diff --git a/backend/app/core/app_config.py b/backend/app/core/app_config.py
index bd7b462..1b6faa5 100644
--- a/backend/app/core/app_config.py
+++ b/backend/app/core/app_config.py
@@ -1,21 +1,25 @@
 """
 Per-service runtime config helpers.
 
-Config files live on the shared `app_config` Docker volume at /config/.
-Each service has its own JSON file.
+All config files are stored in the 'config' bucket of the storage-service.
+Every function is async — callers must await them.
 
-Atomic write pattern: write to .tmp in same dir, then os.replace() so
-services never read a partial file.
+Key layout in the config bucket:
+  ai_service_config.json
+  doc_service_config.json
+  appearance_config.json
+  themes/{id}.json
 """
 import copy
-import json
-import os
+import logging
 import re
-from pathlib import Path
+from copy import deepcopy
 
 from pydantic import BaseModel
 
-_CONFIG_DIR = Path(os.environ.get("APP_CONFIG_DIR", "/config"))
+from app.core import config_storage
+
+logger = logging.getLogger(__name__)
 
 # ── AI service config schemas ──────────────────────────────────────────────────
 
@@ -108,59 +112,50 @@ def _mask_ai_config(data: dict) -> dict:
 
 # ── Load / Save ────────────────────────────────────────────────────────────────
 
-def _config_path(service: str) -> Path:
-    return _CONFIG_DIR / f"{service}_config.json"
-
-
-def load_service_config(service: str) -> dict:
-    path = _config_path(service)
-    if not path.exists():
+async def load_service_config(service: str) -> dict:
+    data = await config_storage.read_json(f"{service}_config.json")
+    if data is None:
         if service == "ai_service":
             return AIServiceConfig().model_dump()
         if service == "doc_service":
             return DocServiceConfig().model_dump()
         return {}
-    with path.open() as f:
-        return json.load(f)
+    return data
 
 
-def save_service_config(service: str, data: dict) -> None:
-    path = _config_path(service)
-    path.parent.mkdir(parents=True, exist_ok=True)
-    tmp = path.with_suffix(".tmp")
-    tmp.write_text(json.dumps(data, indent=2))
-    os.replace(tmp, path)
+async def save_service_config(service: str, data: dict) -> None:
+    await config_storage.write_json(f"{service}_config.json", data)
 
 
 # AI service helpers
 
-def load_ai_service_config() -> AIServiceConfig:
-    raw = load_service_config("ai_service")
+async def load_ai_service_config() -> AIServiceConfig:
+    raw = await load_service_config("ai_service")
     return AIServiceConfig.model_validate(raw)
 
 
-def save_ai_service_config(config: AIServiceConfig) -> None:
-    save_service_config("ai_service", config.model_dump())
+async def save_ai_service_config(config: AIServiceConfig) -> None:
+    await save_service_config("ai_service", config.model_dump())
 
 
-def load_ai_service_config_masked() -> dict:
-    raw = load_service_config("ai_service")
+async def load_ai_service_config_masked() -> dict:
+    raw = await load_service_config("ai_service")
     return _mask_ai_config(raw)
 
 
 # Doc service helpers
 
-def load_doc_service_config() -> DocServiceConfig:
-    raw = load_service_config("doc_service")
+async def load_doc_service_config() -> DocServiceConfig:
+    raw = await load_service_config("doc_service")
     return DocServiceConfig.model_validate(raw)
 
 
-def save_doc_service_config(config: DocServiceConfig) -> None:
-    save_service_config("doc_service", config.model_dump())
+async def save_doc_service_config(config: DocServiceConfig) -> None:
+    await save_service_config("doc_service", config.model_dump())
 
 
-def load_doc_service_config_masked() -> dict:
-    return load_service_config("doc_service")
+async def load_doc_service_config_masked() -> dict:
+    return await load_service_config("doc_service")
 
 
 def _merge_api_key(new_key: str, existing_key: str) -> str:
@@ -172,18 +167,16 @@ def _merge_api_key(new_key: str, existing_key: str) -> str:
 
 # ── System prompts helpers ─────────────────────────────────────────────────────
 
-# Registry of all services that have editable system prompts.
-# key = service identifier, value = human-readable label
 SYSTEM_PROMPT_SERVICES: dict[str, str] = {
     "doc_service": "Document Service",
 }
 
 
-def load_all_system_prompts() -> dict:
+async def load_all_system_prompts() -> dict:
     """Return {service_id: {label, system, user_template, default_system, default_user_template}}."""
     result: dict = {}
     for service_id, label in SYSTEM_PROMPT_SERVICES.items():
-        config = load_service_config(service_id)
+        config = await load_service_config(service_id)
         prompts = config.get("system_prompts", {})
         defaults = _get_service_prompt_defaults(service_id)
         result[service_id] = {
@@ -196,15 +189,14 @@ def load_all_system_prompts() -> dict:
     return result
 
 
-def save_service_system_prompts(service_id: str, system: str, user_template: str) -> None:
-    """Persist updated system prompts into the service's config file."""
+async def save_service_system_prompts(service_id: str, system: str, user_template: str) -> None:
     if service_id not in SYSTEM_PROMPT_SERVICES:
         raise ValueError(f"Unknown service: {service_id!r}")
-    config = load_service_config(service_id)
+    config = await load_service_config(service_id)
     config.setdefault("system_prompts", {})
     config["system_prompts"]["system"] = system
     config["system_prompts"]["user_template"] = user_template
-    save_service_config(service_id, config)
+    await save_service_config(service_id, config)
 
 
 def _get_service_prompt_defaults(service_id: str) -> dict:
@@ -221,26 +213,19 @@ class AppearanceConfig(BaseModel):
     default_mode: str = "system"
 
 
-def load_appearance_config() -> AppearanceConfig:
-    path = _CONFIG_DIR / "appearance_config.json"
-    if not path.exists():
+async def load_appearance_config() -> AppearanceConfig:
+    data = await config_storage.read_json("appearance_config.json")
+    if data is None:
         return AppearanceConfig()
-    with path.open() as f:
-        return AppearanceConfig.model_validate(json.load(f))
+    return AppearanceConfig.model_validate(data)
 
 
-def save_appearance_config(config: AppearanceConfig) -> None:
-    path = _CONFIG_DIR / "appearance_config.json"
-    path.parent.mkdir(parents=True, exist_ok=True)
-    tmp = path.with_suffix(".tmp")
-    tmp.write_text(json.dumps(config.model_dump(), indent=2))
-    os.replace(tmp, path)
+async def save_appearance_config(config: AppearanceConfig) -> None:
+    await config_storage.write_json("appearance_config.json", config.model_dump())
 
 
 # ── Theme file management ──────────────────────────────────────────────────────
 
-_THEMES_DIR = _CONFIG_DIR / "themes"
-
 # 9 required colour tokens per mode
 _REQUIRED_TOKENS = frozenset({
     "primary", "primary_hover", "accent", "accent_hover",
@@ -361,36 +346,57 @@ _BUILTIN_THEMES: list[dict] = [
 ]
 
 
-def seed_builtin_themes() -> None:
-    """Create /config/themes/ and write built-in theme files if missing."""
-    _THEMES_DIR.mkdir(parents=True, exist_ok=True)
+async def seed_builtin_themes() -> None:
+    """Write built-in theme files to storage-service if they are not already there."""
+    existing_keys = await config_storage.list_keys(prefix="themes/")
+    existing_ids = {k.removeprefix("themes/").removesuffix(".json") for k in existing_keys}
     for theme in _BUILTIN_THEMES:
-        path = _THEMES_DIR / f"{theme['id']}.json"
-        if not path.exists():
-            path.write_text(json.dumps(theme, indent=2))
+        if theme["id"] not in existing_ids:
+            await config_storage.write_json(f"themes/{theme['id']}.json", theme)
+    logger.info("Built-in themes seeded (%d themes)", len(_BUILTIN_THEMES))
 
 
-def load_all_themes() -> list[dict]:
-    """Return all themes from /config/themes/*.json, built-ins first."""
-    if not _THEMES_DIR.exists():
-        seed_builtin_themes()
-    themes = []
-    for f in sorted(_THEMES_DIR.glob("*.json")):
-        try:
-            themes.append(json.loads(f.read_text()))
-        except (json.JSONDecodeError, OSError):
-            pass
-    # Sort: built-ins first (preserving their original order), then custom by label
+async def load_all_themes() -> list[dict]:
+    """Return all themes from storage-service, built-ins first then custom by label."""
+    keys = await config_storage.list_keys(prefix="themes/")
+    themes: list[dict] = []
+    for key in keys:
+        data = await config_storage.read_json(key)
+        if data:
+            themes.append(data)
+
     builtin_ids = [t["id"] for t in _BUILTIN_THEMES]
+
     def sort_key(t: dict) -> tuple:
         tid = t.get("id", "")
         try:
             return (0, builtin_ids.index(tid))
         except ValueError:
             return (1, t.get("label", tid).lower())
+
     return sorted(themes, key=sort_key)
 
 
+async def load_theme_by_id(theme_id: str) -> dict | None:
+    """Return a single theme dict, or None if not found."""
+    return await config_storage.read_json(f"themes/{theme_id}.json")
+
+
+async def save_theme(theme: dict) -> None:
+    """Write a theme to storage-service."""
+    await config_storage.write_json(f"themes/{theme['id']}.json", theme)
+
+
+async def delete_theme(theme_id: str) -> None:
+    """Delete a custom theme. Raises ValueError for built-ins, KeyError if not found."""
+    data = await config_storage.read_json(f"themes/{theme_id}.json")
+    if data is None:
+        raise FileNotFoundError(theme_id)
+    if data.get("builtin"):
+        raise ValueError("Cannot delete a built-in theme")
+    await config_storage.delete_key(f"themes/{theme_id}.json")
+
+
 def validate_theme_tokens(colors: dict) -> list[str]:
     """Return a list of validation error messages, empty if valid."""
     errors = []
@@ -401,23 +407,3 @@ def validate_theme_tokens(colors: dict) -> list[str]:
         if key in _REQUIRED_TOKENS and not _RGB_RE.match(str(val)):
             errors.append(f"Token '{key}' must be an RGB triplet like '37 99 235', got: {val!r}")
     return errors
-
-
-def save_theme(theme: dict) -> None:
-    """Write a theme file atomically."""
-    _THEMES_DIR.mkdir(parents=True, exist_ok=True)
-    path = _THEMES_DIR / f"{theme['id']}.json"
-    tmp = path.with_suffix(".tmp")
-    tmp.write_text(json.dumps(theme, indent=2))
-    os.replace(tmp, path)
-
-
-def delete_theme(theme_id: str) -> None:
-    """Delete a custom theme file. Raises ValueError for built-ins, FileNotFoundError if missing."""
-    path = _THEMES_DIR / f"{theme_id}.json"
-    if not path.exists():
-        raise FileNotFoundError(theme_id)
-    data = json.loads(path.read_text())
-    if data.get("builtin"):
-        raise ValueError("Cannot delete a built-in theme")
-    path.unlink()
diff --git a/backend/app/core/config_storage.py b/backend/app/core/config_storage.py
new file mode 100644
index 0000000..8a9b8e2
--- /dev/null
+++ b/backend/app/core/config_storage.py
@@ -0,0 +1,63 @@
+"""
+Async HTTP client for the 'config' bucket in storage-service.
+
+All JSON config files (AI settings, doc settings, appearance, themes, …) are stored
+in the 'config' bucket under the storage-service.  This module provides thin
+async helpers so app_config.py does not depend on the filesystem at all.
+"""
+import json
+import logging
+
+import httpx
+
+from app.core.config import settings
+
+logger = logging.getLogger(__name__)
+
+_BUCKET = "config"
+_TIMEOUT = 10.0
+
+
+def _url(key: str) -> str:
+    return f"{settings.STORAGE_SERVICE_URL}/objects/{_BUCKET}/{key}"
+
+
+async def read_json(key: str) -> dict | None:
+    """Return parsed JSON from the config bucket, or None if the key does not exist."""
+    async with httpx.AsyncClient(timeout=_TIMEOUT) as client:
+        resp = await client.get(_url(key))
+        if resp.status_code == 404:
+            return None
+        resp.raise_for_status()
+        return resp.json()
+
+
+async def write_json(key: str, data: dict) -> None:
+    """Serialise *data* to JSON and PUT it into the config bucket."""
+    payload = json.dumps(data, indent=2).encode()
+    async with httpx.AsyncClient(timeout=_TIMEOUT) as client:
+        resp = await client.put(
+            _url(key),
+            content=payload,
+            headers={"Content-Type": "application/octet-stream"},
+        )
+        resp.raise_for_status()
+
+
+async def delete_key(key: str) -> None:
+    """Delete a key from the config bucket.  No-op if it does not exist."""
+    async with httpx.AsyncClient(timeout=_TIMEOUT) as client:
+        resp = await client.delete(_url(key))
+        if resp.status_code not in (204, 404):
+            resp.raise_for_status()
+
+
+async def list_keys(prefix: str = "") -> list[str]:
+    """List all keys in the config bucket, optionally filtered by *prefix*."""
+    async with httpx.AsyncClient(timeout=_TIMEOUT) as client:
+        resp = await client.get(f"{settings.STORAGE_SERVICE_URL}/objects/{_BUCKET}")
+        resp.raise_for_status()
+        keys: list[str] = resp.json().get("keys", [])
+    if prefix:
+        keys = [k for k in keys if k.startswith(prefix)]
+    return keys
diff --git a/backend/app/main.py b/backend/app/main.py
index fb1239d..f6913a9 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -15,7 +15,7 @@ from app.services.service_health import check_all, health_check_loop, register_s
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
-    await asyncio.to_thread(seed_builtin_themes)
+    await seed_builtin_themes()
     register_services(
         doc_service_url=settings.DOC_SERVICE_URL,
         ai_service_url=settings.AI_SERVICE_URL,
diff --git a/backend/app/routers/settings.py b/backend/app/routers/settings.py
index b8b6bdc..069fe08 100644
--- a/backend/app/routers/settings.py
+++ b/backend/app/routers/settings.py
@@ -2,10 +2,9 @@
 Admin-only settings API for per-service runtime configuration.
 
 All endpoints require the caller to be an admin (Depends(get_current_admin)).
-Config files live on the shared app_config volume (/config/).
+Config files are stored in the 'config' bucket of storage-service.
 """
-import asyncio
-import json
+import re as _re
 
 import httpx
 from fastapi import APIRouter, Depends, HTTPException
@@ -21,10 +20,11 @@ from app.core.app_config import (
     load_all_system_prompts,
     load_all_themes,
     load_appearance_config,
-    save_appearance_config,
     load_doc_service_config,
     load_doc_service_config_masked,
+    load_theme_by_id,
     save_ai_service_config,
+    save_appearance_config,
     save_doc_service_config,
     save_service_system_prompts,
     save_theme,
@@ -36,6 +36,8 @@ from app.models.user import User
 
 router = APIRouter()
 
+_THEME_ID_RE = _re.compile(r"^[a-z0-9_-]{1,64}$")
+
 
 # ── Pydantic request bodies ────────────────────────────────────────────────────
 
@@ -98,7 +100,7 @@ class ThemeUpdate(BaseModel):
 async def get_ai_settings(
     _: User = Depends(get_service_admin("ai-service")),
 ) -> dict:
-    return load_ai_service_config_masked()
+    return await load_ai_service_config_masked()
 
 
 @router.patch("/ai")
@@ -110,7 +112,7 @@ async def update_ai_settings(
     if body.provider not in valid_providers:
         raise HTTPException(status_code=422, detail=f"provider must be one of {valid_providers}")
 
-    config = load_ai_service_config()
+    config = await load_ai_service_config()
     config.provider = body.provider
 
     # Anthropic
@@ -139,8 +141,8 @@ async def update_ai_settings(
             body.lmstudio_api_key, config.lmstudio.api_key
         )
 
-    await asyncio.to_thread(save_ai_service_config, config)
-    return load_ai_service_config_masked()
+    await save_ai_service_config(config)
+    return await load_ai_service_config_masked()
 
 
 @router.post("/ai/test")
@@ -173,7 +175,7 @@ async def test_ai_connection(
 async def get_documents_limits(
     _: User = Depends(get_service_admin("doc-service")),
 ) -> dict:
-    return load_doc_service_config_masked()
+    return await load_doc_service_config_masked()
 
 
 @router.patch("/documents/limits")
@@ -184,10 +186,10 @@ async def update_documents_limits(
     if body.max_pdf_mb < 1 or body.max_pdf_mb > 200:
         raise HTTPException(status_code=422, detail="max_pdf_mb must be between 1 and 200")
 
-    config = load_doc_service_config()
+    config = await load_doc_service_config()
     config.documents.max_pdf_bytes = body.max_pdf_mb * 1024 * 1024
-    await asyncio.to_thread(save_doc_service_config, config)
-    return load_doc_service_config_masked()
+    await save_doc_service_config(config)
+    return await load_doc_service_config_masked()
 
 
 # ── System prompts ─────────────────────────────────────────────────────────────
@@ -197,8 +199,7 @@ async def update_documents_limits(
 async def get_system_prompts(
     _: User = Depends(get_service_admin("ai-service")),
 ) -> dict:
-    """Return all editable system prompts, keyed by service id."""
-    return await asyncio.to_thread(load_all_system_prompts)
+    return await load_all_system_prompts()
 
 
 @router.patch("/system-prompts/{service_id}")
@@ -207,26 +208,20 @@ async def update_system_prompt(
     body: SystemPromptUpdate,
     _: User = Depends(get_service_admin("ai-service")),
 ) -> dict:
-    """Update the system prompts for a single service."""
     if service_id not in SYSTEM_PROMPT_SERVICES:
         raise HTTPException(status_code=404, detail=f"No system prompts registered for {service_id!r}")
-    await asyncio.to_thread(
-        save_service_system_prompts, service_id, body.system, body.user_template
-    )
-    return await asyncio.to_thread(load_all_system_prompts)
+    await save_service_system_prompts(service_id, body.system, body.user_template)
+    return await load_all_system_prompts()
 
 
 # ── Appearance (global default — auth read, admin write) ───────────────────────
 
-import re as _re
-_THEME_ID_RE = _re.compile(r"^[a-z0-9_-]{1,64}$")
-
 
 @router.get("/appearance")
 async def get_appearance(
     _: User = Depends(get_current_user),
 ) -> dict:
-    config = await asyncio.to_thread(load_appearance_config)
+    config = await load_appearance_config()
     return config.model_dump()
 
 
@@ -237,12 +232,12 @@ async def update_appearance(
 ) -> dict:
     if body.default_mode not in ("light", "dark", "system"):
         raise HTTPException(status_code=422, detail="default_mode must be 'light', 'dark', or 'system'")
-    themes = await asyncio.to_thread(load_all_themes)
+    themes = await load_all_themes()
     theme_ids = {t["id"] for t in themes}
     if body.theme not in theme_ids:
         raise HTTPException(status_code=422, detail=f"Unknown theme: {body.theme!r}")
     config = AppearanceConfig(theme=body.theme, default_mode=body.default_mode)
-    await asyncio.to_thread(save_appearance_config, config)
+    await save_appearance_config(config)
     return config.model_dump()
 
 
@@ -253,7 +248,7 @@ async def update_appearance(
 async def list_themes(
     _: User = Depends(get_current_user),
 ) -> list:
-    return await asyncio.to_thread(load_all_themes)
+    return await load_all_themes()
 
 
 @router.post("/themes", status_code=201)
@@ -263,7 +258,7 @@ async def create_theme(
 ) -> dict:
     if not _THEME_ID_RE.match(body.id):
         raise HTTPException(status_code=422, detail="Theme ID must match [a-z0-9_-]{1,64}")
-    existing = {t["id"] for t in await asyncio.to_thread(load_all_themes)}
+    existing = {t["id"] for t in await load_all_themes()}
     if body.id in existing:
         raise HTTPException(status_code=400, detail=f"Theme ID already in use: {body.id!r}")
     light = body.light.model_dump()
@@ -273,7 +268,7 @@ async def create_theme(
         if errors:
             raise HTTPException(status_code=422, detail=f"{mode}: {'; '.join(errors)}")
     theme = {"id": body.id, "label": body.label, "builtin": False, "light": light, "dark": dark}
-    await asyncio.to_thread(save_theme, theme)
+    await save_theme(theme)
     return theme
 
 
@@ -283,11 +278,9 @@ async def update_theme(
     body: ThemeUpdate,
     _: User = Depends(get_current_admin),
 ) -> dict:
-    from app.core.app_config import _THEMES_DIR
-    path = _THEMES_DIR / f"{theme_id}.json"
-    if not path.exists():
+    theme = await load_theme_by_id(theme_id)
+    if theme is None:
         raise HTTPException(status_code=404, detail="Theme not found")
-    theme = json.loads(path.read_text())
     if theme.get("builtin"):
         raise HTTPException(status_code=400, detail="Cannot edit a built-in theme")
     if body.label is not None:
@@ -304,7 +297,7 @@ async def update_theme(
         if errors:
             raise HTTPException(status_code=422, detail=f"dark: {'; '.join(errors)}")
         theme["dark"] = dark
-    await asyncio.to_thread(save_theme, theme)
+    await save_theme(theme)
     return theme
 
 
@@ -314,7 +307,7 @@ async def remove_theme(
     _: User = Depends(get_current_admin),
 ) -> None:
     try:
-        await asyncio.to_thread(delete_theme, theme_id)
+        await delete_theme(theme_id)
     except FileNotFoundError:
         raise HTTPException(status_code=404, detail="Theme not found")
     except ValueError as exc:
diff --git a/docker-compose.yml b/docker-compose.yml
index 2ec7324..dec204b 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -54,8 +54,6 @@ services:
       DOC_SERVICE_URL: http://doc-service:8001
       AI_SERVICE_URL: http://ai-service:8010
       STORAGE_SERVICE_URL: http://storage-service:8020
-    volumes:
-      - app_config:/config
     depends_on:
       db:
         condition: service_healthy
@@ -73,9 +71,10 @@ services:
     user: "1001:1001"
     restart: unless-stopped
     environment:
-      CONFIG_PATH: /config/ai_service_config.json
-    volumes:
-      - app_config:/config
+      STORAGE_SERVICE_URL: http://storage-service:8020
+    depends_on:
+      storage-service:
+        condition: service_healthy
     networks:
       - backend-net
 
@@ -89,14 +88,10 @@ services:
     restart: unless-stopped
     environment:
       DATABASE_URL: postgresql+asyncpg://${POSTGRES_USER:-postgres}:${POSTGRES_PASSWORD:-password}@db:5432/${POSTGRES_DB:-destroying_sap}
-      DATA_DIR: /data/documents
-      CONFIG_PATH: /config/doc_service_config.json
       AI_SERVICE_URL: http://ai-service:8010
       STORAGE_SERVICE_URL: http://storage-service:8020
     volumes:
-      - doc_data:/data/documents
       - watch_data:/data/watch
-      - app_config:/config
     depends_on:
       db:
         condition: service_healthy
@@ -125,10 +120,8 @@ services:
 
 volumes:
   postgres_data:
-  storage_data:  # All file/blob storage — managed by storage-service
-  doc_data:      # PDF files persisted across restarts (to be removed after Phase 2 migration)
+  storage_data:  # All file/blob storage — managed by storage-service (documents + config)
   watch_data:    # Watch directory — bind-mount your NAS/Nextcloud here via docker-compose.override.yml
-  app_config:    # Per-service runtime config JSON files (to be removed after Phase 3 migration)
 
 networks:
   # backend-net: db ↔ backend ↔ doc-service. No host ports bound.
diff --git a/features/ai-service/app/core/config.py b/features/ai-service/app/core/config.py
index bbeb4d0..7f1f52a 100644
--- a/features/ai-service/app/core/config.py
+++ b/features/ai-service/app/core/config.py
@@ -3,7 +3,7 @@ from pydantic_settings import BaseSettings
 
 class Settings(BaseSettings):
     PROJECT_NAME: str = "ai-service"
-    CONFIG_PATH: str = "/config/ai_service_config.json"
+    STORAGE_SERVICE_URL: str = "http://storage-service:8020"
 
     model_config = {"env_file": ".env", "extra": "ignore"}
 
diff --git a/features/ai-service/app/services/config_reader.py b/features/ai-service/app/services/config_reader.py
index 4caad3a..c5bed16 100644
--- a/features/ai-service/app/services/config_reader.py
+++ b/features/ai-service/app/services/config_reader.py
@@ -1,5 +1,5 @@
 """
-Reads ai_service_config.json from the shared config volume.
+Reads ai_service_config.json from the storage-service config bucket.
 30-second TTL cache + env var overrides (dev credentials stay out of git).
 
 Env var overrides (all optional):
@@ -8,15 +8,17 @@ Env var overrides (all optional):
   OLLAMA_BASE_URL, OLLAMA_MODEL, OLLAMA_API_KEY
   ANTHROPIC_API_KEY, ANTHROPIC_MODEL
 """
-import asyncio
 import json
 import os
 import time
 from copy import deepcopy
-from pathlib import Path
+
+import httpx
 
 from app.core.config import settings
 
+_CONFIG_KEY = "ai_service_config.json"
+
 _DEFAULT_CONFIG: dict = {
     "provider": "lmstudio",
     "timeout_seconds": 60,
@@ -31,12 +33,18 @@ _cache_at: float = 0.0
 _CACHE_TTL = 30.0
 
 
-def _read_config_sync() -> dict:
-    path = Path(settings.CONFIG_PATH)
-    if not path.exists():
-        return _apply_env_overrides(deepcopy(_DEFAULT_CONFIG))
-    with open(path) as f:
-        return _apply_env_overrides(json.load(f))
+def _storage_url() -> str:
+    return f"{settings.STORAGE_SERVICE_URL}/objects/config/{_CONFIG_KEY}"
+
+
+async def _fetch_config() -> dict:
+    """Fetch config from storage-service. Returns defaults if not found."""
+    async with httpx.AsyncClient(timeout=10.0) as client:
+        resp = await client.get(_storage_url())
+        if resp.status_code == 404:
+            return deepcopy(_DEFAULT_CONFIG)
+        resp.raise_for_status()
+        return resp.json()
 
 
 def _apply_env_overrides(config: dict) -> dict:
@@ -75,7 +83,8 @@ async def load_ai_config() -> dict:
     now = time.monotonic()
     if _cache is not None and (now - _cache_at) < _CACHE_TTL:
         return _cache
-    data = await asyncio.to_thread(_read_config_sync)
+    raw = await _fetch_config()
+    data = _apply_env_overrides(raw)
     _cache = data
     _cache_at = now
     return data
diff --git a/features/doc-service/app/services/config_reader.py b/features/doc-service/app/services/config_reader.py
index a3db812..da2dd3d 100644
--- a/features/doc-service/app/services/config_reader.py
+++ b/features/doc-service/app/services/config_reader.py
@@ -1,19 +1,20 @@
 """
-Reads doc_service_config.json from the shared config volume.
+Reads doc_service_config.json from the storage-service config bucket.
 30-second TTL cache + env var overrides.
 
 Env var overrides (all optional):
   DOC_MAX_PDF_MB   — max upload size in megabytes (e.g. "50")
 """
-import asyncio
-import json
 import os
 import time
 from copy import deepcopy
-from pathlib import Path
+
+import httpx
 
 from app.core.config import settings
 
+_CONFIG_KEY = "doc_service_config.json"
+
 _DEFAULT_STORAGE_CONFIG: dict = {
     "watch_enabled": False,
     "watch_path": "/data/watch",
@@ -63,33 +64,30 @@ _cache_at: float = 0.0
 _CACHE_TTL = 30.0
 
 
-def _read_config_sync() -> dict:
-    path = Path(settings.CONFIG_PATH)
-    if not path.exists():
-        base = deepcopy(_DEFAULT_CONFIG)
-    else:
-        with open(path) as f:
-            base = json.load(f)
-    return _apply_env_overrides(base)
+def _storage_url() -> str:
+    return f"{settings.STORAGE_SERVICE_URL}/objects/config/{_CONFIG_KEY}"
 
 
-def _read_config_sync_raw() -> dict:
-    """Read without env overrides — used when we need to write back to disk."""
-    path = Path(settings.CONFIG_PATH)
-    if not path.exists():
-        return deepcopy(_DEFAULT_CONFIG)
-    with open(path) as f:
-        return json.load(f)
+async def _fetch_config() -> dict:
+    """Fetch config from storage-service. Returns defaults if not found."""
+    async with httpx.AsyncClient(timeout=10.0) as client:
+        resp = await client.get(_storage_url())
+        if resp.status_code == 404:
+            return deepcopy(_DEFAULT_CONFIG)
+        resp.raise_for_status()
+        return resp.json()
 
 
-def _write_config_sync(config: dict) -> None:
-    """Atomically write config JSON to disk."""
-    path = Path(settings.CONFIG_PATH)
-    tmp = path.with_suffix(".tmp")
-    tmp.parent.mkdir(parents=True, exist_ok=True)
-    with open(tmp, "w") as f:
-        json.dump(config, f, indent=2)
-    os.replace(tmp, path)
+async def _write_config(data: dict) -> None:
+    import json
+    payload = json.dumps(data, indent=2).encode()
+    async with httpx.AsyncClient(timeout=10.0) as client:
+        resp = await client.put(
+            _storage_url(),
+            content=payload,
+            headers={"Content-Type": "application/octet-stream"},
+        )
+        resp.raise_for_status()
 
 
 def _apply_env_overrides(config: dict) -> dict:
@@ -108,7 +106,8 @@ async def load_doc_config() -> dict:
     now = time.monotonic()
     if _cache is not None and (now - _cache_at) < _CACHE_TTL:
         return _cache
-    data = await asyncio.to_thread(_read_config_sync)
+    raw = await _fetch_config()
+    data = _apply_env_overrides(raw)
     _cache = data
     _cache_at = now
     return data
@@ -123,11 +122,10 @@ async def get_storage_config() -> dict:
 
 
 async def save_storage_config(data: dict) -> None:
-    """Merge data into the storage config block and persist to disk."""
+    """Merge data into the storage config block and persist to storage-service."""
     global _cache, _cache_at
-    raw = await asyncio.to_thread(_read_config_sync_raw)
+    raw = await _fetch_config()
     raw.setdefault("storage", {}).update(data)
-    await asyncio.to_thread(_write_config_sync, raw)
-    # Invalidate cache so next read picks up the new values
+    await _write_config(raw)
     _cache = None
     _cache_at = 0.0