diff --git a/README.md b/README.md
index 6f29e4a..52c8183 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 A forge-neutral composite action for preparing a versioned Frappe/ERPNext app before merging its release branch. It uses [`bump-my-version`](https://callowayproject.github.io/bump-my-version/) and ordinary Git commands, without `gh` or GitHub API calls.
 
-The action compares `[tool.bumpversion].current_version` on the checked-out target branch with the configured base branch:
+The action compares the app's `__version__` on the checked-out target branch with the configured base branch:
 
 - Equal: bump, commit, and optionally push the new version.
 - Target newer than base: do nothing, making PR synchronization events idempotent.
@@ -13,22 +13,9 @@ The action compares `[tool.bumpversion].current_version` on the checked-out targ
 - A Linux runner with Bash, Git, and Python 3.11 or newer.
 - A clean checkout of the branch that should receive the version commit.
 - Persisted Git credentials with permission to push that branch.
-- Stable `MAJOR.MINOR.PATCH` versions.
-- A `bump-my-version` configuration that includes every version file.
+- A version file containing a stable `MAJOR.MINOR.PATCH` assignment such as `__version__ = "0.0.1"`.
 
-Example `pyproject.toml` for a Frappe app:
-
-```toml
-[tool.bumpversion]
-current_version = "0.0.1"
-commit = false
-tag = false
-
-[[tool.bumpversion.files]]
-filename = "erp_operations/__init__.py"
-search = '__version__ = "{current_version}"'
-replace = '__version__ = "{new_version}"'
-```
+No `bump-my-version` configuration is required in the consuming app. The action passes the current version, search/replace templates, and version file directly to the CLI.
 
 ## Gitea Actions usage
 
@@ -61,7 +48,6 @@ jobs:
         # The absolute URL is required when Gitea's DEFAULT_ACTIONS_URL is "github".
         uses: https://gitea.cptckp.com/Nurinda/bump-erp-app-version@v1
         with:
-          config-file: pyproject.toml
           version-file: erp_operations/__init__.py
           base-branch: main
           target-branch: develop
@@ -79,8 +65,7 @@ Gitea may suppress workflows caused by pushes authenticated with its built-in `G
 
 | Input | Default | Description |
 |---|---|---|
-| `config-file` | `pyproject.toml` | `bump-my-version` TOML configuration |
-| `version-file` | empty | App `__init__.py` used to bootstrap a base branch that predates the configuration |
+| `version-file` | required | App `__init__.py` containing the authoritative `__version__` |
 | `base-branch` | `main` | Branch providing the baseline version |
 | `target-branch` | `develop` | Checked-out branch receiving the commit |
 | `bump` | `patch` | `major`, `minor`, or `patch` |
@@ -104,7 +89,7 @@ Gitea may suppress workflows caused by pushes authenticated with its built-in `G
 
 The action does not force-push, create tags, publish releases, or call forge APIs. Concurrent release jobs are resolved safely by the remote rejecting a non-fast-forward push. Configure workflow-level concurrency if release PRs can overlap.
 
-For the first versioned release, the base branch might not contain `[tool.bumpversion]` yet. Set `version-file` to the app's `__init__.py`; the action will read its base-branch `__version__` as the bootstrap baseline. Once the configuration reaches the base branch, it becomes the authoritative baseline.
+The configured `version-file` is the only version source. The action reads it from both branches and commits only the version change produced by `bump-my-version`.
 
 ## Releasing the action
 
diff --git a/action.yml b/action.yml
index 1cd380f..192e874 100644
--- a/action.yml
+++ b/action.yml
@@ -1,14 +1,9 @@
 name: Bump ERP app version
 description: Bump a Frappe/ERPNext app version on a release branch using bump-my-version
 inputs:
-  config-file:
-    description: Path to the bump-my-version TOML configuration
-    required: false
-    default: pyproject.toml
   version-file:
-    description: App __init__.py used to bootstrap when the base branch has no bump-my-version config
-    required: false
-    default: ""
+    description: App __init__.py containing a stable MAJOR.MINOR.PATCH __version__ assignment
+    required: true
   base-branch:
     description: Branch whose version is used as the release baseline
     required: false
@@ -65,7 +60,6 @@ runs:
       id: bump
       shell: bash
       env:
-        INPUT_CONFIG_FILE: ${{ inputs.config-file }}
         INPUT_VERSION_FILE: ${{ inputs.version-file }}
         INPUT_BASE_BRANCH: ${{ inputs.base-branch }}
         INPUT_TARGET_BRANCH: ${{ inputs.target-branch }}
diff --git a/scripts/bump.sh b/scripts/bump.sh
index 1c3d495..e6fbff0 100755
--- a/scripts/bump.sh
+++ b/scripts/bump.sh
@@ -1,8 +1,7 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
-: "${INPUT_CONFIG_FILE:?config-file is required}"
-: "${INPUT_VERSION_FILE:=}"
+: "${INPUT_VERSION_FILE:?version-file is required}"
 : "${INPUT_BASE_BRANCH:?base-branch is required}"
 : "${INPUT_TARGET_BRANCH:?target-branch is required}"
 : "${INPUT_BUMP:?bump is required}"
@@ -24,8 +23,8 @@ case "${INPUT_BUMP}" in
 	*) echo "bump must be major, minor, or patch" >&2; exit 1 ;;
 esac
 
-if [[ ! -f "${INPUT_CONFIG_FILE}" ]]; then
-	echo "Configuration file not found: ${INPUT_CONFIG_FILE}" >&2
+if [[ ! -f "${INPUT_VERSION_FILE}" ]]; then
+	echo "Version file not found: ${INPUT_VERSION_FILE}" >&2
 	exit 1
 fi
 
@@ -45,12 +44,8 @@ git fetch "${INPUT_REMOTE}" \
 
 script_dir=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)
 base_ref="refs/remotes/${INPUT_REMOTE}/${INPUT_BASE_BRANCH}"
-current_version=$(python3 "${script_dir}/read_version.py" "${INPUT_CONFIG_FILE}")
-base_version_args=("${INPUT_CONFIG_FILE}" --ref "${base_ref}")
-if [[ -n "${INPUT_VERSION_FILE}" ]]; then
-	base_version_args+=(--fallback-version-file "${INPUT_VERSION_FILE}")
-fi
-base_version=$(python3 "${script_dir}/read_version.py" "${base_version_args[@]}")
+current_version=$(python3 "${script_dir}/read_version.py" "${INPUT_VERSION_FILE}")
+base_version=$(python3 "${script_dir}/read_version.py" "${INPUT_VERSION_FILE}" --ref "${base_ref}")
 
 comparison=$(python3 - "${current_version}" "${base_version}" <<'PY'
 import re
@@ -96,13 +91,17 @@ git config user.email "${INPUT_GIT_USER_EMAIL}"
 
 message=${INPUT_COMMIT_MESSAGE//\{version\}/\{new_version\}}
 "${venv_dir}/bin/bump-my-version" bump \
-	--config-file "${INPUT_CONFIG_FILE}" \
+	--current-version "${current_version}" \
+	--search '__version__ = "{current_version}"' \
+	--replace '__version__ = "{new_version}"' \
+	--no-configured-files \
 	--commit \
 	--no-tag \
 	--message "${message}" \
-	"${INPUT_BUMP}"
+	"${INPUT_BUMP}" \
+	"${INPUT_VERSION_FILE}"
 
-new_version=$(python3 "${script_dir}/read_version.py" "${INPUT_CONFIG_FILE}")
+new_version=$(python3 "${script_dir}/read_version.py" "${INPUT_VERSION_FILE}")
 commit=$(git rev-parse HEAD)
 
 if [[ "${INPUT_PUSH}" == "true" ]]; then
diff --git a/scripts/read_version.py b/scripts/read_version.py
index ce0383d..7ee6f81 100755
--- a/scripts/read_version.py
+++ b/scripts/read_version.py
@@ -1,73 +1,40 @@
 #!/usr/bin/env python3
-"""Read bump-my-version's current_version from a local file or Git ref."""
+"""Read a Frappe app's stable __version__ from a local file or Git ref."""
 
 from __future__ import annotations
 
 import argparse
 import re
 import subprocess
-import sys
-import tomllib
 
 
 def parse_args() -> argparse.Namespace:
 	parser = argparse.ArgumentParser()
-	parser.add_argument("config_file")
+	parser.add_argument("version_file")
 	parser.add_argument("--ref")
-	parser.add_argument("--fallback-version-file")
 	return parser.parse_args()
 
 
-def read_bootstrap_version(args: argparse.Namespace, config_error: KeyError) -> str:
-	if not args.ref or not args.fallback_version_file:
-		raise SystemExit(
-			f"Could not read tool.bumpversion.current_version from {args.config_file}: {config_error}"
-		) from config_error
-
-	try:
-		version_content = subprocess.check_output(
-			["git", "show", f"{args.ref}:{args.fallback_version_file}"],
-			text=True,
-		)
-	except (OSError, subprocess.CalledProcessError) as error:
-		raise SystemExit(
-			f"Could not load bootstrap version file {args.fallback_version_file}: {error}"
-		) from error
-
-	match = re.search(r'^__version__ = "(\d+\.\d+\.\d+)"$', version_content, re.MULTILINE)
-	if not match:
-		raise SystemExit(f"Could not read __version__ from bootstrap file {args.fallback_version_file}")
-
-	version = match.group(1)
-	print(f"Using bootstrap version {version} from {args.fallback_version_file}", file=sys.stderr)
-	return version
-
-
 def main() -> None:
 	args = parse_args()
 	try:
 		if args.ref:
 			content = subprocess.check_output(
-				["git", "show", f"{args.ref}:{args.config_file}"],
+				["git", "show", f"{args.ref}:{args.version_file}"],
+				text=True,
 			)
 		else:
-			with open(args.config_file, "rb") as config_file:
-				content = config_file.read()
+			with open(args.version_file, encoding="utf-8") as version_file:
+				content = version_file.read()
 	except (OSError, subprocess.CalledProcessError) as error:
-		raise SystemExit(f"Could not load {args.config_file}: {error}") from error
+		raise SystemExit(f"Could not load {args.version_file}: {error}") from error
 
-	try:
-		version = tomllib.loads(content.decode())["tool"]["bumpversion"]["current_version"]
-	except KeyError as error:
-		version = read_bootstrap_version(args, error)
-	except (TypeError, UnicodeDecodeError, tomllib.TOMLDecodeError) as error:
+	match = re.search(r'^__version__ = "(\d+\.\d+\.\d+)"$', content, re.MULTILINE)
+	if not match:
 		raise SystemExit(
-			f"Could not read tool.bumpversion.current_version from {args.config_file}: {error}"
-		) from error
-
-	if not isinstance(version, str):
-		raise SystemExit("tool.bumpversion.current_version must be a string")
-	print(version)
+			f"Could not read a stable MAJOR.MINOR.PATCH __version__ from {args.version_file}"
+		)
+	print(match.group(1))
 
 
 if __name__ == "__main__":
diff --git a/tests/integration.sh b/tests/integration.sh
index 85399b9..c4b933d 100755
--- a/tests/integration.sh
+++ b/tests/integration.sh
@@ -22,23 +22,8 @@ git commit -qm initial
 git remote add origin "${test_root}/remote.git"
 git push -qu origin main
 git switch -qc develop
-cat >> pyproject.toml <<'TOML'
-
-[tool.bumpversion]
-current_version = "0.0.1"
-commit = false
-tag = false
-
-[[tool.bumpversion.files]]
-filename = "erp_operations/__init__.py"
-search = '__version__ = "{current_version}"'
-replace = '__version__ = "{new_version}"'
-TOML
-git add pyproject.toml
-git commit -qm 'configure versioning'
 git push -qu origin develop
 
-export INPUT_CONFIG_FILE=pyproject.toml
 export INPUT_VERSION_FILE=erp_operations/__init__.py
 export INPUT_BASE_BRANCH=main
 export INPUT_TARGET_BRANCH=develop
@@ -53,7 +38,7 @@ export RUNNER_TEMP="${test_root}"
 export GITHUB_OUTPUT="${test_root}/output"
 
 "${repo_root}/scripts/bump.sh"
-grep -q '^current_version = "0.0.2"$' pyproject.toml
+! grep -q '^\[tool.bumpversion\]' pyproject.toml
 grep -q '^__version__ = "0.0.2"$' erp_operations/__init__.py
 grep -q '^bumped=true$' "${GITHUB_OUTPUT}"
 grep -q '^previous-version=0.0.1$' "${GITHUB_OUTPUT}"