# Agent Compilation: YAML Source → Final Agent
> **For the LLM running this workflow:** This document explains what the compiler adds. When building agents, focus on the YAML structure defined here—do NOT add things the compiler handles automatically.
>
> **Example reference:** Compare `{workflow_path}/data/reference/module-examples/architect.agent.yaml` (source, 32 lines) with `architect.md` (compiled, 69 lines) to see what the compiler adds.
---
## Quick Overview
You write: **YAML source file** (`agent-name.agent.yaml`)
Compiler produces: **Markdown with XML** (`agent-name.md`) for LLM consumption
The compiler transforms your clean YAML into a fully functional agent by adding:
- Frontmatter (name, description)
- XML activation block with numbered steps
- Menu handlers (workflow, exec, action)
- Auto-injected menu items (MH, CH, PM, DA)
- Rules section
---
## What YOU Provide (YAML Source)
Your YAML contains ONLY these sections:
```yaml
agent:
metadata:
id: "_bmad/..."
name: "Persona Name"
title: "Agent Title"
icon: "🔧"
module: "stand-alone" or "bmm" or "cis" or "bmgd"
persona:
role: "First-person role description"
identity: "Background and specializations"
communication_style: "How the agent speaks"
principles:
- "Core belief or methodology"
critical_actions: # Optional - for Expert agents only
- "Load ./sidecar/memories.md"
- "Load ./sidecar/instructions.md"
- "ONLY access ./sidecar/"
prompts: # Optional - for Simple/Expert agents
- id: prompt-name
content: |
Prompt content
menu: # Your custom items only
- trigger: XX or fuzzy match on command-name
workflow: "path/to/workflow.yaml" # OR
exec: "path/to/file.md" # OR
action: "#prompt-id"
description: "[XX] Command description"
```
---
## What COMPILER Adds (DO NOT Include)
### 1. Frontmatter
```markdown
---
name: "architect"
description: "Architect"
---
```
**DO NOT add** frontmatter to your YAML.
### 2. XML Activation Block
```xml
Load persona from this current agent file
Load config to get {user_name}, {communication_language}
Remember: user's name is {user_name}
ALWAYS communicate in {communication_language}
Show greeting + numbered menu
STOP and WAIT for user input
Input resolution rules
...
...
```
**DO NOT create** activation sections—the compiler builds them.
### 3. Auto-Injected Menu Items
Every agent gets these 4 items automatically. **DO NOT add them to your YAML:**
| Code | Trigger | Description |
|------|---------|-------------|
| MH | menu or help | Redisplay Menu Help |
| CH | chat | Chat with the Agent about anything |
| PM | party-mode | Start Party Mode |
| DA | exit, leave, goodbye, dismiss agent | Dismiss Agent |
### 4. Menu Handlers
```xml
When menu item has: workflow="path/to/workflow.yaml"
→ Load workflow.xml and execute with workflow-config parameter
When menu item has: exec="path/to/file.md"
→ Load and execute the file at that path
```
**DO NOT add** handlers—the compiler detects and generates them.
---
## Before/After Example: Architect Agent
### Source: `architect.agent.yaml` (32 lines - YOU WRITE)
```yaml
agent:
metadata:
id: "_bmad/bmm/agents/architect.md"
name: Winston
title: Architect
icon: 🏗️
module: bmm
persona:
role: System Architect + Technical Design Leader
identity: Senior architect with expertise in distributed systems...
communication_style: "Speaks in calm, pragmatic tones..."
principles: |
- User journeys drive technical decisions...
menu:
- trigger: WS or fuzzy match on workflow-status
workflow: "{project-root}/_bmad/bmm/workflows/workflow-status/workflow.yaml"
description: "[WS] Get workflow status..."
- trigger: CA or fuzzy match on create-architecture
exec: "{project-root}/_bmad/bmm/workflows/3-solutioning/create-architecture/workflow.md"
description: "[CA] Create an Architecture Document"
- trigger: IR or fuzzy match on implementation-readiness
exec: "{project-root}/_bmad/bmm/workflows/3-solutioning/check-implementation-readiness/workflow.md"
description: "[IR] Implementation Readiness Review"
```
### Compiled: `architect.md` (69 lines - COMPILER PRODUCES)
```markdown
---
name: "architect"
description: "Architect"
---
You must fully embody this agent's persona...
```xml
Load persona from this current agent file (already in context)
🚨 IMMEDIATE ACTION REQUIRED - BEFORE ANY OUTPUT...
Remember: user's name is {user_name}
Show greeting using {user_name} from config...
STOP and WAIT for user input...
On user input: Number → execute menu item[n]...
When executing a menu item: Check menu-handlers section...
...
...
ALWAYS communicate in {communication_language}
Stay in character until exit selected
Display Menu items as the item dictates...
Load files ONLY when executing menu items...
System Architect + Technical Design Leader
Senior architect with expertise...
Speaks in calm, pragmatic tones...
- User journeys drive technical decisions...
```
**Key additions by compiler:** Frontmatter, activation block, handlers, rules, MH/CH/PM/DA menu items.
---
## DO NOT DO Checklist
When building agent YAML, **DO NOT:**
- [ ] Add frontmatter (`---name/description---`) to YAML
- [ ] Create activation blocks or XML sections
- [ ] Add MH (menu/help) menu item
- [ ] Add CH (chat) menu item
- [ ] Add PM (party-mode) menu item
- [ ] Add DA (dismiss/exit) menu item
- [ ] Add menu handlers (workflow/exec logic)
- [ ] Add rules section
- [ ] Duplicate any auto-injected content
**DO:**
- [ ] Define metadata (id, name, title, icon, module)
- [ ] Define persona (role, identity, communication_style, principles)
- [ ] Define critical_actions (Expert agents only)
- [ ] Define prompts with IDs (Simple/Expert agents only)
- [ ] Define menu with your custom items only
- [ ] Use proper trigger format: `XX or fuzzy match on command-name`
- [ ] Use proper description format: `[XX] Description text`
---
## Expert Agent: critical_actions
For Expert agents with sidecars, your `critical_actions` become activation steps:
```yaml
critical_actions:
- "Load COMPLETE file ./agent-sidecar/memories.md"
- "Load COMPLETE file ./agent-sidecar/instructions.md"
- "ONLY read/write files in ./agent-sidecar/"
```
The compiler injects these as steps 4, 5, 6 in the activation block:
```xml
Load COMPLETE file ./agent-sidecar/memories.md
Load COMPLETE file ./agent-sidecar/instructions.md
ONLY read/write files in ./agent-sidecar/
ALWAYS communicate in {communication_language}
```
---
## Division of Responsibilities
| Aspect | YOU Provide (YAML) | COMPILER Adds |
|--------|-------------------|---------------|
| Agent identity | metadata + persona | Wrapped in XML |
| Memory/actions | critical_actions | Inserted as activation steps |
| Prompts | prompts with IDs | Referenced by menu actions |
| Menu items | Your custom commands only | + MH, CH, PM, DA (auto) |
| Activation | — | Full XML block with handlers |
| Rules | — | Standardized rules section |
| Frontmatter | — | name/description header |
---
## Quick Reference for LLM
- **Focus on:** Clean YAML structure, persona definition, custom menu items
- **Ignore:** What happens after compilation—that's the compiler's job
- **Remember:** Every agent gets MH, CH, PM, DA automatically—don't add them
- **Expert agents:** Use `critical_actions` for sidecar file loading
- **Module agents:** Use `workflow:` or `exec:` references, not inline actions