diff --git a/.github/workflows/claude-code-review.yml b/.github/workflows/claude-code-review.yml
index 25f4ad18..740a5aaf 100644
--- a/.github/workflows/claude-code-review.yml
+++ b/.github/workflows/claude-code-review.yml
@@ -12,16 +12,13 @@ on:
 
 jobs:
   claude-review:
-    # Optional: Filter by PR author
-    # if: |
-    #   github.event.pull_request.user.login == 'external-contributor' ||
-    #   github.event.pull_request.user.login == 'new-developer' ||
-    #   github.event.pull_request.author_association == 'FIRST_TIME_CONTRIBUTOR'
+    # fork からの PR では実行しない（secrets が渡らず失敗するため）
+    if: github.event.pull_request.head.repo.full_name == github.repository
 
     runs-on: ubuntu-latest
     permissions:
       contents: read
-      pull-requests: read
+      pull-requests: write # レビュー結果を PR にコメントするために必要
       issues: read
       id-token: write
 
diff --git a/.github/workflows/claude.yml b/.github/workflows/claude.yml
index eb9719ec..13039116 100644
--- a/.github/workflows/claude.yml
+++ b/.github/workflows/claude.yml
@@ -11,7 +11,9 @@ on:
     types: [submitted]
 
 jobs:
-  claude:
+  # @claude を書いた本人がこのリポジトリへの書込権限を持つかを先に確認する。
+  # claude ジョブは書込権限を持つため、第三者のコメントで起動させない。
+  authorize:
     if: |
       (github.event_name == 'issue_comment' && contains(github.event.comment.body, '@claude')) ||
       (github.event_name == 'pull_request_review_comment' && contains(github.event.comment.body, '@claude')) ||
@@ -20,10 +22,39 @@ jobs:
     runs-on: ubuntu-latest
     permissions:
       contents: read
-      pull-requests: read
-      issues: read
+    outputs:
+      trusted: ${{ steps.permission.outputs.trusted }}
+    steps:
+      - name: Check actor repository permission
+        id: permission
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REPOSITORY: ${{ github.repository }}
+          ACTOR: ${{ github.actor }}
+        run: |
+          set -euo pipefail
+
+          permission=$(gh api "repos/${REPOSITORY}/collaborators/${ACTOR}/permission" --jq '.permission' 2>/dev/null || echo none)
+
+          case "$permission" in
+            admin|maintain|write)
+              echo "trusted=true" >> "$GITHUB_OUTPUT"
+              ;;
+            *)
+              echo "trusted=false" >> "$GITHUB_OUTPUT"
+              ;;
+          esac
+
+  claude:
+    needs: authorize
+    if: needs.authorize.outputs.trusted == 'true'
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write # ブランチ作成・push に必要
+      pull-requests: write # PR の作成・コメント投稿に必要
+      issues: write # Issue へのコメント投稿に必要
       id-token: write
-      actions: read # Required for Claude to read CI results on PRs
+      actions: read # PR の CI 結果を読むために必要
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
diff --git a/.github/workflows/claude.yml.disabled b/.github/workflows/claude.yml.disabled
deleted file mode 100644
index 28a9bedc..00000000
--- a/.github/workflows/claude.yml.disabled
+++ /dev/null
@@ -1,78 +0,0 @@
-name: Claude Code
-
-on:
-  issue_comment:
-    types: [created]
-  pull_request_review_comment:
-    types: [created]
-  issues:
-    types: [opened, assigned]
-  pull_request_review:
-    types: [submitted]
-
-jobs:
-  authorize:
-    if: |
-      (github.event_name == 'issue_comment' && contains(github.event.comment.body, '@claude')) ||
-      (github.event_name == 'pull_request_review_comment' && contains(github.event.comment.body, '@claude')) ||
-      (github.event_name == 'pull_request_review' && contains(github.event.review.body, '@claude')) ||
-      (github.event_name == 'issues' && (contains(github.event.issue.body, '@claude') || contains(github.event.issue.title, '@claude')))
-    runs-on: ubuntu-latest
-    permissions:
-      contents: read
-    outputs:
-      trusted: ${{ steps.permission.outputs.trusted }}
-    steps:
-      - name: Check actor repository permission
-        id: permission
-        env:
-          GH_TOKEN: ${{ github.token }}
-          REPOSITORY: ${{ github.repository }}
-          ACTOR: ${{ github.actor }}
-        run: |
-          set -euo pipefail
-
-          permission=$(gh api "repos/${REPOSITORY}/collaborators/${ACTOR}/permission" --jq '.permission' 2>/dev/null || echo none)
-
-          case "$permission" in
-            admin|maintain|write)
-              echo "trusted=true" >> "$GITHUB_OUTPUT"
-              ;;
-            *)
-              echo "trusted=false" >> "$GITHUB_OUTPUT"
-              ;;
-          esac
-
-  claude:
-    needs: authorize
-    if: needs.authorize.outputs.trusted == 'true'
-    runs-on: ubuntu-latest
-    permissions:
-      contents: read
-      pull-requests: read
-      issues: read
-      actions: read # Required for Claude to read CI results on PRs
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-        with:
-          fetch-depth: 1
-
-      - name: Run Claude Code
-        id: claude
-        uses: anthropics/claude-code-action@v1
-        with:
-          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
-
-          # This is an optional setting that allows Claude to read CI results on PRs
-          additional_permissions: |
-            actions: read
-
-          # Optional: Give a custom prompt to Claude. If this is not specified, Claude will perform the instructions specified in the comment that tagged it.
-          # prompt: 'Update the pull request description to include a summary of changes.'
-
-          # Optional: Add claude_args to customize behavior and configuration
-          # See https://github.com/anthropics/claude-code-action/blob/main/docs/usage.md
-          # or https://code.claude.com/docs/en/cli-reference for available options
-          # claude_args: '--allowed-tools Bash(gh pr:*)'
-