feat(mcp): support mcp resources (#2215)

* feat(mcp): support mcp resources

* feat(web): split MCP resources into tab

* docs: add MCP resources PR review

* feat(mcp): productionize resource support

* feat(mcp): scope local agent tools and resources

* fix(web): gate space embedding models behind login

* fix(web): prevent clipped space model CTA

* test: update preproc resource tool expectations

* fix(web): expose skill authoring tools in selector

---------

Co-authored-by: yang.xiang <yang.xiang@advancegroup.com>
Co-authored-by: Hyu <chenhyu@proton.me>
Co-authored-by: Junyan Qin <rockchinq@gmail.com>
This commit is contained in:
advancer-young
2026-06-30 19:16:30 +08:00
committed by GitHub
parent 2618e06492
commit 096ec1a8ce
39 changed files with 4103 additions and 201 deletions
@@ -0,0 +1,278 @@
from __future__ import annotations
import base64
from types import SimpleNamespace
from unittest.mock import AsyncMock, Mock
import pytest
from mcp import types as mcp_types
from langbot.pkg.provider.tools.loaders.mcp import (
MCP_RESOURCE_CONTEXT_QUERY_KEY,
MCP_RESOURCE_TRACE_QUERY_KEY,
MCP_TOOL_LIST_RESOURCES,
MCP_TOOL_READ_RESOURCE,
MCPLoader,
MCPSessionStatus,
RuntimeMCPSession,
)
from langbot.pkg.telemetry import features as telemetry_features
def _app() -> SimpleNamespace:
return SimpleNamespace(logger=Mock())
def _connected_session(
*,
name: str = 'docs',
uuid: str = 'srv-1',
resources: list[dict] | None = None,
templates: list[dict] | None = None,
) -> RuntimeMCPSession:
session = RuntimeMCPSession(name, {'uuid': uuid, 'mode': 'remote'}, True, _app())
session.status = MCPSessionStatus.CONNECTED
session.session = SimpleNamespace(read_resource=AsyncMock())
session.resources = resources or [
{
'uri': 'file:///README.md',
'name': 'README.md',
'title': '',
'description': '',
'mime_type': 'text/markdown',
'size': None,
'icons': [],
'annotations': {},
'_meta': {},
}
]
session.resource_templates = templates or []
return session
def _query() -> SimpleNamespace:
return SimpleNamespace(variables={})
@pytest.mark.asyncio
async def test_read_resource_envelope_truncates_caches_and_records_trace():
session = _connected_session()
session.session.read_resource.return_value = mcp_types.ReadResourceResult(
contents=[
mcp_types.TextResourceContents(
uri='file:///README.md',
mimeType='text/markdown',
text='abcdef',
)
]
)
query = _query()
first = await session.read_resource_envelope(
'file:///README.md',
max_bytes=4,
source='ui_preview',
query=query,
)
second = await session.read_resource_envelope(
'file:///README.md',
max_bytes=4,
source='agent_tool',
query=query,
)
assert first['contents'][0]['text'] == 'abcd'
assert first['contents'][0]['bytes'] == 6
assert first['truncated'] is True
assert first['cache_hit'] is False
assert second['cache_hit'] is True
assert second['source'] == 'agent_tool'
assert session.session.read_resource.await_count == 1
traces = query.variables[MCP_RESOURCE_TRACE_QUERY_KEY]
assert [trace['source'] for trace in traces] == ['ui_preview', 'agent_tool']
assert traces[1]['cache_hit'] is True
assert query.variables[telemetry_features.FEATURES_KEY]['mcp_resource_reads'] == {
'ui_preview': 1,
'agent_tool': 1,
}
@pytest.mark.asyncio
async def test_read_resource_envelope_shares_byte_budget_across_text_contents():
session = _connected_session()
session.session.read_resource.return_value = mcp_types.ReadResourceResult(
contents=[
mcp_types.TextResourceContents(
uri='file:///README.md#first',
mimeType='text/plain',
text='abc',
),
mcp_types.TextResourceContents(
uri='file:///README.md#second',
mimeType='text/plain',
text='def',
),
]
)
envelope = await session.read_resource_envelope('file:///README.md', max_bytes=4)
assert [item['text'] for item in envelope['contents']] == ['abc', 'd']
assert envelope['contents'][0]['truncated'] is False
assert envelope['contents'][1]['truncated'] is True
assert envelope['bytes'] == 6
assert envelope['truncated'] is True
@pytest.mark.asyncio
async def test_read_resource_envelope_omits_binary_by_default():
session = _connected_session(
resources=[
{
'uri': 'file:///image.png',
'name': 'image.png',
'title': '',
'description': '',
'mime_type': 'image/png',
'size': 4,
'icons': [],
'annotations': {},
'_meta': {},
}
]
)
session.session.read_resource.return_value = mcp_types.ReadResourceResult(
contents=[
mcp_types.BlobResourceContents(
uri='file:///image.png',
mimeType='image/png',
blob=base64.b64encode(b'\x00\x01\x02\x03').decode(),
)
]
)
envelope = await session.read_resource_envelope('file:///image.png')
content = envelope['contents'][0]
assert content['type'] == 'blob'
assert content['blob'] is None
assert content['bytes'] == 4
assert content['binary_omitted'] is True
assert envelope['truncated'] is True
assert envelope['warnings'] == ['Binary resource content omitted from response.']
@pytest.mark.asyncio
async def test_read_resource_envelope_rejects_unlisted_uri():
session = _connected_session()
with pytest.raises(ValueError, match='Resource URI is not available'):
await session.read_resource_envelope('file:///secret.txt')
session.session.read_resource.assert_not_called()
def test_resource_uri_allowed_supports_listed_templates_conservatively():
session = _connected_session(
resources=[],
templates=[
{
'uri_template': 'repo://{owner}/{repo}/file/{path}',
'name': 'repository file',
'title': '',
'description': '',
'mime_type': 'text/plain',
'icons': [],
'annotations': {},
'_meta': {},
}
],
)
assert session.resource_uri_allowed('repo://langbot-app/LangBot/file/src/main.py') is True
assert session.resource_uri_allowed('repo://langbot-app/LangBot/issues/1') is False
assert session.resource_uri_allowed('https://example.com/secret') is False
@pytest.mark.asyncio
async def test_mcp_loader_can_hide_synthetic_resource_tools():
loader = MCPLoader(_app())
session = _connected_session()
loader.sessions = {'docs': session}
with_resource_tools = await loader.get_tools(['srv-1'], include_resource_tools=True)
without_resource_tools = await loader.get_tools(['srv-1'], include_resource_tools=False)
assert {tool.name for tool in with_resource_tools} == {
MCP_TOOL_LIST_RESOURCES,
MCP_TOOL_READ_RESOURCE,
}
assert without_resource_tools == []
@pytest.mark.asyncio
async def test_mcp_loader_refuses_resource_tool_calls_when_agent_read_disabled():
loader = MCPLoader(_app())
session = _connected_session()
loader.sessions = {'docs': session}
query = SimpleNamespace(
variables={
'_pipeline_bound_mcp_servers': ['srv-1'],
'_pipeline_mcp_resource_agent_read_enabled': False,
}
)
result = await loader.invoke_tool(
MCP_TOOL_READ_RESOURCE,
{'server_name': 'docs', 'uri': 'file:///README.md'},
query,
)
assert result[0].text == 'Error: MCP resource agent reads are disabled.'
session.session.read_resource.assert_not_called()
@pytest.mark.asyncio
async def test_build_resource_context_for_query_uses_only_bound_attached_text_resources():
loader = MCPLoader(_app())
docs = _connected_session(name='docs', uuid='srv-1')
docs.session.read_resource.return_value = mcp_types.ReadResourceResult(
contents=[
mcp_types.TextResourceContents(
uri='file:///README.md',
mimeType='text/markdown',
text='LangBot MCP resource context',
)
]
)
other = _connected_session(name='other', uuid='srv-2')
other.session.read_resource.return_value = mcp_types.ReadResourceResult(
contents=[
mcp_types.TextResourceContents(
uri='file:///README.md',
mimeType='text/markdown',
text='must not be injected',
)
]
)
loader.sessions = {'docs': docs, 'other': other}
query = SimpleNamespace(
variables={
'_pipeline_bound_mcp_servers': ['srv-1'],
'_pipeline_mcp_resource_attachments': [
{'server_uuid': 'srv-1', 'server_name': 'docs', 'uri': 'file:///README.md', 'mode': 'pinned'},
{'server_uuid': 'srv-2', 'server_name': 'other', 'uri': 'file:///README.md', 'mode': 'pinned'},
],
}
)
context = await loader.build_resource_context_for_query(query)
assert '<mcp_resource ' in context
assert 'server="docs"' in context
assert 'LangBot MCP resource context' in context
assert 'must not be injected' not in context
assert query.variables[MCP_RESOURCE_CONTEXT_QUERY_KEY]['resource_count'] == 1
docs.session.read_resource.assert_awaited_once()
other.session.read_resource.assert_not_called()
@@ -15,13 +15,35 @@ from langbot.pkg.provider.tools.toolmgr import ToolManager
class StubLoader:
def __init__(self, tools: list[resource_tool.LLMTool] | None = None, invoke_result=None):
def __init__(
self,
tools: list[resource_tool.LLMTool] | None = None,
invoke_result=None,
catalog_source: str = 'mcp',
catalog_source_name: str = 'fixture-server',
):
self._tools = tools or []
self._invoke_result = invoke_result
self._catalog_source = catalog_source
self._catalog_source_name = catalog_source_name
async def get_tools(self, *_args, **_kwargs):
return self._tools
async def get_tool_catalog(self, *_args, **_kwargs):
return [
{
'name': tool.name,
'description': tool.description,
'human_desc': tool.human_desc,
'parameters': tool.parameters,
'source': self._catalog_source,
'source_name': self._catalog_source_name,
'source_id': self._catalog_source_name,
}
for tool in self._tools
]
async def has_tool(self, name: str) -> bool:
return any(tool.name == name for tool in self._tools)
@@ -68,6 +90,28 @@ async def test_tool_manager_includes_skill_authoring_tools_when_requested():
assert [tool.name for tool in tools] == ['exec', 'activate', 'plugin_tool', 'mcp_tool']
@pytest.mark.asyncio
async def test_tool_manager_catalog_labels_tool_sources():
manager = ToolManager(SimpleNamespace())
manager.native_tool_loader = StubLoader([make_tool('exec')])
manager.skill_tool_loader = StubLoader([make_tool('activate')])
manager.plugin_tool_loader = StubLoader(
[make_tool('plugin_tool')],
catalog_source='plugin',
catalog_source_name='fixture-plugin',
)
manager.mcp_tool_loader = StubLoader([make_tool('mcp_tool')])
catalog = await manager.get_tool_catalog(include_skill_authoring=True)
assert [(item['name'], item['source'], item['source_name']) for item in catalog] == [
('exec', 'builtin', 'LangBot'),
('activate', 'skill', 'LangBot'),
('plugin_tool', 'plugin', 'fixture-plugin'),
('mcp_tool', 'mcp', 'fixture-server'),
]
@pytest.mark.asyncio
async def test_tool_manager_routes_native_tool_calls():
app = SimpleNamespace()