diff --git a/backend/app/api/settings.py b/backend/app/api/settings.py
index 566fae74..d910029d 100644
--- a/backend/app/api/settings.py
+++ b/backend/app/api/settings.py
@@ -10,18 +10,21 @@ from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.api import health
+from app.api.coded import CodedHTTPException
 from app.core.errors import explain, not_configured, raw
 from app.core.config import settings as app_settings
 from app.core.crypto import encrypt, mask
 from app.db.base import get_session
 from app.db.models import Provider, Setting
 from app.engine.judge import JUDGE_DEFAULTS, MAX_TOKENS as JUDGE_MAX_TOKENS
-from app.engine.judge import SETTING_GROUP as JUDGE_GROUP, SPEND_KEY as JUDGE_SPEND
+from app.engine.judge import SETTING_GROUP as JUDGE_GROUP, SETTING_LABEL as JUDGE_LABEL, SPEND_KEY as JUDGE_SPEND
 from app.engine.judge import daily_spend, judge_model_spec, judge_settings
 from app.engine.judge import sanitize_settings as judge_values, settings_problem as judge_problem
 from app.engine.spend import SPEND_KEY as VERIFY_SPEND, daily_spend as verify_daily_spend
 from app.providers import catalog
-from app.providers.factory import ModelSpec, ProviderNotConfigured, _resolve_key, build_chat_model
+from app.providers.factory import (
+    ModelSpec, ProviderNotConfigured, _resolve_key, build_chat_model, list_providers as all_providers, named_provider,
+)
 
 router = APIRouter(prefix="/api", tags=["settings"])
 
@@ -719,6 +722,49 @@ class SettingsIn(BaseModel):
     values: dict[str, Any]
 
 
+#: 点名的模型接入不存在或已停用时 PUT /api/settings 回 422 的机读码，field 是出错的那一项（verify.provider……）
+PROVIDER_INVALID = "settings_provider_invalid"
+
+
+def _provider_fields() -> dict[tuple[str, str], tuple[str, str]]:
+    """设置里点名模型接入的项：(组, 键) → (设置页上的叫法, 留空时用什么)。门控、裁判、核查的叫法和设置页一致；助手的
+    模型由助手面板单独设定（PUT /api/copilot/model），这里只防经设置接口写进去的那一份。"""
+    from app.api.copilot import COPILOT_SETTING_KEY   # 在这里导入：copilot 模块很大，设置模块被引擎各处导入
+
+    return {
+        ("run", "tool_gate_provider"): ("门控模型 · 接入", "留空表示使用默认接入的默认模型"),
+        (JUDGE_GROUP, "provider"): (JUDGE_LABEL["provider"], "留空表示不指定"),
+        (VERIFY_GROUP, "provider"): (VERIFY_SETTING_LABEL["provider"], "留空表示沿用证据裁判模型"),
+        (COPILOT_SETTING_KEY, "provider"): ("助手模型 · 接入", "留空表示不指定"),
+    }
+
+
+async def _provider_problem(session: AsyncSession, values: dict[str, Any]) -> tuple[str, str] | None:
+    """这次写进来的设置里点名的模型接入有没有问题：(字段, 说明)，没问题返回 None。说明和运行时报的原因、提示同一句
+    （factory.named_provider）。
+
+    以前点名的接入不存在时运行悄悄换成演示模型，名字写错一个字就由演示模型写报告、做核查，现在运行时照实报错；保存时
+    先拦一道。留空照旧表示沿用上一级。只查这次改了的：存着的值没改（写好之后接入才被删、停用）不挡这次保存别的项——
+    设置页标着「不存在」，运行时照实报错，同设置页「只校验改过的」的做法。名字不是字符串这类格式问题由各组自己的
+    检查先报。"""
+    providers = None
+    for (group, key), (label, blank) in _provider_fields().items():
+        sent = values.get(group)
+        if not isinstance(sent, dict) or (name := _model_text(sent.get(key))) is None:
+            continue
+        row = await session.get(Setting, group)
+        saved = row.value if row is not None and isinstance(row.value, dict) else {}
+        if _model_text(saved.get(key)) == name:
+            continue
+        if providers is None:
+            providers = await all_providers(session)
+        try:
+            named_provider(providers, name)
+        except ProviderNotConfigured as e:
+            return f"{group}.{key}", f"「{label}」填写的{e.reason}。{e.hint}；{blank}"
+    return None
+
+
 @router.put("/settings")
 async def put_settings(
     payload: SettingsIn, session: AsyncSession = Depends(get_session)
@@ -735,6 +781,8 @@ async def put_settings(
             raise HTTPException(422, problem)
         # 存规范化之后的：末尾带 / 的地址拼链接会多出一个斜杠
         payload.values[NOTIFY_GROUP] = notify_values(payload.values[NOTIFY_GROUP])
+    if found := await _provider_problem(session, payload.values):
+        raise CodedHTTPException(422, found[1], PROVIDER_INVALID, field=found[0])
     for key, value in payload.values.items():
         if key in (TRUST_KEY, "limits", JUDGE_SPEND, VERIFY_SPEND):
             # 信任三档只走 PUT /api/tools/trust：设置页整组回写时带着一份旧的，
diff --git a/backend/app/api/workflows.py b/backend/app/api/workflows.py
index e24a6be8..5bec963f 100644
--- a/backend/app/api/workflows.py
+++ b/backend/app/api/workflows.py
@@ -21,6 +21,8 @@ router = APIRouter(prefix="/api/workflows", tags=["workflows"])
 _GONE = "工作流不存在，可能已被删除"
 _LEVELS = ("published", "governed")
 _BAD_LEVEL = "发布级别只能是「已发布」或「受管」"
+#: 自动修复之后剩下的只有点名接入的问题、人又要交给助手时的说明
+PROVIDER_LEFT = "剩下的问题是节点指定的模型接入不存在或已停用，助手无法代为处理：请在「设置 → 模型接入」中核对，或在节点中换一个接入"
 
 
 class WorkflowIn(BaseModel):
@@ -335,6 +337,7 @@ async def publish_workflow(
 
     checkers = await _sql_checkers(session, spec)
     issues = [i.model_dump() for i in publish_issues(spec, level=payload.level, checkers=checkers)]
+    issues += await _provider_issues(session, spec, level="error")
     if any(i["level"] == "error" for i in issues):
         return {"ok": False, "level": payload.level, "version": version, "issues": issues}
 
@@ -421,6 +424,22 @@ async def _sql_checkers(session: AsyncSession, spec: GraphSpec) -> dict[str, Any
     return await load_checkers_by_name(session, graph_sources(spec.nodes))
 
 
+async def _provider_issues(session: AsyncSession, spec: GraphSpec, *, level: str) -> list[dict[str, Any]]:
+    """节点点名的模型接入不存在或已停用（engine/provider_refs.py）：画布校验给 warning，发布、发布前检查、自动修复的
+    复核给 error、挡住发布。要读接入表，和 _sql_checkers 一样由接口这一层查，门禁本身不查库。没有对应的修复。"""
+    from app.engine.provider_refs import load_issues
+
+    return [i.model_dump() for i in await load_issues(session, spec, level=level)]
+
+
+def _with_provider_issues(out: dict[str, Any], issues: list[dict[str, Any]], key: str) -> dict[str, Any]:
+    """发布前检查（issues）、自动修复（remaining）的结果补上点名接入的问题：都是 error，有就不能发布。"""
+    if issues:
+        out[key] = [*out[key], *issues]
+        out["ok"] = False
+    return out
+
+
 def _unreadable(level: str, e: Exception) -> dict[str, Any]:
     return {"level": level, "ok": False, "fixes": [], "issues": [
         {"level": "error", "node_id": None, "edge_id": None, "field": None, "code": None, "fix": None,
@@ -443,8 +462,8 @@ async def publish_check(
     except Exception as e:  # noqa: BLE001
         return _unreadable(payload.level, e)
     versions, cards = await _gate_context(session, spec)
-    return check(spec, level=payload.level, versions=versions, cards=cards,
-                 checkers=await _sql_checkers(session, spec))
+    out = check(spec, level=payload.level, versions=versions, cards=cards, checkers=await _sql_checkers(session, spec))
+    return _with_provider_issues(out, await _provider_issues(session, spec, level="error"), "issues")
 
 
 @router.post("/{workflow_id}/autofix")
@@ -475,9 +494,11 @@ async def autofix(
     # 人在选项里选了「交给 Copilot」（handoff），和点「交给 Copilot」是一回事
     if payload.assist or out["handoff"]:
         if out["ok"]:
-            out["assist"] = {"ok": True, "summary": "修复后已没有阻止发布的错误，未再交给助手",
+            # 剩下的只有点名接入的问题时不这么说：助手改不了接入表，也不知道该换成哪个接入
+            lost = await _provider_issues(session, GraphSpec.model_validate(out["graph"]), level="error")
+            out["assist"] = {"ok": not lost, "summary": PROVIDER_LEFT if lost else "修复后已没有阻止发布的错误，未再交给助手",
                              "questions": []}
-            return out
+            return _with_provider_issues(out, lost, "remaining")
         from app.api.copilot import assist_publish_fix
 
         helped = await assist_publish_fix(session, out["graph"], level=payload.level,
@@ -493,7 +514,8 @@ async def autofix(
             out.update(graph=fixed, remaining=after["remaining"], fixes=after["fixes"], ok=after["ok"])
         elif helped["reason"]:
             out["rejected"].append({"fix_id": "assist", "reason": helped["reason"]})
-    return out
+    return _with_provider_issues(out, await _provider_issues(session, GraphSpec.model_validate(out["graph"]),
+                                                             level="error"), "remaining")
 
 
 class ValidateIn(BaseModel):
@@ -501,14 +523,17 @@ class ValidateIn(BaseModel):
 
 
 @router.post("/validate")
-async def validate(payload: ValidateIn) -> dict[str, Any]:
-    """画布上的实时校验。前端每次改动都会调它来标红。"""
+async def validate(payload: ValidateIn, session: AsyncSession = Depends(get_session)) -> dict[str, Any]:
+    """画布上的实时校验。前端每次改动都会调它来标红。
+
+    点名的模型接入不存在或已停用只给警告：探索运行仍可发起，执行到那个节点时照实报错；发布时才挡住。"""
     try:
         spec = GraphSpec.model_validate(payload.graph)
     except Exception as e:  # noqa: BLE001
         return {"ok": False, "issues": [{"level": "error", "message": f"无法解析工作流结构：{graph_error(e)}"}]}
-    result = validate_graph(spec)
-    return result.model_dump()
+    result = validate_graph(spec).model_dump()
+    result["issues"] += await _provider_issues(session, spec, level="warning")
+    return result
 
 
 @router.post("/variables")
diff --git a/backend/app/engine/provider_refs.py b/backend/app/engine/provider_refs.py
new file mode 100644
index 00000000..5968c6c1
--- /dev/null
+++ b/backend/app/engine/provider_refs.py
@@ -0,0 +1,113 @@
+"""工作流里点名的模型接入：不存在或已停用的，画布校验、发布前检查、发布时照实提出来。
+
+运行时点名的接入不存在或已停用直接报错（providers/factory.named_provider），以前是悄悄换成演示模型。这类问题发布前
+就该看得到：画布校验给警告（探索运行仍可发起，执行到那里报错），发布、发布前检查、自动修复的复核给错误、挡住
+发布——正式运行到那里一定失败，或者少一块核查。
+
+查的是执行时真会去取模型的那几处，取法和执行器一致：
+- 模型调用、Agent、报告撰写、多 Agent 协作的接入；条件分支只在「让模型分类」时、结构校验只在「让模型修复」时、
+  知识检索只在「让模型重排」时才取模型。这几类节点没写自己的接入时取全图默认（NodeContext.cfg）；
+- 多 Agent 协作各成员的接入；报告撰写交给模型裁判结论句时，「结论句裁判」里的接入；
+- 双盲复算、反方审稿的接入（核查模型）：只读节点自己的配置，不取全图默认；
+- 全图默认的接入：有节点会取到它时才查。
+
+接入表要读库，门禁本身不查库（governance.lint_for_publish），所以由接口这一层读出接入表交给 issues()，同数据目录
+SQL 检查器的做法。设置里点名接入的几项由 api/settings.py 在保存时查。
+"""
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Any, Callable
+
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.engine.labels import field_label, type_label
+from app.engine.schema import CLAIMS_JUDGE, GraphNode, GraphSpec, NodeType, ValidationIssue
+from app.providers.factory import ProviderNotConfigured, list_providers, named_provider
+
+
+def _cfg(spec: GraphSpec, node: GraphNode, key: str, default: Any = None) -> Any:
+    """和 NodeContext.cfg 同一个规则：节点上没写（None、空串）就取全图默认。"""
+    value = node.config.get(key)
+    return spec.defaults.get(key, default) if value in (None, "") else value
+
+
+#: 按 NodeContext.cfg 取接入的节点 → 执行时真会去取模型的条件（None 是总会取）
+_TAKES_MODEL: dict[NodeType, Callable[[GraphSpec, GraphNode], bool] | None] = {
+    NodeType.LLM: None,
+    NodeType.AGENT: None,
+    NodeType.REPORT: None,
+    NodeType.SUPERVISOR: None,
+    NodeType.BRANCH: lambda spec, node: _cfg(spec, node, "mode", "expression") == "llm",
+    NodeType.VALIDATE: lambda spec, node: bool(_cfg(spec, node, "repair_with_llm", True)),
+    NodeType.RETRIEVE: lambda spec, node: _cfg(spec, node, "rerank", "off") == "model",
+}
+#: 核查节点：接入只读节点自己的配置（verify_model_spec），图级默认的接入是写作模型的
+_VERIFY = {NodeType.DUAL_CHECK: "的盲算模型", NodeType.CHALLENGE: "的反方模型"}
+
+
+def _name(value: Any) -> str | None:
+    return value.strip() or None if isinstance(value, str) else None
+
+
+@dataclass(frozen=True)
+class ProviderRef:
+    """图里点名接入的一处：落在哪个节点（全图默认为 None）、哪个字段，点的名字，句子里怎么称呼这一处。"""
+
+    node_id: str | None
+    field: str
+    name: str
+    who: str
+
+
+def provider_refs(spec: GraphSpec) -> list[ProviderRef]:
+    """图里执行时会用到的接入点名，按画布上节点的顺序，全图默认排最后。"""
+    out: list[ProviderRef] = []
+    falls_back = False
+    for node in spec.nodes:
+        cfg = node.config
+        who = f"「{node.title}」（{type_label(node.type)}）"
+        if node.type in _VERIFY:
+            if name := _name(cfg.get("provider")):
+                out.append(ProviderRef(node.id, "provider", name, who + _VERIFY[node.type]))
+            continue
+        if node.type not in _TAKES_MODEL:
+            continue
+        cond = _TAKES_MODEL[node.type]
+        if cond is None or cond(spec, node):
+            if name := _name(cfg.get("provider")):
+                out.append(ProviderRef(node.id, "provider", name, who))
+            else:
+                falls_back = True
+        if node.type == NodeType.SUPERVISOR and isinstance(cfg.get("agents"), list):
+            for i, member in enumerate(cfg["agents"]):
+                if isinstance(member, dict) and (name := _name(member.get("provider"))):
+                    label = _name(member.get("name")) or f"第 {i + 1} 位"
+                    out.append(ProviderRef(node.id, f"agents[{i}].provider", name, f"{who}的成员「{label}」"))
+        if node.type == NodeType.REPORT and _cfg(spec, node, "claims", "off") == CLAIMS_JUDGE \
+                and isinstance(cfg.get("judge"), dict) and (name := _name(cfg["judge"].get("provider"))):
+            out.append(ProviderRef(node.id, "judge.provider", name, f"{who}的{field_label('judge')}"))
+    if falls_back and (name := _name(spec.defaults.get("provider"))):
+        out.append(ProviderRef(None, "defaults.provider", name, field_label("defaults")))
+    return out
+
+
+def issues(refs: list[ProviderRef], providers: list[Any], *, level: str) -> list[ValidationIssue]:
+    """点名的接入不存在或已停用的每一处一条问题。providers 是接入表（factory.list_providers），level 由调用方定：
+    画布校验 warning，发布一类 error。说法取自 named_provider，和运行时报的原因、提示同一句。"""
+    out: list[ValidationIssue] = []
+    for ref in refs:
+        try:
+            named_provider(providers, ref.name)
+        except ProviderNotConfigured as e:
+            out.append(ValidationIssue(level=level, node_id=ref.node_id, field=ref.field,  # type: ignore[arg-type]
+                                       code=f"provider.{e.code}", message=f"{ref.who}指定的{e.reason}。{e.hint}"))
+    return out
+
+
+async def load_issues(session: AsyncSession, spec: GraphSpec, *, level: str) -> list[ValidationIssue]:
+    """读接入表、查一遍。图里没点名任何接入时不读库。"""
+    refs = provider_refs(spec)
+    if not refs:
+        return []
+    return issues(refs, await list_providers(session), level=level)
diff --git a/backend/tests/test_provider_ref_checks.py b/backend/tests/test_provider_ref_checks.py
new file mode 100644
index 00000000..68158f17
--- /dev/null
+++ b/backend/tests/test_provider_ref_checks.py
@@ -0,0 +1,281 @@
+"""保存设置、校验画布、发布时就查出点名了不存在或已停用的模型接入（运行时它们会照实报错，见 test_provider_ref_runtime）。
+
+- PUT /api/settings：引用接入的几项（核查模型、证据裁判、门控模型、助手）写了不存在或已停用的接入 → 422，带 field、
+  code 和设置页上的叫法；一组出错整次不落库。留空照旧表示沿用上一级；存着的值没改（写好之后接入才被删、停用）不挡
+  这次保存别的项——设置页标着「不存在」，运行时照实报错；
+- 画布校验：节点点名的接入不存在或已停用给警告，说清哪个节点、哪个接入；发布前检查、发布、自动修复的复核给错误，
+  挡住发布。只查执行时真会去取模型的那几处（分支「让模型分类」、校验「让模型修复」、检索「让模型重排」时才算）。
+
+接入名、节点名都是虚构的。
+"""
+from __future__ import annotations
+
+import uuid
+
+import pytest
+from httpx import ASGITransport, AsyncClient
+from sqlalchemy import delete
+
+from app.db.base import SessionLocal
+from app.db.models import Provider, Setting, Workflow, WorkflowVersion
+from app.main import app
+
+LIVE, OFF, GONE = "核对用接入", "核对用停用接入", "核对用接人"
+SETTING_KEYS = ["verify", "judge", "copilot", "run"]
+
+
+async def _clean() -> None:
+    async with SessionLocal() as session:
+        await session.execute(delete(Setting).where(Setting.key.in_(SETTING_KEYS)))
+        await session.execute(delete(Provider).where(Provider.name.in_([LIVE, OFF])))
+        await session.commit()
+
+
+@pytest.fixture(autouse=True)
+async def providers():
+    """一个启用、一个停用的接入（都是演示类，不联网）；用完删掉，免得改变同一进程里别的测试「没点名」时的回退。"""
+    await _clean()
+    async with SessionLocal() as session:
+        live = Provider(name=LIVE, kind="mock", models=[{"id": "核对模型"}], default_model="核对模型", enabled=True,
+                        extra={})
+        off = Provider(name=OFF, kind="mock", models=[{"id": "核对停用模型"}], default_model="核对停用模型",
+                       enabled=False, extra={})
+        session.add_all([live, off])
+        await session.commit()
+        ids = {LIVE: live.id, OFF: off.id}
+    yield ids
+    await _clean()
+
+
+@pytest.fixture
+async def client():
+    async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as c:
+        yield c
+
+
+async def stored(key: str):
+    async with SessionLocal() as session:
+        row = await session.get(Setting, key)
+        return row.value if row else None
+
+
+# --------------------------------------------------------------------------
+# 保存设置
+# --------------------------------------------------------------------------
+
+#: (组, 键, 设置页上的叫法)
+FIELDS = [
+    ("verify", "provider", "核查模型 · 接入"),
+    ("judge", "provider", "裁判模型 · 接入"),
+    ("run", "tool_gate_provider", "门控模型 · 接入"),
+    ("copilot", "provider", "助手模型 · 接入"),
+]
+
+
+@pytest.mark.parametrize("group,key,label", FIELDS)
+async def test_saving_a_provider_that_does_not_exist_is_refused_with_the_field(client, group, key, label):
+    r = await client.put("/api/settings", json={"values": {group: {key: GONE}}})
+    assert r.status_code == 422, r.text
+    body = r.json()
+    assert body["code"] == "settings_provider_invalid" and body["field"] == f"{group}.{key}"
+    assert body["detail"].startswith(f"「{label}」填写的模型接入「{GONE}」不存在。"), body["detail"]
+    assert "请在「设置 → 模型接入」中核对名称，或换一个接入" in body["detail"] and "留空表示" in body["detail"]
+    assert await stored(group) is None
+
+
+@pytest.mark.parametrize("group,key,label", FIELDS)
+async def test_saving_a_disabled_provider_is_refused_too(client, group, key, label):
+    r = await client.put("/api/settings", json={"values": {group: {key: OFF}}})
+    assert r.status_code == 422, r.text
+    body = r.json()
+    assert body["field"] == f"{group}.{key}"
+    assert body["detail"].startswith(f"「{label}」填写的模型接入「{OFF}」已停用。"), body["detail"]
+    assert "请在「设置 → 模型接入」中启用它，或换一个接入" in body["detail"]
+    assert await stored(group) is None
+
+
+async def test_one_bad_group_keeps_the_whole_request_out_of_the_database(client):
+    r = await client.put("/api/settings", json={"values": {
+        "run": {"default_memory_scope": "门店", "tool_gate_provider": LIVE},
+        "judge": {"provider": LIVE, "model": None},
+        "verify": {"provider": GONE},
+    }})
+    assert r.status_code == 422 and r.json()["field"] == "verify.provider"
+    assert await stored("run") is None and await stored("judge") is None and await stored("verify") is None
+
+
+async def test_blank_means_inherit_and_an_enabled_provider_is_taken_by_name_or_id(client, providers):
+    r = await client.put("/api/settings", json={"values": {
+        "verify": {"provider": None, "model": "核对模型"},
+        "judge": {"provider": "  "},
+        "run": {"tool_gate_provider": ""},
+    }})
+    assert r.status_code == 200, r.text
+    r = await client.put("/api/settings", json={"values": {
+        "verify": {"provider": LIVE}, "judge": {"provider": providers[LIVE]},
+        "run": {"tool_gate_provider": LIVE}, "copilot": {"provider": LIVE, "model": ""},
+    }})
+    assert r.status_code == 200, r.text
+    got = r.json()
+    assert got["verify"]["provider"] == LIVE and got["judge"]["provider"] == providers[LIVE]
+    assert got["run"]["tool_gate_provider"] == LIVE
+
+
+async def test_a_stored_provider_removed_later_does_not_block_saving_the_rest_of_its_group(client):
+    """写好之后接入才被删掉：存着的值没改，这次保存别的项照常（运行时照实报错，设置页标着「不存在」）。
+    改成另一个不存在的名字仍然拦下。"""
+    async with SessionLocal() as session:
+        session.add(Setting(key="verify", value={"provider": GONE, "daily_max_usd": 2.0}))
+        await session.commit()
+    r = await client.put("/api/settings", json={"values": {"verify": {"provider": f" {GONE} ", "daily_max_usd": 3}}})
+    assert r.status_code == 200, r.text
+    assert (await stored("verify"))["daily_max_usd"] == 3
+    r = await client.put("/api/settings", json={"values": {"verify": {"provider": "另一个不存在的接入"}}})
+    assert r.status_code == 422 and r.json()["field"] == "verify.provider"
+
+
+async def test_format_problems_are_still_reported_first(client):
+    r = await client.put("/api/settings", json={"values": {"verify": {"provider": 3}}})
+    assert r.status_code == 422
+    assert "需要填写模型接入的名称或模型 ID" in r.json()["detail"]
+
+
+# --------------------------------------------------------------------------
+# 画布校验、发布前检查、发布
+# --------------------------------------------------------------------------
+
+
+def node(nid, ntype, label=None, **config):
+    return {"id": nid, "type": ntype, "position": {"x": 0, "y": 0}, "data": {"label": label or nid, "config": config}}
+
+
+def chain(*nodes, defaults=None):
+    graph = {"nodes": list(nodes), "edges": [{"source": a["id"], "target": b["id"]} for a, b in zip(nodes, nodes[1:])]}
+    if defaults:
+        graph["defaults"] = defaults
+    return graph
+
+
+def writer(ref: str | None, **extra) -> dict:
+    return chain(node("start", "input"),
+                 node("write", "llm", "写周报", **({"provider": ref} if ref else {}), prompt="写周报", **extra),
+                 node("out", "output", fields=[{"name": "周报", "value": "{{ nodes.write.text }}"}]))
+
+
+def provider_issues(result: dict) -> list[dict]:
+    return [i for i in result["issues"] if str(i.get("code") or "").startswith("provider.")]
+
+
+@pytest.mark.parametrize("ref,code,state", [(GONE, "provider.missing", "不存在"), (OFF, "provider.disabled", "已停用")])
+async def test_validation_warns_about_a_node_naming_a_broken_provider(client, ref, code, state):
+    r = await client.post("/api/workflows/validate", json={"graph": writer(ref)})
+    assert r.status_code == 200, r.text
+    [issue] = provider_issues(r.json())
+    assert issue["level"] == "warning" and issue["code"] == code
+    assert (issue["node_id"], issue["field"]) == ("write", "provider")
+    assert issue["message"].startswith(f"「写周报」（模型调用）指定的模型接入「{ref}」{state}。"), issue["message"]
+    assert r.json()["ok"] is True, "只是警告：探索运行仍可发起，执行到那里照实报错"
+
+
+async def test_validation_is_quiet_for_an_enabled_provider_or_none(client, providers):
+    for ref in (LIVE, providers[LIVE], None):
+        r = await client.post("/api/workflows/validate", json={"graph": writer(ref)})
+        assert provider_issues(r.json()) == [], ref
+
+
+async def test_every_place_a_graph_names_a_provider_is_checked(client):
+    graph = chain(
+        node("start", "input"),
+        node("team", "supervisor", "协作", provider=OFF, agents=[{"name": "分析师", "provider": GONE, "system": "分析"},
+                                                                 {"provider": LIVE, "system": "复核"}]),
+        node("write", "report", "写周报", instructions="写周报", claims="judge", judge={"provider": GONE}),
+        node("dual", "dual_check", "复核销售额", provider=GONE),
+        node("chal", "challenge", "审稿", report="write", provider=OFF),
+        node("ask", "llm", "提问", prompt="总结"),        # 没写接入：取全图默认
+        node("out", "output", fields=[{"name": "周报", "value": "{{ nodes.write.text }}"}]),
+        defaults={"provider": GONE},
+    )
+    r = await client.post("/api/workflows/validate", json={"graph": graph})
+    got = {(i["node_id"], i["field"]): i for i in provider_issues(r.json())}
+    assert set(got) == {("team", "provider"), ("team", "agents[0].provider"), ("write", "judge.provider"),
+                        ("dual", "provider"), ("chal", "provider"), (None, "defaults.provider")}
+    assert got[("team", "agents[0].provider")]["message"].startswith(
+        f"「协作」（多 Agent 协作）的成员「分析师」指定的模型接入「{GONE}」不存在")
+    assert got[("write", "judge.provider")]["message"].startswith(
+        f"「写周报」（报告撰写）的结论句裁判指定的模型接入「{GONE}」不存在")
+    assert got[("dual", "provider")]["message"].startswith(f"「复核销售额」（双盲复算）的盲算模型指定的模型接入「{GONE}」")
+    assert got[("chal", "provider")]["message"].startswith(f"「审稿」（反方审稿）的反方模型指定的模型接入「{OFF}」已停用")
+    assert got[(None, "defaults.provider")]["message"].startswith(f"工作流默认设置指定的模型接入「{GONE}」不存在")
+
+
+async def test_only_places_that_actually_call_a_model_are_checked(client):
+    """分支按表达式判断、校验不让模型修复、检索不让模型重排时根本不取模型；报告不交给模型裁判时裁判的接入用不上；
+    每个节点都写了自己的接入时，全图默认的接入没人用。"""
+    graph = chain(
+        node("start", "input"),
+        node("route", "branch", "分流", mode="expression", provider=GONE, cases=[{"key": "a", "condition": "true"}]),
+        node("check", "validate", "校验", repair_with_llm=False, provider=GONE, schema={"type": "object"}),
+        node("look", "retrieve", "检索", rerank="off", provider=GONE),
+        node("write", "report", "写周报", instructions="写周报", provider=LIVE, judge={"provider": GONE}),
+        node("out", "output", fields=[{"name": "周报", "value": "{{ nodes.write.text }}"}]),
+        defaults={"provider": GONE},
+    )
+    r = await client.post("/api/workflows/validate", json={"graph": graph})
+    assert provider_issues(r.json()) == []
+    graph["nodes"][1]["data"]["config"]["mode"] = "llm"
+    graph["nodes"][3]["data"]["config"]["rerank"] = "model"
+    r = await client.post("/api/workflows/validate", json={"graph": graph})
+    assert {i["node_id"] for i in provider_issues(r.json())} == {"route", "look"}
+    # 分类的分支不写自己的接入：取全图默认，默认里的接入这才有人用
+    del graph["nodes"][1]["data"]["config"]["provider"]
+    r = await client.post("/api/workflows/validate", json={"graph": graph})
+    assert {(i["node_id"], i["field"]) for i in provider_issues(r.json())} == {("look", "provider"),
+                                                                              (None, "defaults.provider")}
+
+
+async def _workflow(graph: dict) -> str:
+    async with SessionLocal() as session:
+        wf = Workflow(name=f"门店周报-{uuid.uuid4().hex[:6]}", graph=graph, version=1)
+        session.add(wf)
+        await session.flush()
+        session.add(WorkflowVersion(workflow_id=wf.id, version=1, graph=graph))
+        await session.commit()
+        return wf.id
+
+
+@pytest.mark.parametrize("level", ["published", "governed"])
+async def test_publish_check_and_publish_stop_at_a_broken_provider(client, level):
+    wf = await _workflow(writer(GONE))
+    r = await client.post(f"/api/workflows/{wf}/publish-check", json={"level": level})
+    assert r.status_code == 200, r.text
+    check = r.json()
+    [issue] = provider_issues(check)
+    assert issue["level"] == "error" and issue["node_id"] == "write" and issue["fix"] is None
+    assert check["ok"] is False
+    r = await client.post(f"/api/workflows/{wf}/publish", json={"level": level})
+    body = r.json()
+    assert body["ok"] is False and [i["code"] for i in provider_issues(body)] == ["provider.missing"]
+    async with SessionLocal() as session:
+        row = await session.get(Workflow, wf)
+        assert row.published_version is None and row.status == "draft"
+
+
+async def test_publish_check_reads_the_unsaved_canvas_and_autofix_keeps_the_problem(client):
+    wf = await _workflow(writer(None))
+    r = await client.post(f"/api/workflows/{wf}/publish-check", json={"level": "published", "graph": writer(OFF)})
+    assert r.json()["ok"] is False and [i["code"] for i in provider_issues(r.json())] == ["provider.disabled"]
+    r = await client.post(f"/api/workflows/{wf}/autofix", json={"level": "published", "graph": writer(OFF)})
+    assert r.status_code == 200, r.text
+    out = r.json()
+    assert out["ok"] is False
+    assert [(i["code"], i["level"]) for i in provider_issues({"issues": out["remaining"]})] == [
+        ("provider.disabled", "error")]
+    # 换成启用的接入：不再拦
+    r = await client.post(f"/api/workflows/{wf}/publish-check", json={"level": "published", "graph": writer(LIVE)})
+    assert provider_issues(r.json()) == [] and r.json()["ok"] is True
+
+
+async def test_publishing_a_clean_graph_is_unaffected(client):
+    wf = await _workflow(writer(LIVE))
+    r = await client.post(f"/api/workflows/{wf}/publish", json={"level": "published"})
+    assert r.json()["ok"] is True, r.text
diff --git a/backend/tests/test_verify_settings.py b/backend/tests/test_verify_settings.py
index b94fd3fb..e6a2c313 100644
--- a/backend/tests/test_verify_settings.py
+++ b/backend/tests/test_verify_settings.py
@@ -21,7 +21,7 @@ from app.api.settings import (
     verify_settings,
 )
 from app.db.base import SessionLocal
-from app.db.models import Setting
+from app.db.models import Provider, Setting
 from app.engine import spend
 from app.engine.judge import JUDGE_DEFAULTS, MAX_TOKENS
 from app.main import app
@@ -64,7 +64,20 @@ async def test_settings_expose_the_verify_group_with_defaults():
     assert spend.SPEND_KEY not in got
 
 
-async def test_a_full_group_round_trips_and_null_stays_unlimited():
+@pytest.fixture
+async def house():
+    """设置里点名的接入要真的存在、启用着（保存时会查）：建一个演示类的，用完删掉。"""
+    async with SessionLocal() as session:
+        session.add(Provider(name="house", kind="mock", models=[{"id": "verify-model"}], default_model="verify-model",
+                             enabled=True, extra={}))
+        await session.commit()
+    yield "house"
+    async with SessionLocal() as session:
+        await session.execute(delete(Provider).where(Provider.name == "house"))
+        await session.commit()
+
+
+async def test_a_full_group_round_trips_and_null_stays_unlimited(house):
     value = {
         "provider": "house", "model": "verify-model",
         "dual_check": {"enabled": False, "tolerance": 0, "max_queries": None, "timeout_s": None},