Skip to main content
cesteralDocs
FAQContact

Agent Node

Run a multi-step AI agent with access to tools and MCP connections

Last updated 8 Oct 2026

The Agent node runs an AI agent that can use built-in tools and connected MCP servers to complete multi-step tasks. Unlike the LLM node, the Agent node iterates in a reasoning loop — calling tools, observing results, and continuing until it produces a final answer (or hits a guardrail).

When to Use

Use Agent when a task requires multiple steps, tool calls, or decision-making that can't be expressed as a single prompt — for example: researching a company, drafting a personalized email, and then revising it based on a compliance check.

Configuration

The agent runs once per input record, resolving {{field}} placeholders against that record.

FieldTypeDescription
provideropenai | anthropic | google | groqLLM provider (default: anthropic)
modelstringModel ID
credentialIdstringLLM credential to use. Leave blank to use the platform-managed key (subject to your plan)
systemPromptstringAgent instructions. Supports {{variable}} syntax
userPromptTemplatestringPer-record user message. Supports {{variable}} syntax
outputColumnstringField to write the agent's final response to (default: agent_output)
outputModetext | json_schemaWhether to return free text or schema-validated JSON
outputSchemaobjectJSON Schema for structured output (used when outputMode: json_schema)
reasoningTypestringReasoning strategy that wraps the system prompt with chain-of-thought / structured-process guidance (direct is a no-op)
builtInScopesstring[]Built-in MCP tool scopes to enable (e.g., ["census:read", "http:use"])
builtInToolNamesstring[]Restrict to specific built-in tool names (a filter within builtInScopes, not an additive source)
externalConnectionIdsstring[]IDs of external MCP connections available to the agent
workflowToolIdsstring[]Automation IDs to expose to the agent as callable tools
maxIterationsnumberMaximum reasoning iterations per record
maxToolCallsnumberMaximum total tool calls per record
costCapPerRownumberMaximum estimated LLM cost in USD per record before aborting
timeoutPerRownumberPer-record timeout
continueOnErrorbooleanIf true, failed records are emitted with an error field rather than failing the run (default: false)
trustLevelstringGovernance trust level applied to the agent's tool calls

Example

Research and summarize each company:

provider: anthropic
model: claude-sonnet-4-6
systemPrompt: "You are a B2B research analyst. Research companies thoroughly and provide structured summaries."
userPromptTemplate: "Research {{company_name}} ({{domain}}). Summarize: industry, key products, recent news, and competitive position."
maxIterations: 15
costCapPerRow: 0.25
builtInScopes: [census:read, http:use]
outputColumn: company_research
continueOnError: true

Notes

  • Agent tool calls run on the governed MCP rail — guardrails are evaluated and the run is logged to the audit trail.
  • costCapPerRow is an approximate guard based on token estimation — actual costs may vary slightly.
  • Once maxIterations (or maxToolCalls) is reached, the agent stops and returns its best answer so far.
  • External MCP connections must be configured under Settings → Integrations before they can be referenced in externalConnectionIds.
  • Leaving credentialId blank uses the platform-managed provider key; frontier models may require a paid plan.

Related articles

Still stuck? Browse the FAQ or contact us.