Fixed Response Agent

The Fixed Response Agent returns a single, statically configured string exactly as you supply it — with no LLM call. You give it a template string and it echoes that string straight back. It exists so a workflow can inject static content (a canned reply, a block of JSON, a set of expression templates, a constant configuration) into a pipeline without paying for or waiting on a model completion.

It belongs to the Custom Agents group: a set of pre-built, externally dispatched agents you select by ID instead of configuring an LLM loop yourself. Like every agent in this group, it runs as a Custom agent (custom_agent) — the agent service forwards the node's inputs to the custom-action service, which executes the agent and returns its output. See Custom Agent for how the custom_agent dispatch mechanism works.

Availability. This agent is enabled in all environments (local, development, staging, and production).

When to use it

Use the Fixed Response Agent whenever a node in a workflow needs to emit a constant value:

Feed a fixed block of configuration (such as the expression_templates consumed by the Criteria Expression Builder) into a downstream node.
Return a canned message or boilerplate response without invoking a model.
Stand in as a deterministic placeholder while you build out the rest of a workflow.

Because there is no model call, the agent is instantaneous, deterministic, and reports no token usage.

Configuration

Add the agent to a workflow as a Custom agent and pin it by ID in agent_config.type_config:

{ "custom_agent_id": "fixed_response_agent" }

It reads exactly one input key.

Input key	Required	Purpose
`template`	Yes	The static string to return verbatim. May be any text, including a serialized JSON string. When empty or omitted, the agent returns an empty string.

The template value is returned byte-for-byte; the agent does not parse, validate, or transform it.

Output

The agent returns an object with a single key whose value is the template, unchanged:

{ "fixed_response_with_sources": "<your template, verbatim>" }

A downstream node reads the value via {{<node_id>.output.fixed_response_with_sources}}.

Example

A node configured as:

{ "custom_agent_id": "fixed_response_agent" }

with this input:

{ "template": "Thanks for reaching out. A specialist will follow up within one business day." }

returns:

{ "fixed_response_with_sources": "Thanks for reaching out. A specialist will follow up within one business day." }

To pass a JSON payload to a later node, set template to a serialized JSON string and let the consuming node parse it:

{ "template": "{\"state_id_object\": {\"US-CA\": \"California\"}}" }

What's next

Custom Agent — how the custom_agent dispatch this agent runs on works.
Criteria Expression Builder — a common consumer of a fixed expression_templates block.
Agent Reference overview — the agent-type model, catalog, and shared execution engine.