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)
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)
- ⚙️ Configure Tool → Set up endpoint, headers, parameters
- 🧪 Test Tool → Click “Test Tool” to run with real data
- ✅ Verify Response → Confirm the tool returns the expected shape
- 📤 Extract Variables → Use the path selector with the test response
- 👁️ Preview Values → Check that extracted values are correct
- 💾 Save → Variables are available to successor nodes
For Web Tool Nodes (Flow Builder)
- ⚙️ Configure Web Tool → Set up browser instructions and actions
- 📋 Define Expected Response → Paste or type the expected structure (JSON object or string)
- 📤 Extract Variables → Use the path selector against that expected structure
- 👁️ Preview Values → Confirm extraction paths
- 🧪 Manually Verify → Run the web tool to confirm the real response format
- 💾 Save → Variables are available to successor nodes
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:| Category | Flow Builder Agents | Single Prompt Agents | Description |
|---|---|---|---|
| System Variables | ✅ | ✅ | Platform-provided, always available (15+ variables) |
| Custom Variables | ✅ | ✅ (as params) | Workflow-level; in single-prompt, converted to params |
| Extracted Variables | ✅ | ❌ | From nodes (AI, toolpath, DTMF)—flow only |
| Static Variables | ✅ | ❌ | Node-level, fixed or templated—flow only |
- System Variables — Time, call, user, and agent variables
- Custom Variables — Workflow-level variables for both agent types
- Extracted Variables — AI, toolpath, and DTMF extraction (flow only)
- Static Variables — Node-level values (flow only)
- Availability & Context — Where each type is available, including Single Prompt Agent Variables