fix(pipeline): decouple Runner from extension permissions (LANG-54) (#2723)

* fix(pipeline): decouple runner from extension allowlist

Co-authored-by: multica-agent <[email protected]>

* fix(pipeline): complete runner diagnostics and real runtime coverage

Co-authored-by: multica-agent <[email protected]>

---------

Co-authored-by: multica-agent <[email protected]>

src/langbot/pkg/agent/runner/registry.py

@@ -14,7 +14,7 @@ from ...api.http.context import ExecutionContext
 from ...api.http.service.tenant import TenantContext
 from .descriptor import RunnerDescriptor
 from .id import parse_runner_id, format_runner_id
-from .errors import RunnerNotFoundError, RunnerNotAuthorizedError
+from .errors import RunnerNotFoundError
 
 
 class RunnerRegistry:
@@ -229,14 +229,13 @@ class RunnerRegistry:
 
         Args:
             runner_id: Runner ID to lookup
-            bound_plugins: Optional bound plugins filter
+            bound_plugins: Legacy pipeline extension filter; does not authorize Runners.
 
         Returns:
             RunnerDescriptor
 
         Raises:
             RunnerNotFoundError: If runner not found
-            RunnerNotAuthorizedError: If runner not in bound plugins
         """
         # Parse and validate runner ID format
         try:
@@ -259,11 +258,9 @@ class RunnerRegistry:
         if descriptor is None:
             raise RunnerNotFoundError(runner_id)
 
-        # Check authorization
-        if bound_plugins is not None:
-            plugin_id = descriptor.get_plugin_id()
-            if plugin_id not in bound_plugins:
-                raise RunnerNotAuthorizedError(runner_id, bound_plugins)
+        # A selected Runner is independent of the pipeline extension allowlist.
+        # Installation enablement and Workspace scope are enforced by the connector
+        # again at invocation; never widen the extension permissions on the query.
 
         return descriptor
 

src/langbot/pkg/api/http/service/pipeline.py

@@ -189,7 +189,8 @@ class PipelineService:
         pipeline_data['stages'] = default_stage_order.copy()
         pipeline_data['is_default'] = default
 
-        pipeline_data['config'] = await self.get_default_pipeline_config(context)
+        if 'config' not in pipeline_data:
+            pipeline_data['config'] = await self.get_default_pipeline_config(context)
         RunnerConfigResolver.validate_pipeline_config(pipeline_data['config'])
 
         # Ensure extensions_preferences is set with enable_all_plugins and enable_all_mcp_servers=True by default

src/langbot/pkg/api/mcp/server.py

@@ -132,7 +132,13 @@ class LangBotMCPServer:
                 await ap.pipeline_service.get_pipeline_extensions(_authorized(Permission.RESOURCE_VIEW), pipeline_uuid)
             )
 
-        @mcp.tool(description='Replace all Pipeline extension bindings. All binding lists and switches are required.')
+        @mcp.tool(
+            description=(
+                'Replace all Pipeline extension bindings. All binding lists and switches are required. '
+                'Plugin switches control EventListener, Tool and Command only, not the independently selected Runner. '
+                'Do not add a Runner plugin here just to run it; installation, global enablement and Workspace access still apply.'
+            )
+        )
         async def update_pipeline_extensions(
             pipeline_uuid: str,
             bound_plugins: list[dict],
@@ -394,7 +400,8 @@ class LangBotMCPServer:
         @mcp.tool(
             description=(
                 'Create a pipeline. `pipeline_data` matches the LangBot POST '
-                '/api/v1/pipelines body. Returns the new pipeline UUID.'
+                '/api/v1/pipelines body. Supplied config and extension preferences are preserved; '
+                'omitting config uses installed Runner defaults. Returns the new pipeline UUID.'
             )
         )
         async def create_pipeline(pipeline_data: dict) -> str: