diff --git a/src/langbot/pkg/api/http/service/mcp.py b/src/langbot/pkg/api/http/service/mcp.py
index e0c64b9f6..9db699c20 100644
--- a/src/langbot/pkg/api/http/service/mcp.py
+++ b/src/langbot/pkg/api/http/service/mcp.py
@@ -141,15 +141,25 @@ class MCPService:
runtime_mcp_session: RuntimeMCPSession | None = None
+ ctx = taskmgr.TaskContext.new()
+
if server_name != '_':
runtime_mcp_session = self.ap.tool_mgr.mcp_tool_loader.get_session(server_name)
if runtime_mcp_session is None:
raise ValueError(f'Server not found: {server_name}')
- if runtime_mcp_session.status == MCPSessionStatus.ERROR:
- coroutine = runtime_mcp_session.start()
- else:
- coroutine = runtime_mcp_session.refresh()
+ persisted_session = runtime_mcp_session
+
+ async def _refresh_and_report() -> None:
+ if persisted_session.status == MCPSessionStatus.ERROR:
+ await persisted_session.start()
+ else:
+ await persisted_session.refresh()
+ # Surface the discovered tools so the config page can render them
+ # even for an already-hosted server.
+ ctx.metadata['runtime_info'] = persisted_session.get_runtime_info_dict()
+
+ coroutine = _refresh_and_report()
else:
runtime_mcp_session = await self.ap.tool_mgr.mcp_tool_loader.load_mcp_server(server_config=server_data)
@@ -160,6 +170,12 @@ class MCPService:
async def _run_and_cleanup() -> None:
try:
await test_session.start()
+ # Capture the runtime info (status + discovered tools) BEFORE
+ # shutting the transient session down. The create/edit config
+ # page has no persisted server to reload from, so without this
+ # a successful test could only show "no tools found". The
+ # frontend reads ctx.metadata.runtime_info to render the tools.
+ ctx.metadata['runtime_info'] = test_session.get_runtime_info_dict()
finally:
try:
await test_session.shutdown()
@@ -171,7 +187,6 @@ class MCPService:
coroutine = _run_and_cleanup()
- ctx = taskmgr.TaskContext.new()
wrapper = self.ap.task_mgr.create_user_task(
coroutine,
kind='mcp-operation',
diff --git a/src/langbot/pkg/entity/persistence/mcp.py b/src/langbot/pkg/entity/persistence/mcp.py
index 31348fcea..983fdce53 100644
--- a/src/langbot/pkg/entity/persistence/mcp.py
+++ b/src/langbot/pkg/entity/persistence/mcp.py
@@ -9,7 +9,7 @@ class MCPServer(Base):
uuid = sqlalchemy.Column(sqlalchemy.String(255), primary_key=True, unique=True)
name = sqlalchemy.Column(sqlalchemy.String(255), nullable=False)
enable = sqlalchemy.Column(sqlalchemy.Boolean, nullable=False, default=False)
- mode = sqlalchemy.Column(sqlalchemy.String(255), nullable=False) # stdio, sse, http
+ mode = sqlalchemy.Column(sqlalchemy.String(255), nullable=False) # stdio, remote (legacy: sse, http)
extra_args = sqlalchemy.Column(sqlalchemy.JSON, nullable=False, default={})
# Markdown documentation captured from LangBot Space at install time so the
# detail page can show docs even when the server is offline / has no tools.
diff --git a/src/langbot/pkg/persistence/alembic/versions/0006_normalize_mcp_remote_mode.py b/src/langbot/pkg/persistence/alembic/versions/0006_normalize_mcp_remote_mode.py
new file mode 100644
index 000000000..1b5410d95
--- /dev/null
+++ b/src/langbot/pkg/persistence/alembic/versions/0006_normalize_mcp_remote_mode.py
@@ -0,0 +1,51 @@
+"""normalize mcp_servers transport mode to local/remote
+
+The MCP transport selection for servers LangBot connects to was simplified
+from three persisted modes (``stdio`` / ``sse`` / ``http``) down to two:
+``stdio`` (local, Box-sandboxed) and ``remote`` (the runtime auto-detects
+Streamable HTTP vs. legacy SSE from the URL). This migration rewrites any
+existing ``sse`` / ``http`` rows to ``remote`` so the stored value matches the
+new two-option UI. The connection args (url / headers / timeout /
+ssereadtimeout) live in ``extra_args`` and are left untouched — the
+auto-detecting remote transport consumes them regardless.
+
+Revision ID: 0006_normalize_mcp_remote_mode
+Revises: 0005_add_llm_context_length
+Create Date: 2026-06-21
+"""
+
+import sqlalchemy as sa
+from alembic import op
+
+revision = '0006_normalize_mcp_remote_mode'
+down_revision = '0005_add_llm_context_length'
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+ # Idempotent data migration: collapse legacy remote transports into the
+ # unified ``remote`` mode. Guard against the table being absent (truly empty
+ # DB migrated before create_all()).
+ conn = op.get_bind()
+ inspector = sa.inspect(conn)
+ if 'mcp_servers' not in inspector.get_table_names():
+ return
+ conn.execute(
+ sa.text("UPDATE mcp_servers SET mode = 'remote' WHERE mode IN ('sse', 'http')")
+ )
+
+
+def downgrade() -> None:
+ # The legacy distinction between ``sse`` and ``http`` cannot be recovered
+ # from ``remote`` alone (the transport is auto-detected at runtime, not
+ # stored). Map everything that is not ``stdio`` back to ``http`` as a
+ # best-effort reversal — both legacy modes still route correctly in the
+ # backend lifecycle dispatch.
+ conn = op.get_bind()
+ inspector = sa.inspect(conn)
+ if 'mcp_servers' not in inspector.get_table_names():
+ return
+ conn.execute(
+ sa.text("UPDATE mcp_servers SET mode = 'http' WHERE mode = 'remote'")
+ )
diff --git a/src/langbot/pkg/plugin/connector.py b/src/langbot/pkg/plugin/connector.py
index 12413e49d..9cef9cb67 100644
--- a/src/langbot/pkg/plugin/connector.py
+++ b/src/langbot/pkg/plugin/connector.py
@@ -248,6 +248,15 @@ class PluginRuntimeConnector(ManagedRuntimeConnector):
mode = mcp_data.get('mode') or 'stdio'
extra_args = mcp_data.get('extra_args') or {}
+ # The MCP transport selection was simplified to two modes: 'stdio'
+ # (local, Box-sandboxed) and 'remote' (the runtime auto-detects
+ # Streamable HTTP vs. legacy SSE from the URL). Marketplace records may
+ # still carry the older 'http'/'sse' modes — normalize them to 'remote'
+ # so the installed server shows up correctly in the two-option UI. The
+ # connection args (url/headers/timeout/ssereadtimeout) are preserved and
+ # consumed by the auto-detecting remote transport regardless.
+ if mode in ('http', 'sse'):
+ mode = 'remote'
# Marketplace records carry the rendered README markdown; persist it so
# the detail page Docs tab works offline and without a marketplace round-trip.
readme = mcp_data.get('readme') or ''
diff --git a/src/langbot/pkg/provider/tools/loaders/mcp.py b/src/langbot/pkg/provider/tools/loaders/mcp.py
index 8049b185d..8ef7d85e7 100644
--- a/src/langbot/pkg/provider/tools/loaders/mcp.py
+++ b/src/langbot/pkg/provider/tools/loaders/mcp.py
@@ -167,6 +167,38 @@ class RuntimeMCPSession:
await self.session.initialize()
+ async def _init_remote_server(self):
+ """Connect to a remote MCP server, auto-detecting the transport.
+
+ The user only supplies a URL ("remote" mode); they should not have to
+ know whether the server speaks the modern Streamable HTTP transport or
+ the legacy HTTP+SSE transport. Following the MCP backwards-compatibility
+ guidance, we try Streamable HTTP first and fall back to SSE when it
+ fails (e.g. the endpoint returns 4xx to the initialize POST).
+ """
+ try:
+ await self._init_streamable_http_server()
+ return
+ except Exception as e:
+ self.ap.logger.info(
+ f'MCP server {self.server_name}: Streamable HTTP transport failed '
+ f'({self._describe_exception(e)}), falling back to SSE'
+ )
+
+ # The Streamable HTTP attempt may have partially entered the transport /
+ # session into the exit stack before failing. Tear it down and start
+ # from a clean stack before trying SSE so we do not leak connections.
+ try:
+ await self.exit_stack.aclose()
+ except Exception as cleanup_err:
+ self.ap.logger.debug(
+ f'MCP server {self.server_name}: error cleaning up before SSE fallback: {cleanup_err}'
+ )
+ self.exit_stack = AsyncExitStack()
+ self.session = None
+
+ await self._init_sse_server()
+
_MAX_RETRIES = 3
_RETRY_DELAYS = [2, 4, 8]
@@ -175,6 +207,8 @@ class RuntimeMCPSession:
try:
if self.server_config['mode'] == 'stdio':
await self._init_stdio_python_server()
+ elif self.server_config['mode'] == 'remote':
+ await self._init_remote_server()
elif self.server_config['mode'] == 'sse':
await self._init_sse_server()
elif self.server_config['mode'] == 'http':
diff --git a/web/src/app/home/mcp/components/mcp-form/MCPForm.tsx b/web/src/app/home/mcp/components/mcp-form/MCPForm.tsx
index ae5f2ace5..e92d635f8 100644
--- a/web/src/app/home/mcp/components/mcp-form/MCPForm.tsx
+++ b/web/src/app/home/mcp/components/mcp-form/MCPForm.tsx
@@ -47,8 +47,7 @@ import {
MCPTool,
MCPServer,
MCPSessionStatus,
- MCPServerExtraArgsSSE,
- MCPServerExtraArgsHttp,
+ MCPServerExtraArgsRemote,
MCPServerExtraArgsStdio,
} from '@/app/infra/entities/api';
import { CustomApiError } from '@/app/infra/entities/common';
@@ -246,17 +245,18 @@ function ToolsList({ tools, t }: { tools: MCPTool[]; t: TFunction }) {
}
function RuntimePanel({
- isEditMode,
mcpTesting,
runtimeInfo,
t,
}: {
- isEditMode: boolean;
mcpTesting: boolean;
runtimeInfo: MCPServerRuntimeInfo | null;
t: TFunction;
}) {
- if (!isEditMode || !runtimeInfo) {
+ // Show tools whenever we have runtime info — either an edit-mode server or a
+ // create-mode test result captured from the transient session. Only fall back
+ // to the placeholder when there is genuinely nothing to show.
+ if (!runtimeInfo) {
return (
- );
- }
-
- // Stdio MCP refused because Box is disabled / unreachable. The backend
- // marks the phase so we can show a localized, actionable message instead
- // of the raw "box_disabled_in_config" / "box_unavailable" marker.
- if (runtimeInfo.error_phase === 'box_unavailable') {
- const isDisabledByConfig =
- runtimeInfo.error_message === 'box_disabled_in_config';
- return (
-