What Makes Up an Agent
Every agent consists of:- Prompts - The instructions sent to the agent
- Engine - The AI coding CLI that powers the agent
- Model - The AI model the engine uses
- Interactivity - Whether the agent waits for input or runs automatically
- MCP - External tools and integrations available to the agent
Agent Types
Main Agent
Runs as a step in the workflow. Does the primary work.
Module
A main agent that can loop back to earlier steps.
Sub-agent
Spawned by main agents via MCP to delegate work.
Controller
Orchestrates on your behalf - answers questions, signals next steps.
When to Use Each Type
Main Agent
Use for standard workflow steps that run once and pass output forward.Best for
Best for
- Single-pass tasks (analysis, generation, implementation)
- Steps that don’t need to revisit previous work
- Most workflow steps
Configure Main Agents
Learn how to set up main agents
Module
Use when a step needs to loop back based on results.Best for
Best for
- Review and revision cycles
- Iterative refinement
- Quality gates that may require rework
Configure Modules
Learn how to set up modules
Sub-agent
Use to break complex work into delegated tasks within a single step.Best for
Best for
- Parallel task execution
- Context isolation
- Specialized subtasks
Sub-agents are not steps. They are a context management tool for delegating work between agents.
Configure Sub-agents
Learn how to set up sub-agents
Controller
Use for autonomous workflows where you want an agent to make decisions between steps.Best for
Best for
- Long-running autonomous workflows
- Tasks where you want to review results, not manage process
- Complex multi-step operations with clear objectives
Configure Controllers
Learn how to set up controllers
Agent vs Step
| Concept | What It Is |
|---|---|
| Step | A position in the workflow sequence |
| Agent | The AI session that executes at that position |
Engines
An engine is an AI coding CLI that powers the agent. Different engines have different capabilities, strengths, and supported models. Why this matters: You can mix engines in a single workflow—use one engine for creative tasks, another for complex reasoning, and a fast one for simple operations.Configure Engines & Models
See available engines, model options, and configuration examples
Interactivity
Interactivity determines whether an agent waits for input or proceeds automatically.- Interactive
- Non-Interactive
Agent waits for user input.
- Pauses after each prompt
- User reviews and responds
- Best for exploration and Q&A
This is how hybrid workflows work - some agents wait for you, others run automatically.
Configure Interactivity
Learn how to set interactive or non-interactive mode per agent
MCP
MCP (Model Context Protocol) servers extend agent capabilities with additional tools. What MCP provides:- Custom tool integrations
- External data access
- Sub-agent spawning
- Signals for workflow control
The signals MCP is required for autonomous workflows where agents need to communicate with the controller. It’s also required when using sub-agents, since agent coordination works through MCP.
Configure MCP
Learn how to add MCP servers to your agents
Prompts
Prompts are the instructions sent to an agent. They define what the agent should do.Chained Prompts
Multiple prompts injected into the same agent session, one after another. Instead of overwhelming one step with all instructions, you break it into smaller sequential prompts. Example flow:- First prompt: “Analyze the codebase structure”
- User reviews output
- Second prompt: “Based on your analysis, identify potential issues”
- User reviews output
- Third prompt: “Create a plan to address the top 3 issues”
Same agent, same session. Prompts run in sequence. Common in interactive Q&A workflows.
Configure Chained Prompts
Learn how to set up sequential prompts for an agent
Placeholders
Placeholders inject data into agent prompts.| Type | Source | Use case |
|---|---|---|
| Static (packageDir) | Pre-defined prompts from workflow package | Shared prompts, split large prompts |
| Dynamic (userDir) | Files created during workflow | Agent A outputs a file, Agent B receives it |
Configure Placeholders
Learn how to use static and dynamic placeholders in prompts
Directives
Directives allow agents to control the workflow by writing to a JSON file. The workflow listens after each step and takes action.| Directive | Action |
|---|---|
checkpoint | Shows message to user, option to continue or stop |
stop | Stops the workflow |
error | Shows error message and stops |
pause | Pauses and waits for user input |
loop | Returns back to a previous step (modules only) |
trigger | Triggers any agent in the workflow (modules only) |
Directives come from agents. Signals come from users. Both control execution, but from different sources.
Configure Directives
Learn how to enable agents to control workflow execution