{ "checker": { "claims": [ { "claim": "Langflow flows are exposed as MCP tools that an MCP client can call", "command": "/tmp/lf-venv/bin/langflow run tools/call {\"tool\": \"coldpass_probe\", \"arguments\": {\"input_value\": \"hello coldpass\"}}", "evidence": "hello coldpass\"}], \"isError\": false}", "expected": "tool result echoes the input text", "input": "{\"tool\": \"coldpass_probe\", \"arguments\": {\"input_value\": \"hello coldpass\"}}", "kind": "claim", "outcome": "Real input produced the expected result: hello coldpass", "source": "**Deploy as an MCP server** and turn your flows into tools for MCP clients.", "source_checked": true, "source_file": "README.md", "verdict": "yes" } ], "cycle_checks": [ { "claim": "Scheduled or looping main behavior", "command": "", "evidence": "Entry points inspected: no cron, scheduler, --once or --now in src/backend/base/langflow; the only long-running loop is 'langflow listeners', which holds external provider connections (Slack Socket Mode, Microsoft Graph polling, Gmail Pub/Sub) and needs real provider credentials, so it was not exercised. The product webhook endpoints need external callers.", "expected": "identify the product trigger", "input": "source inspection", "kind": "cycle", "outcome": "Entry points inspected: no cron, scheduler, --once or --now in src/backend/base/langflow; the only long-running loop is 'langflow listeners', which holds external provider connections (Slack Socket Mode, Microsoft Graph polling, Gmail Pub/Sub) and needs real provider credentials, so it was not exercised. The product webhook endpoints need external callers.", "source": "repository entry points", "verdict": "yes" } ], "details": { "argv": [ "/tmp/lf-venv/bin/langflow", "run" ], "hosting": "local", "kind": "mcp_http", "protocolVersion": "2025-06-18", "scope": "remote hosted MCP initialize + tools/list", "serverInfo": { "name": "langflow-mcp-project-cc3bdc6e-d539-490a-a3d9-cafbe628b89c", "version": "1.30.0" }, "tool_result": { "content": [ { "text": "hello coldpass", "type": "text" } ], "isError": false }, "tool_result_checked": true, "tool_schema_bytes": 363, "tools": [ "coldpass_probe" ], "transport": "streamable-http", "url": "http://127.0.0.1:7860/api/v1/mcp/project/cc3bdc6e-d539-490a-a3d9-cafbe628b89c/streamable", "working": true }, "evidence_strength": "readme_checked", "example_checks": [ { "claim": "Install Langflow locally from PyPI (README Quickstart)", "command": "", "deferred": false, "evidence": "Not run as an example; the install step was executed directly: uv pip install langflow -U in a fresh venv (/tmp/lf-venv, Python 3.12.3). No documented example command in the README was runnable as a finite example.", "expected": "documented command completes successfully", "input": "", "kind": "example", "outcome": "Not run as an example; the install step was executed directly: uv pip install langflow -U in a fresh venv (/tmp/lf-venv, Python 3.12.3). No documented example command in the README was runnable as a finite example.", "source": "README.md Quickstart > Install locally", "verdict": "blocked" } ], "status": "PASS" }, "deviations": [ "uv was not preinstalled; installed with the official uv install.sh (curl|sh) into ~/.local.", "README 'uv run langflow run' was not used from the checkout; the PyPI package was installed in a venv per the README install step and run via the absolute path /tmp/lf-venv/bin/langflow run. The checkout source (also version 1.13.0) was not built or run.", "Release packages disable auto login, so LANGFLOW_SUPERUSER_PASSWORD was set to a throwaway local value in the guest.", "The project MCP endpoint rejected the Bearer JWT and required an x-api-key header, so the probe passes x-api-key instead of Authorization.", "The empty flow returned no MCP content; a ChatInput node built from the product's own component catalog (/api/v1/all) and an edge to a ChatOutput node were added before the tool call returned text.", "The README has no runnable example or test command for the quickstart; the example entry is recorded with reason. The Makefile unit test suite was not run.", "The checker path /inputs/coldpass-preflight.py does not exist in this guest; the checker at was used instead.", "Git init/fetch was not performed; the workspace is not a git repository and the checker ran without it.", "A broad pkill matched my own shell command once; the server was then stopped by PID and port 7860 confirmed free before replay." ], "fault_owner": null, "main_blocker": null, "operation": "Install Langflow 1.13.0 from PyPI per the README Quickstart, start the server, create a flow via the REST API, expose it as an MCP tool, and call that tool over streamable HTTP; the tool returned 'hello coldpass'.", "operation_scope": "Local Linux guest (Ubuntu 24.04, Python 3.12.3, uv 0.13.5), no browser, no external providers. Auth: ", "outcome": "working", "plain_failure": null, "steps": [ "curl -LsSf https://astral.sh/uv/install.sh | sh", "uv venv /tmp/lf-venv --python 3.12 (run from fresh dir /tmp/lf-fresh)", "uv pip install langflow -U (README: 'uv pip install langflow -U', run in a fresh directory)", "langflow run (README: 'uv run langflow run'; started as /tmp/lf-venv/bin/langflow run with DO_NOT_TRACK=true and LANGFLOW_SUPERUSER_PASSWORD set)", "POST /api/v1/login, POST /api/v1/flows/, PATCH /api/v1/flows/{id} (mcp_enabled=true), POST /api/v1/api_key/", "POST /api/v1/run/{flow_id} echoed 'hello coldpass' through ChatInput->ChatOutput", "MCP streamable HTTP initialize, tools/list (coldpass_probe), tools/call -> 'hello coldpass'", "python3 -I --validate --replay -> valid, replay PASS" ], "stuck_step": null, "suggested_fix": "None for the tested path. Optional: the checkout's own source run path (make run_cli / uv run langflow run from the repo) was not exercised." }