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Overview

This document covers the variable system used across all agent types. Variables enable dynamic data flow so you can capture, transform, and use data in your conversational agents. Applies to:
  • Flow Builder Agents: Multi-node workflows with variable extraction (AI, toolpath, DTMF), static variables, and flow logic
  • Single Prompt Agents: Standalone conversational agents with a simplified variable model (system + custom only)
Variables provide context, enable personalization, and allow data to flow between parts of your agent—whether across nodes in a flow or within a single prompt configuration.

Quick Start: Tool Testing & Variable Extraction

The steps below apply to Flow Builder agents only (tool nodes and variable extraction). Single prompt agents use only system and custom variables—see Single Prompt Agent Variables and Example 6: Single Prompt Agent.

For API Tool Nodes (Flow Builder)

  1. ⚙️ Configure Tool → Set up endpoint, headers, parameters
  2. 🧪 Test Tool → Click “Test Tool” to run with real data
  3. Verify Response → Confirm the tool returns the expected shape
  4. 📤 Extract Variables → Use the path selector with the test response
  5. 👁️ Preview Values → Check that extracted values are correct
  6. 💾 Save → Variables are available to successor nodes
Why this matters: Validates the API before deployment, avoids JSONPath mistakes, and surfaces issues at design time.

For Web Tool Nodes (Flow Builder)

  1. ⚙️ Configure Web Tool → Set up browser instructions and actions
  2. 📋 Define Expected Response → Paste or type the expected structure (JSON object or string)
  3. 📤 Extract Variables → Use the path selector against that expected structure
  4. 👁️ Preview Values → Confirm extraction paths
  5. 🧪 Manually Verify → Run the web tool to confirm the real response format
  6. 💾 Save → Variables are available to successor nodes
Why this matters: Documents the response contract, supports JSON and string responses, and lets you use the path selector without server-side testing.
Important
  • API tools: Test before configuring extraction; the path selector uses the actual test response.
  • Web tools: Define the expected response; the path selector validates against that format.

Variable Architecture

The system has four main categories:
CategoryFlow Builder AgentsSingle Prompt AgentsDescription
System VariablesPlatform-provided, always available (15+ variables)
Custom Variables✅ (as params)Workflow-level; in single-prompt, converted to params
Extracted VariablesFrom nodes (AI, toolpath, DTMF)—flow only
Static VariablesNode-level, fixed or templated—flow only
Next steps: