diff --git a/.github/actions/bump-version/action.yaml b/.github/actions/bump-version/action.yaml
index 33b56ec..7616045 100644
--- a/.github/actions/bump-version/action.yaml
+++ b/.github/actions/bump-version/action.yaml
@@ -83,6 +83,8 @@ runs:
         }
 
         resolve_release_line() {
+          local package_version
+
           if [[ -n "${INPUT_RELEASE_LINE}" ]]; then
             if ! validate_release_line "${INPUT_RELEASE_LINE}"; then
               echo "Invalid release_line input '${INPUT_RELEASE_LINE}'. Expected format: <major>.<minor>" >&2
@@ -102,16 +104,13 @@ runs:
             return 0
           fi
 
-          if [[ "${BRANCH}" == "develop" ]]; then
-            local package_version
-            package_version="$(read_package_version)"
-            if [[ "${package_version}" =~ ^([0-9]+)\.([0-9]+)\.[0-9]+([-.].*)?$ ]]; then
-              echo "${BASH_REMATCH[1]}.${BASH_REMATCH[2]}"
-              return 0
-            fi
+          package_version="$(read_package_version)"
+          if [[ "${package_version}" =~ ^([0-9]+)\.([0-9]+)\.[0-9]+([-.].*)?$ ]]; then
+            echo "${BASH_REMATCH[1]}.${BASH_REMATCH[2]}"
+            return 0
           fi
 
-          echo "Unable to determine release line for branch '${BRANCH}'. Use release/<major>.<minor>, run in a PR targeting such a branch, or provide inputs.release_line." >&2
+          echo "Unable to determine release line for branch '${BRANCH}'. Use release/<major>.<minor>, provide inputs.release_line, or ensure package.json contains a semantic version." >&2
           exit 1
         }
 
diff --git a/README.md b/README.md
index ac9f344..6be26bf 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ Creates or updates the version in `package.json`, commits it, creates a matching
 Inputs:
 
 - `node_version`: Node.js version to use. Default: `24`
-- `release_line`: optional release line for dev builds when it cannot be derived from the branch or PR target. Format: `<major>.<minor>`
+- `release_line`: optional release line for dev builds. Format: `<major>.<minor>`. Overrides branch, PR target, and `package.json`.
 - `gitea_token`: optional token used for checkout and push
 
 Branch and tag rules:
@@ -23,7 +23,7 @@ Dev release line resolution order:
 - `inputs.release_line`
 - current branch if it matches `release/<major>.<minor>`
 - PR target branch if it matches `release/<major>.<minor>`
-- on `develop`, fallback to `major.minor` from `package.json`
+- `major.minor` from `package.json`
 
 If no release line can be resolved for a dev build, the action fails intentionally.
 
@@ -39,6 +39,7 @@ Branch examples:
 
 - `release/2.4` -> next `v2.4.0-beta.N`
 - feature branch in a PR to `release/2.4` -> `v2.4.0-dev.<UTC_TIMESTAMP>`
+- feature branch outside a PR with `package.json` version `2.4.0` -> `v2.4.0-dev.<UTC_TIMESTAMP>`
 - feature branch outside a PR with `release_line: 2.4` -> `v2.4.0-dev.<UTC_TIMESTAMP>`
 
 Example: