diff --git a/apps/api/src/api/v1/drift.py b/apps/api/src/api/v1/drift.py
index 4775cf03..04920335 100644
--- a/apps/api/src/api/v1/drift.py
+++ b/apps/api/src/api/v1/drift.py
@@ -48,7 +48,6 @@ async def trigger_drift_scan(
     """
     detector = get_drift_detector()
     analyzer = get_drift_analyzer()
-    interpreter = get_drift_interpreter()
 
     all_items = []
     last_report: DriftReport | None = None
@@ -115,18 +114,22 @@ async def rollback_drift(report_id: str) -> dict:
     return result
 
 
-@router.post("/reports/{report_id}/adopt", summary="承認變更並更新 Git")
-async def adopt_drift(_report_id: str) -> dict:
+@router.post("/reports/{report_id}/adopt", summary="承認變更並建立 Git PR")
+async def adopt_drift(report_id: str) -> dict:
     """
-    承認 K8s 漂移，更新 Git 使其與實際狀態一致
+    承認 K8s 漂移，透過 Gitea PR API 將漂移寫回 Git
 
-    ⚠️ 2026-04-04 ogt: C2 首席架構師裁示 — 暫時停用（ADR-057 起草後再啟用）
-    API Pod 內執行 git add -A 有安全風險，改用 Gitea PR API 實作後才開放。
+    2026-04-05 Claude Code: ADR-057 實作 — 改用 Gitea PR API（不再 git push main）
+    流程: 建立 drift/adopt-* branch → commit YAML 注解 → 建立 PR → Telegram 通知 SRE
     """
-    raise HTTPException(
-        status_code=501,
-        detail="adopt() 端點暫停開放。ADR-057 起草後將改由 Gitea PR API 實作。",
-    )
+    report = _recent_reports.get(report_id)
+    if not report:
+        raise HTTPException(status_code=404, detail=f"Report {report_id} not found")
+
+    from src.services.drift_adopt_service import get_drift_adopt_service
+    adopt_svc = get_drift_adopt_service()
+    result = await adopt_svc.adopt(report)
+    return result
 
 
 # =============================================================================
diff --git a/apps/api/src/core/config.py b/apps/api/src/core/config.py
index 318766b2..15c8ce29 100644
--- a/apps/api/src/core/config.py
+++ b/apps/api/src/core/config.py
@@ -97,6 +97,20 @@ class Settings(BaseSettings):
         description="Phase 25 P0: FORCE_LOCAL DIAGNOSE Ollama timeout (秒)，實測 ~173s，200s 含 buffer",
     )
 
+    # ==========================================================================
+    # Gitea — ADR-057 adopt() Gitea PR API (2026-04-05)
+    # ==========================================================================
+    GITEA_API_URL: str = Field(
+        default="http://192.168.0.110:3001",
+        description="Gitea 內網 API base URL",
+    )
+    GITEA_API_TOKEN: str = Field(
+        default="",
+        description="Gitea API Token（需 write:repository scope），ADR-057 adopt() 使用",
+    )
+    GITEA_REPO_OWNER: str = Field(default="wooo", description="Gitea repo owner")
+    GITEA_REPO_NAME: str = Field(default="awoooi", description="Gitea repo name")
+
     # ==========================================================================
     # CORS - 嚴格白名單 (無 UAT, 無 wildcard)
     # ==========================================================================
diff --git a/apps/api/src/services/drift_adopt_service.py b/apps/api/src/services/drift_adopt_service.py
new file mode 100644
index 00000000..26fd8c9b
--- /dev/null
+++ b/apps/api/src/services/drift_adopt_service.py
@@ -0,0 +1,317 @@
+"""
+Drift Adopt Service — ADR-057: Gitea PR API 實作
+=================================================
+職責：將合法漂移反向寫回 Git，透過 Gitea PR API 而非直接 git push
+
+設計邊界（核心原則）：
+- 不直接操作 git（不 git add/commit/push）
+- 透過 Gitea REST API 建立 branch + commit + PR
+- PR 需 SRE 手動 review 後 merge（不自動 merge main）
+- 只修改漂移相關的 YAML 欄位（不 add -A）
+
+流程：
+  adopt() 被呼叫
+    → 讀取 k8s/ 目錄對應 YAML 檔
+    → 建立 drift/adopt-{report_id[:8]}-{ts} branch
+    → 透過 Gitea API commit YAML 更新
+    → 建立 PR + 推送 Telegram 通知
+
+版本: v1.0
+建立: 2026-04-05 (台北時區)
+建立者: Claude Code (ADR-057 實作)
+關聯 ADR: ADR-057
+"""
+
+from __future__ import annotations
+
+import base64
+import pathlib
+from typing import TYPE_CHECKING
+
+import httpx
+import structlog
+
+from src.core.config import get_settings
+from src.utils.timezone import now_taipei
+
+if TYPE_CHECKING:
+    from src.models.drift import DriftReport
+
+logger = structlog.get_logger(__name__)
+
+
+class DriftAdoptService:
+    """
+    透過 Gitea PR API 將漂移寫回 Git
+
+    ADR-057 安全設計：
+    ✅ 使用 Gitea API（不在 API Pod 內執行 git）
+    ✅ 建立 PR 讓 SRE review（不直接 push main）
+    ✅ 只 commit k8s/ 目錄的 YAML（不 git add -A）
+    ✅ API Token 從 K8s Secret 注入（不寫死）
+    """
+
+    def __init__(self) -> None:
+        settings = get_settings()
+        self._api_url = settings.GITEA_API_URL.rstrip("/")
+        self._token = settings.GITEA_API_TOKEN
+        self._owner = settings.GITEA_REPO_OWNER
+        self._repo = settings.GITEA_REPO_NAME
+        self._k8s_dir = pathlib.Path("k8s")
+
+    async def adopt(self, report: "DriftReport", field_description: str = "") -> dict:
+        """
+        將漂移寫回 Git：建立 branch + commit + PR
+
+        Args:
+            report: 漂移報告（含具體 drift items）
+            field_description: 漂移欄位說明（用於 PR title）
+
+        Returns:
+            {"success": bool, "pr_url": str, "message": str}
+        """
+        if not self._token:
+            return {
+                "success": False,
+                "message": "GITEA_API_TOKEN 未設定，請在 K8s Secret 中新增此 key",
+                "pr_url": None,
+            }
+
+        ts = now_taipei().strftime("%Y%m%d%H%M%S")
+        branch_name = f"drift/adopt-{report.report_id[:8]}-{ts}"
+        pr_title = f"chore: adopt drift — {report.namespace} {field_description or report.summary}"
+
+        logger.info(
+            "drift_adopt_start",
+            report_id=report.report_id,
+            branch=branch_name,
+        )
+
+        try:
+            async with httpx.AsyncClient(timeout=30.0) as client:
+                headers = {
+                    "Authorization": f"token {self._token}",
+                    "Content-Type": "application/json",
+                }
+
+                # Step 1: 取得 main branch 的最新 SHA
+                main_sha = await self._get_main_sha(client, headers)
+                if not main_sha:
+                    return {"success": False, "message": "無法取得 main branch SHA", "pr_url": None}
+
+                # Step 2: 建立新 branch
+                branch_ok = await self._create_branch(client, headers, branch_name, main_sha)
+                if not branch_ok:
+                    return {"success": False, "message": f"建立 branch {branch_name} 失敗", "pr_url": None}
+
+                # Step 3: 找出受影響的 YAML 檔並 commit 更新
+                committed_files = await self._commit_drift_yaml(client, headers, branch_name, report)
+
+                # Step 4: 建立 PR
+                pr_url = await self._create_pr(
+                    client, headers, branch_name, pr_title, report, committed_files
+                )
+                if not pr_url:
+                    return {"success": False, "message": "建立 PR 失敗", "pr_url": None}
+
+                # Step 5: 推送 Telegram 通知
+                await self._notify_telegram(pr_url, report, pr_title)
+
+                logger.info("drift_adopt_pr_created", report_id=report.report_id, pr_url=pr_url)
+                return {
+                    "success": True,
+                    "message": f"PR 已建立，請 SRE review 後 merge",
+                    "pr_url": pr_url,
+                }
+
+        except Exception as e:
+            logger.error("drift_adopt_failed", report_id=report.report_id, error=str(e))
+            return {"success": False, "message": f"adopt 失敗: {str(e)}", "pr_url": None}
+
+    # =========================================================================
+    # Private helpers
+    # =========================================================================
+
+    async def _get_main_sha(self, client: httpx.AsyncClient, headers: dict) -> str | None:
+        """取得 main branch 最新 commit SHA"""
+        resp = await client.get(
+            f"{self._api_url}/api/v1/repos/{self._owner}/{self._repo}/branches/main",
+            headers=headers,
+        )
+        if resp.status_code == 200:
+            return resp.json()["commit"]["id"]
+        logger.error("drift_adopt_get_main_sha_failed", status=resp.status_code)
+        return None
+
+    async def _create_branch(
+        self, client: httpx.AsyncClient, headers: dict, branch_name: str, main_sha: str
+    ) -> bool:
+        """建立新 branch"""
+        resp = await client.post(
+            f"{self._api_url}/api/v1/repos/{self._owner}/{self._repo}/branches",
+            headers=headers,
+            json={"new_branch_name": branch_name, "old_branch_name": "main"},
+        )
+        if resp.status_code in (200, 201):
+            return True
+        logger.error("drift_adopt_create_branch_failed", status=resp.status_code, body=resp.text[:200])
+        return False
+
+    async def _commit_drift_yaml(
+        self, client: httpx.AsyncClient, headers: dict, branch_name: str, report: "DriftReport"
+    ) -> list[str]:
+        """
+        找出受漂移影響的 YAML 檔，更新實際值後 commit 到 branch
+
+        目前策略：標記 YAML 檔為「已承認漂移」（加注解），
+        等 ADR-057 Phase 2 再實作精確 YAML patch 邏輯。
+        """
+        committed = []
+        affected_kinds = {
+            item.resource_kind.lower()
+            for item in report.items
+            if not item.is_allowlisted
+        }
+
+        for yaml_file in sorted(self._k8s_dir.glob("*.yaml")):
+            # 判斷此 YAML 是否與漂移相關
+            file_stem = yaml_file.stem.lower()
+            if not any(kind in file_stem for kind in affected_kinds):
+                continue
+
+            try:
+                content = yaml_file.read_text()
+
+                # 取得 Gitea 上的 file SHA（用於 update API）
+                file_sha = await self._get_file_sha(client, headers, str(yaml_file))
+
+                # 在檔案末尾加入漂移承認注解
+                from src.utils.timezone import now_taipei as _now
+                ts_str = _now().strftime("%Y-%m-%d %H:%M:%S +0800")
+                annotation = (
+                    f"\n# [drift-adopted] {ts_str}\n"
+                    f"# Report: {report.report_id}\n"
+                    f"# Namespace: {report.namespace}\n"
+                    f"# Summary: {report.summary}\n"
+                )
+                updated_content = content + annotation
+                encoded = base64.b64encode(updated_content.encode()).decode()
+
+                # Commit 到 branch
+                payload = {
+                    "message": f"chore(drift): adopt {report.namespace} drift — {yaml_file.name}",
+                    "content": encoded,
+                    "branch": branch_name,
+                }
+                if file_sha:
+                    payload["sha"] = file_sha
+
+                url = f"{self._api_url}/api/v1/repos/{self._owner}/{self._repo}/contents/{yaml_file}"
+                resp = await client.put(url, headers=headers, json=payload)
+                if resp.status_code in (200, 201):
+                    committed.append(str(yaml_file))
+                    logger.info("drift_adopt_file_committed", file=str(yaml_file))
+                else:
+                    logger.warning("drift_adopt_file_commit_failed", file=str(yaml_file), status=resp.status_code)
+
+            except Exception as e:
+                logger.warning("drift_adopt_file_error", file=str(yaml_file), error=str(e))
+
+        return committed
+
+    async def _get_file_sha(
+        self, client: httpx.AsyncClient, headers: dict, file_path: str
+    ) -> str | None:
+        """取得 Gitea 上檔案的 SHA（update 時需要）"""
+        resp = await client.get(
+            f"{self._api_url}/api/v1/repos/{self._owner}/{self._repo}/contents/{file_path}",
+            headers=headers,
+            params={"ref": "main"},
+        )
+        if resp.status_code == 200:
+            return resp.json().get("sha")
+        return None
+
+    async def _create_pr(
+        self,
+        client: httpx.AsyncClient,
+        headers: dict,
+        branch_name: str,
+        pr_title: str,
+        report: "DriftReport",
+        committed_files: list[str],
+    ) -> str | None:
+        """建立 Pull Request，回傳 PR URL"""
+        files_md = "\n".join(f"- `{f}`" for f in committed_files) if committed_files else "（無直接匹配的 YAML 檔）"
+
+        intent_label = "❓ 意圖不明"
+        if report.interpretation:
+            intent_map = {
+                "emergency_hotfix": "🚨 緊急 Hotfix",
+                "human_error": "⚠️ 人為誤操作",
+                "automated_change": "🤖 系統自動變更",
+                "unknown": "❓ 意圖不明",
+            }
+            intent_label = intent_map.get(report.interpretation.intent.value, "❓ 意圖不明")
+
+        body = (
+            f"## Config Drift 承認\n\n"
+            f"**Report ID**: `{report.report_id}`\n"
+            f"**Namespace**: `{report.namespace}`\n"
+            f"**漂移摘要**: {report.summary}\n"
+            f"**Nemotron 意圖**: {intent_label}\n"
+            f"{f'**說明**: {report.interpretation.explanation}' if report.interpretation else ''}\n\n"
+            f"## 異動檔案\n\n{files_md}\n\n"
+            f"## 說明\n\n"
+            f"此 PR 由 AWOOOI Config Drift Detection 系統自動建立。\n"
+            f"承認此次 K8s 漂移為合法變更，將漂移狀態寫回 Git。\n\n"
+            f"> **SRE 確認事項**:\n"
+            f"> - [ ] 確認漂移是預期的合法變更\n"
+            f"> - [ ] 確認 YAML 注解正確反映變更意圖\n"
+            f"> - [ ] merge 後手動更新 K8s YAML 的實際差異值\n"
+        )
+
+        resp = await client.post(
+            f"{self._api_url}/api/v1/repos/{self._owner}/{self._repo}/pulls",
+            headers=headers,
+            json={
+                "title": pr_title,
+                "body": body,
+                "head": branch_name,
+                "base": "main",
+            },
+        )
+        if resp.status_code in (200, 201):
+            pr_data = resp.json()
+            return pr_data.get("html_url") or pr_data.get("url")
+        logger.error("drift_adopt_create_pr_failed", status=resp.status_code, body=resp.text[:300])
+        return None
+
+    async def _notify_telegram(self, pr_url: str, report: "DriftReport", pr_title: str) -> None:
+        """推送 Telegram 通知 SRE"""
+        try:
+            from src.services.telegram_gateway import get_telegram_gateway
+            tg = get_telegram_gateway()
+            await tg.send_text(
+                f"📋 <b>Config Drift 承認 PR 已建立</b>\n"
+                f"Namespace: {report.namespace}\n"
+                f"漂移: {report.summary}\n\n"
+                f"PR: {pr_url}\n\n"
+                f"請 SRE review 後 merge。"
+            )
+        except Exception as e:
+            logger.warning("drift_adopt_telegram_failed", error=str(e))
+
+
+# =============================================================================
+# Singleton
+# =============================================================================
+
+_adopt_service: DriftAdoptService | None = None
+
+
+def get_drift_adopt_service() -> DriftAdoptService:
+    global _adopt_service
+    if _adopt_service is None:
+        _adopt_service = DriftAdoptService()
+    return _adopt_service