diff --git a/.github/actions/sync-version-from-dispatch/action.yml b/.github/actions/sync-version-from-dispatch/action.yml
new file mode 100644
index 0000000..4f09014
--- /dev/null
+++ b/.github/actions/sync-version-from-dispatch/action.yml
@@ -0,0 +1,60 @@
+name: Sync version from dispatch payload
+description: >-
+  Rewrite the package version in pyproject.toml and agent_assembly/__init__.py
+  to match the upstream agent-assembly release tag carried in the
+  repository_dispatch client_payload, BEFORE maturin reads pyproject.toml.
+
+  Without this, maturin would build whatever version is currently checked in
+  on master (which lags the upstream bumper), so the wheel filename would
+  collide with an already-published PyPI version. See AAASM-2459 for the
+  alpha-4 incident that motivated this action.
+
+  When `release_tag` is empty (workflow_dispatch dry-run mode), the step is a
+  no-op and the files keep whatever version is on master — useful for local
+  CI smoke tests.
+
+inputs:
+  release_tag:
+    description: >-
+      Upstream agent-assembly release tag from
+      `github.event.client_payload.release_tag` (e.g. `v0.0.1-alpha.4`).
+      Empty string is allowed and treated as a no-op (dry-run).
+    required: true
+
+runs:
+  using: composite
+  steps:
+    - name: Sync pyproject.toml + __init__.py version
+      shell: bash
+      env:
+        AASM_TAG: ${{ inputs.release_tag }}
+      run: |
+        set -euo pipefail
+        if [ -z "${AASM_TAG}" ]; then
+          echo "AASM_TAG is empty (workflow_dispatch dry-run) — leaving version files untouched."
+          exit 0
+        fi
+        # PEP-440 conversion from git tag form:
+        #   v0.0.1-alpha.4 -> 0.0.1a4
+        #   v0.0.1-beta.2  -> 0.0.1b2   (not used today; future-proofing)
+        #   v0.0.1-rc.1    -> 0.0.1rc1  (not used today; future-proofing)
+        #   v1.2.3         -> 1.2.3
+        pep440="${AASM_TAG#v}"
+        pep440="${pep440//-alpha./a}"
+        pep440="${pep440//-beta./b}"
+        pep440="${pep440//-rc./rc}"
+        echo "Mapped upstream tag '${AASM_TAG}' to PEP-440 version '${pep440}'"
+
+        # pyproject.toml: line 7 currently `version = "0.0.2"`. sed in place.
+        sed -i.bak "s|^version = \"[^\"]*\"|version = \"${pep440}\"|" pyproject.toml
+        rm -f pyproject.toml.bak
+
+        # __version__ lives in agent_assembly/__init__.py (verified for AAASM-2459).
+        sed -i.bak "s|^__version__ = \"[^\"]*\"|__version__ = \"${pep440}\"|" agent_assembly/__init__.py
+        rm -f agent_assembly/__init__.py.bak
+
+        echo "--- pyproject.toml version line ---"
+        grep -n '^version = ' pyproject.toml
+        echo "--- agent_assembly/__init__.py __version__ line ---"
+        grep -n '^__version__ = ' agent_assembly/__init__.py
+        echo "Version sync complete: building wheel as agent-assembly==${pep440}"
diff --git a/.github/workflows/release-python.yml b/.github/workflows/release-python.yml
index d0765e7..ae6c284 100644
--- a/.github/workflows/release-python.yml
+++ b/.github/workflows/release-python.yml
@@ -44,6 +44,10 @@ jobs:
       - uses: actions/setup-python@v6
         with:
           python-version: ${{ env.PYTHON_VERSION }}
+      - name: Sync version from dispatch payload
+        uses: ./.github/actions/sync-version-from-dispatch
+        with:
+          release_tag: ${{ github.event.client_payload.release_tag }}
       - name: Build source distribution
         uses: PyO3/maturin-action@v1
         with:
@@ -86,6 +90,10 @@ jobs:
           rm -f agent_assembly/bin/aasm-x86_64-unknown-linux-gnu.tar.gz
           chmod +x agent_assembly/bin/aasm
           echo "Bundled aasm binary into wheel"
+      - name: Sync version from dispatch payload
+        uses: ./.github/actions/sync-version-from-dispatch
+        with:
+          release_tag: ${{ github.event.client_payload.release_tag }}
       - name: Build wheel
         uses: PyO3/maturin-action@v1
         with:
@@ -154,6 +162,10 @@ jobs:
           rm -f agent_assembly/bin/aasm-aarch64-unknown-linux-gnu.tar.gz
           chmod +x agent_assembly/bin/aasm
           echo "Bundled aasm binary into wheel"
+      - name: Sync version from dispatch payload
+        uses: ./.github/actions/sync-version-from-dispatch
+        with:
+          release_tag: ${{ github.event.client_payload.release_tag }}
       - name: Build wheel
         uses: PyO3/maturin-action@v1
         with:
@@ -216,6 +228,10 @@ jobs:
           echo "Bundled aasm binary into wheel"
       - name: Install protoc (macOS)
         run: brew install protobuf
+      - name: Sync version from dispatch payload
+        uses: ./.github/actions/sync-version-from-dispatch
+        with:
+          release_tag: ${{ github.event.client_payload.release_tag }}
       - name: Build wheel
         uses: PyO3/maturin-action@v1
         with:
@@ -259,6 +275,10 @@ jobs:
           echo "Bundled aasm binary into wheel"
       - name: Install protoc (macOS)
         run: brew install protobuf
+      - name: Sync version from dispatch payload
+        uses: ./.github/actions/sync-version-from-dispatch
+        with:
+          release_tag: ${{ github.event.client_payload.release_tag }}
       - name: Build wheel
         uses: PyO3/maturin-action@v1
         with: