '>=3.10'
 - pypi: https://files.pythonhosted.org/packages/b7/ce/149a00dd41f10bc29e5921b496af8b574d8413afcd5e30dfa0ed46c2cc5e/six-1.17.0-py2.py3-none-any.whl
   name: six
   version: 1.17.0
   sha256: 4721f391ed90541fddacab5acf947aa0d3dc7d27b2e1e8eda2be8970586c3274
   requires_python: '>=2.7,!=3.0.*,!=3.1.*,!=3.2.*'
+- pypi: https://files.pythonhosted.org/packages/bc/bc/8d12a3ea38b7569e773efa574964110435b20ab3d9719b0185dc8d716cc5/sequince-0.1.0b1-py3-none-any.whl
+  name: sequince
+  version: 0.1.0b1
+  sha256: a4c85cfe9c6c0ebd3ebeed5953fec79ef58d6b365df3232d8fff57e8d4954b40
+  requires_dist:
+  - acai-control>=0.1.0
+  - scipy>=1.16
+  - matplotlib>=3.5
+  - numpy>=1.25.2
+  - minipcn>=0.3.0a1
+  - array-api-compat>=1.13
+  - array-api-extra>=0.10
+  - optree>=0.19
+  - orng>=0.2.1
+  - jax>0.5.3 ; extra == 'jax'
+  - jaxlib ; extra == 'jax'
+  - blackjax>=1.2 ; extra == 'blackjax'
+  - emcee>=3.0 ; extra == 'emcee'
+  - eryn>=1.2.6 ; extra == 'eryn'
+  - numpy<2.4 ; extra == 'eryn'
+  - corner ; extra == 'corner'
+  - h5py>=3 ; extra == 'hdf5'
+  requires_python: '>=3.11'
 - pypi: https://files.pythonhosted.org/packages/bd/98/ef2b6fe2903e377cbe870c3b2800d62552f1e3dbe81ce49e1923c53d1c5c/h5py-3.16.0-cp313-cp313-manylinux_2_28_x86_64.whl
   name: h5py
   version: 3.16.0
diff --git a/pyproject.toml b/pyproject.toml
index 17729a7..4d33e4d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -22,6 +22,7 @@ sequince = { version = "*", extras = ["corner", "hdf5"] }
 
 [tool.pixi.feature.jax.pypi-dependencies]
 jax = ">0.5.3"
+blackjax = ">=1.2"
 
 [tool.pixi.feature.jax.activation.env]
 JAX_PLATFORMS = "cpu"
@@ -30,7 +31,8 @@ JAX_PLATFORMS = "cpu"
 pytorch-cpu = "*"
 
 [tool.pixi.feature.flow.pypi-dependencies]
-sequince-density = { version = "*", extras = ["zuko"] }
+# Use the public repository until sequince-density is released on PyPI.
+sequince-density = { git = "https://github.com/sequince-dev/sequince-density.git", branch = "main", extras = ["zuko"] }
 
 [tool.pixi.feature.docs.dependencies]
 sphinx = "8.2.*"
diff --git a/scripts/docs_pipeline.py b/scripts/docs_pipeline.py
index 18ad5bf..4a11275 100644
--- a/scripts/docs_pipeline.py
+++ b/scripts/docs_pipeline.py
@@ -16,6 +16,7 @@
 import sys
 import tarfile
 import tempfile
+import urllib.error
 import urllib.request
 from pathlib import Path
 
@@ -128,14 +129,14 @@ def resolved_versions(example: dict) -> dict[str, str]:
             ):
                 if any("git+" in source for source, _ in matches):
                     raise ValueError(
-                        f"Stale Git lock for {package}; run pixi update sequince sequince-density after the releases are available"
+                        f"Stale Git lock for {package}; run pixi update sequince sequince-density"
                     )
             versions[package] = found.pop()
     return versions
 
 
 def refresh() -> None:
-    """Resolve the latest released dependencies once per execution batch."""
+    """Resolve example dependencies once per execution batch."""
     subprocess.run(
         ["pixi", "update", "sequince", "sequince-density"],
         cwd=ROOT,
@@ -486,13 +487,22 @@ def unpack(
 
 
 def check_latest() -> None:
-    """Stop stale latest builds both before Sphinx and before RTD upload."""
+    """Stop stale latest and PR builds before Sphinx and before RTD upload."""
     if os.environ.get("READTHEDOCS_VERSION") == "latest":
         remote = git("ls-remote", "origin", "refs/heads/main").split()[0]
         if git("rev-parse", "HEAD") != remote:
             raise ValueError(
                 "Stale latest checkout: main advanced; rebuild latest"
             )
+    elif os.environ.get("READTHEDOCS_VERSION_TYPE") == "external":
+        number = os.environ["READTHEDOCS_VERSION"]
+        if not number.isascii() or not number.isdigit():
+            raise ValueError("Invalid Read the Docs PR number")
+        remote = git("ls-remote", "origin", f"refs/pull/{number}/head")
+        if not remote or git("rev-parse", "HEAD") != remote.split()[0]:
+            raise ValueError(
+                "Stale PR checkout: head advanced; rebuild preview"
+            )
 
 
 def fetch() -> None:
@@ -501,16 +511,30 @@ def fetch() -> None:
     sha = git("rev-parse", "HEAD")
     # No credentials: RTD Community and these assets must be publicly readable.
     name = f"docs-outputs-{sha}.tar.gz"
-    base = (
-        f"https://github.com/{REPOSITORY}/releases/download/docs-output-{sha}"
-    )
+    tag = f"docs-output-{sha}"
+    external = os.environ.get("READTHEDOCS_VERSION_TYPE") == "external"
+    if external:
+        number = os.environ["READTHEDOCS_VERSION"]
+        if not number.isascii() or not number.isdigit():
+            raise ValueError("Invalid Read the Docs PR number")
+        tag = f"docs-pr-{number}-{sha}"
+    base = f"https://github.com/{REPOSITORY}/releases/download/{tag}"
     with tempfile.TemporaryDirectory() as tmp:
         path = Path(tmp) / name
         for suffix in ("", ".sha256"):
-            with urllib.request.urlopen(
-                base + "/" + name + suffix, timeout=60
-            ) as response:
-                Path(str(path) + suffix).write_bytes(response.read())
+            try:
+                with urllib.request.urlopen(
+                    base + "/" + name + suffix, timeout=60
+                ) as response:
+                    Path(str(path) + suffix).write_bytes(response.read())
+            except urllib.error.HTTPError as error:
+                if external and not suffix and error.code == 404:
+                    print(
+                        "PR outputs are not published yet; GitHub Actions "
+                        "will request a preview after publication."
+                    )
+                    raise SystemExit(183) from error
+                raise
         expected = Path(str(path) + ".sha256").read_text().split()
         if expected != [digest(path), name]:
             raise ValueError("Downloaded bundle checksum mismatch")
diff --git a/scripts/publish_docs.py b/scripts/publish_docs.py
index 17bdf21..ce32516 100644
--- a/scripts/publish_docs.py
+++ b/scripts/publish_docs.py
@@ -39,16 +39,8 @@ def wait_idle(project: str, deadline: float) -> None:
         time.sleep(20)
 
 
-def main() -> None:
-    """Publish only main, verify assets, and monitor the triggered build."""
-    sha = git("rev-parse", "HEAD")
-    if git("ls-remote", "origin", "refs/heads/main").split()[0] != sha:
-        print("Main has advanced; skipping stale publication")
-        return
-    if set(git("diff", "--name-only", "HEAD").splitlines()) - {"pixi.lock"}:
-        raise ValueError("Refusing publication from a modified checkout")
-    path = bundle()
-    tag = f"docs-output-{sha}"
+def publish_assets(path: Path, tag: str, target: str) -> None:
+    """Publish a bundle and checksum without replacing existing assets."""
     # Dedicated prereleases in the examples repository cannot become a library
     # release or GitHub's latest software release.
     view = subprocess.run(
@@ -63,11 +55,11 @@ def main() -> None:
             "create",
             tag,
             "--target",
-            sha,
+            target,
             "--title",
             tag,
             "--notes",
-            f"Validated example documentation outputs for {sha}.",
+            f"Example documentation outputs: {tag}.",
             "--prerelease",
             "--latest=false",
             "--draft",
@@ -98,14 +90,13 @@ def main() -> None:
             gh("release", "upload", tag, str(asset))
     if release["isDraft"]:
         gh("release", "edit", tag, "--draft=false", "--latest=false")
-    # The workflow's non-cancelling concurrency lock covers this whole wait.
-    project = urllib.parse.quote(os.environ["RTD_PROJECT"], safe="")
-    deadline = time.monotonic() + 2400
-    wait_idle(project, deadline)
-    if git("ls-remote", "origin", "refs/heads/main").split()[0] != sha:
-        print("Bundle uploaded; main advanced, skipping latest trigger")
-        return
-    result = rtd(f"projects/{project}/versions/latest/builds/", "POST")
+
+
+def build_version(
+    project: str, version: str, sha: str, deadline: float
+) -> None:
+    """Trigger and monitor an RTD version, requiring the expected commit."""
+    result = rtd(f"projects/{project}/versions/{version}/builds/", "POST")
     build_id = result["build"]["id"]
     while True:
         build = rtd(f"projects/{project}/builds/{build_id}/")
@@ -119,10 +110,29 @@ def main() -> None:
     if not build["success"] or build["commit"] != sha:
         raise ValueError(
             f"RTD build {build_id} failed or checked out another commit; "
-            "inspect RTD and rerun the workflow for current main"
+            "inspect RTD and rerun the workflow for the current commit"
         )
     print(f"RTD build {build_id} succeeded for {sha}")
 
 
+def main() -> None:
+    """Publish only main, verify assets, and monitor the triggered build."""
+    sha = git("rev-parse", "HEAD")
+    if git("ls-remote", "origin", "refs/heads/main").split()[0] != sha:
+        print("Main has advanced; skipping stale publication")
+        return
+    if set(git("diff", "--name-only", "HEAD").splitlines()) - {"pixi.lock"}:
+        raise ValueError("Refusing publication from a modified checkout")
+    publish_assets(bundle(), f"docs-output-{sha}", sha)
+    # The workflow's non-cancelling concurrency lock covers this whole wait.
+    project = urllib.parse.quote(os.environ["RTD_PROJECT"], safe="")
+    deadline = time.monotonic() + 2400
+    wait_idle(project, deadline)
+    if git("ls-remote", "origin", "refs/heads/main").split()[0] != sha:
+        print("Bundle uploaded; main advanced, skipping latest trigger")
+        return
+    build_version(project, "latest", sha, deadline)
+
+
 if __name__ == "__main__":
     main()
diff --git a/scripts/publish_pr_docs.py b/scripts/publish_pr_docs.py
new file mode 100644
index 0000000..5f57edb
--- /dev/null
+++ b/scripts/publish_pr_docs.py
@@ -0,0 +1,175 @@
+"""Publish PR bundles as data using only trusted default-branch code."""
+
+from __future__ import annotations
+
+import gzip
+import hashlib
+import io
+import json
+import os
+import re
+import subprocess
+import tarfile
+import tempfile
+import time
+import urllib.parse
+import zipfile
+from pathlib import Path
+
+from docs_pipeline import REPOSITORY, ROOT, digest, git
+from publish_docs import build_version, gh, publish_assets, wait_idle
+
+MAX_BYTES = 128 * 1024 * 1024
+
+
+def api(path: str) -> dict | list:
+    """Read GitHub metadata from the fixed examples repository."""
+    return json.loads(gh("api", f"repos/{REPOSITORY}/{path}"))
+
+
+def current_pr(sha: str) -> dict | None:
+    """Find the open PR whose current head is the completed run's commit."""
+    matches = [
+        pr
+        for pr in api(f"commits/{sha}/pulls?per_page=100")
+        if pr["state"] == "open"
+        and pr["head"]["sha"] == sha
+        and pr["base"]["repo"]["full_name"] == REPOSITORY
+    ]
+    if len(matches) > 1:
+        raise ValueError("Multiple open PRs for the same head commit")
+    return matches[0] if matches else None
+
+
+def verify_bundle(path: Path, sha: str) -> None:
+    """Check untrusted archive data without extracting or executing files."""
+    hashes = {}
+    manifest = None
+    size = 0
+    # Bound decompression before parsing tar/PAX headers as well as file data.
+    with gzip.open(path, "rb") as compressed:
+        contents = compressed.read(MAX_BYTES + 1)
+    if len(contents) > MAX_BYTES:
+        raise ValueError("Oversized decompressed PR bundle")
+    with tarfile.open(fileobj=io.BytesIO(contents), mode="r:") as archive:
+        for member in archive:
+            name = Path(member.name)
+            size += member.size
+            if (
+                not member.isfile()
+                or name.is_absolute()
+                or ".." in name.parts
+                or str(name) != member.name
+                or member.name in hashes
+                or member.size < 0
+                or size > MAX_BYTES
+                or len(hashes) >= 2000
+            ):
+                raise ValueError("Unsafe or oversized PR bundle")
+            stream = archive.extractfile(member)
+            if stream is None:
+                raise ValueError("Unreadable PR bundle member")
+            data = stream.read()
+            hashes[member.name] = hashlib.sha256(data).hexdigest()
+            if member.name == "bundle-manifest.json":
+                manifest = json.loads(data)
+            elif member.name.endswith("/metadata.json"):
+                if json.loads(data)["source_commit"] != sha:
+                    raise ValueError("PR metadata commit mismatch")
+    hashes.pop("bundle-manifest.json", None)
+    if (
+        not manifest
+        or manifest["schema"] != 1
+        or manifest["source_commit"] != sha
+        or manifest["files"] != hashes
+        or "execution-pixi.lock" not in hashes
+        or not any(name.endswith("/metadata.json") for name in hashes)
+    ):
+        raise ValueError("PR bundle manifest/commit/checksum mismatch")
+
+
+def download_bundle(run_id: int, sha: str, destination: Path) -> Path:
+    """Read only the named artifact from this run into an isolated directory."""
+    artifacts = api(f"actions/runs/{run_id}/artifacts?per_page=100")
+    matches = [
+        item
+        for item in artifacts["artifacts"]
+        if item["name"] == "validated-bundle" and not item["expired"]
+    ]
+    if len(matches) != 1 or matches[0]["size_in_bytes"] > MAX_BYTES:
+        raise ValueError("Missing, ambiguous or oversized PR artifact")
+    artifact_id = int(matches[0]["id"])
+    zipped = destination / "artifact.zip"
+    with zipped.open("wb") as stream:
+        subprocess.run(
+            [
+                "gh",
+                "api",
+                f"repos/{REPOSITORY}/actions/artifacts/{artifact_id}/zip",
+            ],
+            cwd=ROOT,
+            stdout=stream,
+            check=True,
+        )
+    if zipped.stat().st_size > MAX_BYTES:
+        raise ValueError("Oversized PR artifact download")
+    path = destination / f"docs-outputs-{sha}.tar.gz"
+    expected = {path.name, path.name + ".sha256"}
+    with zipfile.ZipFile(zipped) as archive:
+        members = archive.infolist()
+        if (
+            len(members) != 2
+            or {member.filename for member in members} != expected
+            or sum(member.file_size for member in members) > MAX_BYTES
+        ):
+            raise ValueError("Unexpected files in PR artifact")
+        for name in expected:
+            (destination / name).write_bytes(archive.read(name))
+    checksum = Path(str(path) + ".sha256").read_text().split()
+    if checksum != [digest(path), path.name]:
+        raise ValueError("PR artifact checksum mismatch")
+    verify_bundle(path, sha)
+    return path
+
+
+def main() -> None:
+    """Publish successful current PR runs, then request their RTD preview."""
+    event = json.loads(Path(os.environ["GITHUB_EVENT_PATH"]).read_text())
+    run_id = int(event["workflow_run"]["id"])
+    run = api(f"actions/runs/{run_id}")
+    if (
+        run["event"] != "pull_request"
+        or run["conclusion"] != "success"
+        or run["path"] != ".github/workflows/documentation.yml"
+        or run["repository"]["full_name"] != REPOSITORY
+    ):
+        raise ValueError("Unexpected workflow run for PR publication")
+    sha = run["head_sha"]
+    if not re.fullmatch(r"[0-9a-f]{40}", sha):
+        raise ValueError("Invalid workflow head commit")
+    pr = current_pr(sha)
+    if pr is None:
+        print("PR closed or advanced; skipping stale publication")
+        return
+    number = int(pr["number"])
+    with tempfile.TemporaryDirectory(prefix="pr-docs-") as tmp:
+        path = download_bundle(run_id, sha, Path(tmp))
+        current = current_pr(sha)
+        if current is None or current["number"] != number:
+            print("PR changed; skipping stale publication")
+            return
+        # Tag only the trusted checkout; PR data has a separate release namespace.
+        publish_assets(
+            path, f"docs-pr-{number}-{sha}", git("rev-parse", "HEAD")
+        )
+    project = urllib.parse.quote(os.environ["RTD_PROJECT"], safe="")
+    deadline = time.monotonic() + 2400
+    wait_idle(project, deadline)
+    if current_pr(sha) is None:
+        print("Bundle uploaded; PR closed or advanced, skipping preview")
+        return
+    build_version(project, str(number), sha, deadline)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tests/test_docs_pipeline.py b/tests/test_docs_pipeline.py
index 4c71d44..5548f56 100644
--- a/tests/test_docs_pipeline.py
+++ b/tests/test_docs_pipeline.py
@@ -16,6 +16,70 @@
 read_resolved_versions = pipeline.resolved_versions
 
 
+@pytest.mark.parametrize(
+    ("external", "status", "suffix", "cancel"),
+    [
+        (True, 404, "", True),
+        (False, 404, "", False),
+        (True, 403, "", False),
+        (True, 404, ".sha256", False),
+    ],
+)
+def test_pending_pr_bundle(
+    monkeypatch: pytest.MonkeyPatch,
+    external: bool,
+    status: int,
+    suffix: str,
+    cancel: bool,
+) -> None:
+    """Only a missing PR bundle cancels; broken published assets still fail."""
+    from urllib.error import HTTPError
+
+    monkeypatch.setenv(
+        "READTHEDOCS_VERSION_TYPE", "external" if external else "branch"
+    )
+    monkeypatch.setenv("READTHEDOCS_VERSION", "17" if external else "latest")
+    monkeypatch.setattr(pipeline, "git", lambda *args: "a" * 40)
+    monkeypatch.setattr(pipeline, "check_latest", lambda: None)
+
+    def download(url: str, **kwargs: object) -> io.BytesIO:
+        tag = "docs-pr-17-" if external else "docs-output-"
+        assert f"/releases/download/{tag}{'a' * 40}/" in url
+        if not suffix or url.endswith(suffix):
+            raise HTTPError(url, status, "unavailable", {}, None)
+        return io.BytesIO(b"bundle")
+
+    monkeypatch.setattr(pipeline.urllib.request, "urlopen", download)
+    if cancel:
+        with pytest.raises(SystemExit) as error:
+            pipeline.fetch()
+        assert error.value.code == 183
+    else:
+        with pytest.raises(HTTPError):
+            pipeline.fetch()
+
+
+def test_fetch_pr_restores_exact_bundle(
+    outputs: Path, tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Fetch a PR's actual archive through the full provenance checks."""
+    monkeypatch.setattr(pipeline, "BUNDLES", tmp_path)
+    monkeypatch.setattr(pipeline, "GENERATED", tmp_path / "generated")
+    path = pipeline.bundle()
+    data = path.read_bytes()
+    checksum = Path(str(path) + ".sha256").read_bytes()
+    monkeypatch.setenv("READTHEDOCS_VERSION_TYPE", "external")
+    monkeypatch.setenv("READTHEDOCS_VERSION", "17")
+
+    def download(url: str, **kwargs: object) -> io.BytesIO:
+        assert f"/docs-pr-17-{'a' * 40}/" in url
+        return io.BytesIO(checksum if url.endswith(".sha256") else data)
+
+    monkeypatch.setattr(pipeline.urllib.request, "urlopen", download)
+    pipeline.fetch()
+    assert (pipeline.GENERATED / "results/gaussian/metadata.json").is_file()
+
+
 @pytest.fixture(autouse=True)
 def release_versions(monkeypatch: pytest.MonkeyPatch) -> None:
     """Use synthetic release versions; no unavailable packages are resolved."""
@@ -141,6 +205,21 @@ def test_latest_checkout_guard(monkeypatch: pytest.MonkeyPatch) -> None:
         pipeline.check_latest()
 
 
+def test_pr_checkout_guard(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("READTHEDOCS_VERSION", "17")
+    monkeypatch.setenv("READTHEDOCS_VERSION_TYPE", "external")
+
+    def git(*args: str) -> str:
+        if args[0] == "ls-remote":
+            assert args[-1] == "refs/pull/17/head"
+            return "b" * 40
+        return "a" * 40
+
+    monkeypatch.setattr(pipeline, "git", git)
+    with pytest.raises(ValueError, match="Stale PR checkout"):
+        pipeline.check_latest()
+
+
 def test_missing_output_root_is_actionable(tmp_path: Path) -> None:
     with pytest.raises(ValueError, match="missing example outputs:.*gaussian"):
         pipeline.validate(tmp_path / "absent")
diff --git a/tests/test_publish_pr_docs.py b/tests/test_publish_pr_docs.py
new file mode 100644
index 0000000..3db4ff8
--- /dev/null
+++ b/tests/test_publish_pr_docs.py
@@ -0,0 +1,213 @@
+"""Exercise PR publication without credentials, sampling or external writes."""
+
+from __future__ import annotations
+
+import hashlib
+import io
+import json
+import sys
+import tarfile
+import zipfile
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "scripts"))
+import publish_pr_docs as publisher  # noqa: E402
+
+SHA = "a" * 40
+
+
+def make_bundle(path: Path, sha: str = SHA, unsafe: bool = False) -> None:
+    """Write a small archive with the real transport manifest format."""
+    files = {
+        "execution-pixi.lock": b"lock",
+        "gaussian/metadata.json": json.dumps({"source_commit": sha}).encode(),
+    }
+    if unsafe:
+        files["../escape"] = b"bad"
+    files["bundle-manifest.json"] = json.dumps(
+        {
+            "schema": 1,
+            "source_commit": sha,
+            "files": {
+                name: hashlib.sha256(data).hexdigest()
+                for name, data in files.items()
+            },
+        }
+    ).encode()
+    with tarfile.open(path, "w:gz") as archive:
+        for name, data in files.items():
+            member = tarfile.TarInfo(name)
+            member.size = len(data)
+            archive.addfile(member, io.BytesIO(data))
+
+
+@pytest.mark.parametrize("failure", [None, "commit", "path", "size"])
+def test_archive_validation(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch, failure: str | None
+) -> None:
+    path = tmp_path / "outputs.tar.gz"
+    make_bundle(
+        path, "b" * 40 if failure == "commit" else SHA, failure == "path"
+    )
+    if failure == "size":
+        monkeypatch.setattr(publisher, "MAX_BYTES", 1)
+    if failure:
+        with pytest.raises(ValueError):
+            publisher.verify_bundle(path, SHA)
+    else:
+        publisher.verify_bundle(path, SHA)
+    assert not (tmp_path.parent / "escape").exists()
+
+
+@pytest.mark.parametrize("failure", [None, "zip-path", "checksum"])
+def test_download_from_exact_run(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch, failure: str | None
+) -> None:
+    source = tmp_path / f"docs-outputs-{SHA}.tar.gz"
+    make_bundle(source)
+    zipped = io.BytesIO()
+    with zipfile.ZipFile(zipped, "w") as archive:
+        name = "../escape" if failure == "zip-path" else source.name
+        archive.writestr(name, source.read_bytes())
+        archive.writestr(
+            source.name + ".sha256",
+            f"{'wrong' if failure == 'checksum' else publisher.digest(source)}"
+            f"  {source.name}\n",
+        )
+
+    def api(path: str) -> dict:
+        assert path == "actions/runs/123/artifacts?per_page=100"
+        return {
+            "artifacts": [
+                {
+                    "id": 456,
+                    "name": "validated-bundle",
+                    "expired": False,
+                    "size_in_bytes": len(zipped.getvalue()),
+                }
+            ]
+        }
+
+    def download(args: list, **kwargs: object) -> None:
+        assert args[-1].endswith("actions/artifacts/456/zip")
+        kwargs["stdout"].write(zipped.getvalue())
+
+    monkeypatch.setattr(publisher, "api", api)
+    monkeypatch.setattr(publisher.subprocess, "run", download)
+    destination = tmp_path / "download"
+    destination.mkdir()
+    if failure:
+        with pytest.raises(ValueError):
+            publisher.download_bundle(123, SHA, destination)
+    else:
+        result = publisher.download_bundle(123, SHA, destination)
+        assert result.read_bytes() == source.read_bytes()
+    assert not (tmp_path / "escape").exists()
+
+
+@pytest.fixture
+def publication(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> list:
+    """Record the separate trusted publication path for a successful PR run."""
+    calls = []
+    event = tmp_path / "event.json"
+    event.write_text(json.dumps({"workflow_run": {"id": 123}}))
+    monkeypatch.setenv("GITHUB_EVENT_PATH", str(event))
+    monkeypatch.setenv("RTD_PROJECT", "examples")
+    monkeypatch.setattr(
+        publisher,
+        "api",
+        lambda path: {
+            "event": "pull_request",
+            "conclusion": "success",
+            "path": ".github/workflows/documentation.yml",
+            "repository": {"full_name": publisher.REPOSITORY},
+            "head_sha": SHA,
+        },
+    )
+    monkeypatch.setattr(publisher, "current_pr", lambda sha: {"number": 17})
+    monkeypatch.setattr(publisher, "git", lambda *args: "b" * 40)
+    monkeypatch.setattr(
+        publisher,
+        "download_bundle",
+        lambda run_id, sha, directory: calls.append(("download", run_id, sha))
+        or directory / "bundle.tar.gz",
+    )
+    monkeypatch.setattr(
+        publisher,
+        "publish_assets",
+        lambda path, tag, target: calls.append(("publish", tag, target)),
+    )
+    monkeypatch.setattr(
+        publisher,
+        "wait_idle",
+        lambda *args: calls.append(("wait",)),
+    )
+    monkeypatch.setattr(
+        publisher,
+        "build_version",
+        lambda project, version, sha, deadline: calls.append(
+            ("build", project, version, sha)
+        ),
+    )
+    return calls
+
+
+def test_publish_pr_before_preview(publication: list) -> None:
+    publisher.main()
+    assert publication == [
+        ("download", 123, SHA),
+        ("publish", f"docs-pr-17-{SHA}", "b" * 40),
+        ("wait",),
+        ("build", "examples", "17", SHA),
+    ]
+
+
+@pytest.mark.parametrize("advance_at", [0, 1, 2])
+def test_stale_or_closed_pr(
+    publication: list, monkeypatch: pytest.MonkeyPatch, advance_at: int
+) -> None:
+    responses = iter([{"number": 17}] * advance_at + [None])
+    monkeypatch.setattr(publisher, "current_pr", lambda sha: next(responses))
+    publisher.main()
+    assert not any(call[0] == "build" for call in publication)
+    if advance_at < 2:
+        assert not any(call[0] == "publish" for call in publication)
+
+
+@pytest.mark.parametrize(
+    ("field", "value"),
+    [("event", "push"), ("conclusion", "failure"), ("path", "other.yml")],
+)
+def test_unexpected_run_rejected(
+    publication: list,
+    monkeypatch: pytest.MonkeyPatch,
+    field: str,
+    value: str,
+) -> None:
+    original = publisher.api
+    monkeypatch.setattr(
+        publisher, "api", lambda path: original(path) | {field: value}
+    )
+    with pytest.raises(ValueError, match="Unexpected workflow"):
+        publisher.main()
+    assert not publication
+
+
+def test_current_pr_uses_github_metadata(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    records = [
+        {
+            "number": 17,
+            "state": "open",
+            "head": {"sha": SHA},
+            "base": {"repo": {"full_name": publisher.REPOSITORY}},
+        }
+    ]
+    monkeypatch.setattr(publisher, "api", lambda path: records)
+    assert publisher.current_pr(SHA)["number"] == 17
+    assert publisher.current_pr("b" * 40) is None
+    records[0]["state"] = "closed"
+    assert publisher.current_pr(SHA) is None