LangBot/plugins/Runner/langflow-agent/README.md

Langflow Agent

Tweaks must be a JSON object (a JSON string or an object). Missing, null, empty, or whitespace-only input means no overrides. Invalid JSON and other values fail with langflow.config_invalid without logging the payload. Whitespace-only input is a plugin convenience; native Langflow rejected it. Conversation history remains persistent through external.session_id; migration does not restore the native fresh-session-per-request behavior.

Run a Langflow flow as a LangBot Runner.

Runner ID

plugin:langbot-team/LangflowAgent/default

Configuration

Field	Type	Required	Default	Description
base-url	string	yes	http://localhost:7860	Langflow server URL
api-key	secret	yes	''	Langflow API key
flow-id	string	yes	''	Flow ID
advanced-settings	boolean	no	false	Show input, output, and flow tweak controls
input-type	string	no	chat	Input type
output-type	string	no	chat	Output type
tweaks	json	no	{}	Flow tweaks
langbot-assets-enabled	boolean	no	false	Register a short-lived LangBot asset token for each run and inject it into the flow via a tweak
langbot-assets-gateway-host	string	no	0.0.0.0	Host for the local LangBot Asset Gateway
langbot-assets-gateway-port	integer	no	8765	Port for the local LangBot Asset Gateway
langbot-assets-gateway-request-timeout	integer	no	60	Timeout for individual gateway tool calls
langbot-assets-token-ttl	integer	no	3600	Lifetime of each run token in seconds
langbot-assets-input-name	string	no	langbot_asset_run_token	Flow component (name/id) whose input_value receives the run token

LangBot Asset Callback Through Langflow MCP Tools

Langflow can call back into LangBot assets through the SDK Asset Gateway, the same mechanism the Dify runner uses. The gateway is a run-token-authorized MCP server (POST /mcp, JSON-RPC) exposing the run-authorized LangBot tools: langbot_list_assets, langbot_get_current_event, langbot_history_page, langbot_retrieve_knowledge, langbot_get_tool_detail, and langbot_call_tool.

How it works

1. When langbot-assets-enabled is true, this runner registers a short-lived, run-scoped token before calling the flow and injects it into the run via a tweak: it sets the input_value of the component named by langbot-assets-input-name (default langbot_asset_run_token) to the token.
2. The flow's Agent reads that value and passes it as the run_token argument on every LangBot MCP tool call.
3. The runner removes the token when the run ends. Tool calls without a valid token are rejected by the gateway.

The gateway accepts the token via an Authorization: Bearer header or via a run_token tool-call argument. Use the run_token argument approach here.

Build the flow

1. Add a Text Input (or similar) component whose name/id matches langbot-assets-input-name. The runner sets its input_value to the token each run. (Leave its value empty by default.)

2. Add an MCP Tools / MCP Connection component:

   • Transport: streamable HTTP.
   • URL: the public URL routing to the gateway /mcp, e.g. https://example.com/mcp.

3. Add an Agent component, attach the MCP Tools, and wire the token component into the Agent so its instructions pass run_token on every LangBot tool call, for example:

   For every LangBot MCP tool call, set run_token exactly to the provided
   LangBot run token. Call langbot_list_assets first to discover available
   LangBot assets for the current run.
   

Configure LangBot

Select the Langflow runner and set:

base-url = http://localhost:7860
api-key = <Langflow API key>
flow-id = <flow id>
langbot-assets-enabled = true
langbot-assets-gateway-host = 0.0.0.0
langbot-assets-gateway-port = 8765
langbot-assets-token-ttl = 3600
langbot-assets-input-name = langbot_asset_run_token

The public MCP URL in the flow's MCP component must route to this same gateway instance. The runner only injects the short-lived token into the flow tweak; it does not create or update the flow's MCP component.

Limitations

• A remote/cloud Langflow that cannot reach localhost needs a public HTTPS URL for the gateway /mcp endpoint.
• The run token is short-lived and run-scoped; the flow must complete its asset callbacks within the flow run.
• The gateway exposes only the assets permitted by the current run: current event, history page, knowledge retrieval, tool detail, and tool call.
• The flow must have a component whose name/id matches langbot-assets-input-name for the tweak injection to land; otherwise the token never reaches the Agent. Verify the tools/list handshake against your gateway when setting this up.

Legacy Runner

Migrated from langflow-api in LangBot.

Dedicated runtime placement

This release is unsigned and dedicated. Historical shared-runtime notes in SHARED_RUNTIME.md do not grant shared-worker eligibility.