content-builder-agent

Content Builder Agent

A content writing agent for writing blog posts, LinkedIn posts, and tweets with cover images included.

This example demonstrates how to define an agent through three filesystem primitives:

• Memory (AGENTS.md) – persistent context like brand voice and style guidelines
• Skills (skills/*/SKILL.md) – workflows for specific tasks, loaded on demand
• Subagents (subagents.yaml) – specialized agents for delegated tasks like research

The content_writer.py script shows how to combine these into a working agent.

Quick Start

# Set API keys
export ANTHROPIC_API_KEY="..."
export GOOGLE_API_KEY="..."      # For image generation
export TAVILY_API_KEY="..."      # For web search (optional)

# Run (uv automatically installs dependencies on first run)
cd examples/content-builder-agent
uv run python content_writer.py "Write a blog post about prompt engineering"

More examples:

uv run python content_writer.py "Create a LinkedIn post about AI agents"
uv run python content_writer.py "Write a Twitter thread about the future of coding"

How It Works

The agent is configured by files on disk, not code:

content-builder-agent/
├── AGENTS.md                    # Brand voice & style guide
├── subagents.yaml               # Subagent definitions
├── skills/
│   ├── blog-post/
│   │   └── SKILL.md             # Blog writing workflow
│   └── social-media/
│       └── SKILL.md             # Social media workflow
└── content_writer.py            # Wires it together (includes tools)

File	Purpose	When Loaded
AGENTS.md	Brand voice, tone, writing standards	Always (system prompt)
subagents.yaml	Research and other delegated tasks	Always (defines task tool)
skills/*/SKILL.md	Content-specific workflows	On demand

What's in the skills? Each skill teaches the agent a specific workflow:

• Blog posts: Structure (hook → context → main content → CTA), SEO best practices, research-first approach
• Social media: Platform-specific formats (LinkedIn character limits, Twitter thread structure), hashtag usage
• Image generation: Detailed prompt engineering guides with examples for different content types (technical posts, announcements, thought leadership)

Architecture

agent = create_deep_agent(
    memory=["./AGENTS.md"],                        # ← Middleware loads into system prompt
    skills=["./skills/"],                          # ← Middleware loads on demand
    tools=[generate_cover, generate_social_image], # ← Image generation tools
    subagents=load_subagents("./subagents.yaml"),  # ← See note below
    backend=FilesystemBackend(root_dir="./"),
)

The memory and skills parameters are handled natively by deepagents middleware. Tools are defined in the script and passed directly.

Note on subagents: Unlike memory and skills, subagents must be defined in code. We use a small load_subagents() helper to externalize config to YAML. You can also define them inline:

subagents=[
    {
        "name": "researcher",
        "description": "Research topics before writing...",
        "model": "anthropic:claude-haiku-4-5-20251001",
        "system_prompt": "You are a research assistant...",
        "tools": [web_search],
    }
],

Flow:

1. Agent receives task → loads relevant skill (blog-post or social-media)
2. Delegates research to researcher subagent → saves to research/
3. Writes content following skill workflow → saves to blogs/ or linkedin/
4. Generates cover image with Gemini → saves alongside content

Output

blogs/
└── prompt-engineering/
    ├── post.md       # Blog content
    └── hero.png      # Generated cover image

linkedin/
└── ai-agents/
    ├── post.md       # Post content
    └── image.png     # Generated image

research/
└── prompt-engineering.md   # Research notes

Customizing

Change the voice: Edit AGENTS.md to modify brand tone and style.

Add a content type: Create skills/<name>/SKILL.md with YAML frontmatter:

---
name: newsletter
description: Use this skill when writing email newsletters
---
# Newsletter Skill
...

Add a subagent: Add to subagents.yaml:

editor:
  description: Review and improve drafted content
  model: anthropic:claude-haiku-4-5-20251001
  system_prompt: |
    You are an editor. Review the content and suggest improvements...
  tools: []

Add a tool: Define it in content_writer.py with the @tool decorator and add to tools=[].

Security Note

This agent has filesystem access and can read, write, and delete files on your machine. Review generated content before publishing and avoid running in directories with sensitive data.

Requirements

• Python 3.11+
• ANTHROPIC_API_KEY - For the main agent
• GOOGLE_API_KEY - For image generation (uses Gemini's Imagen / "nano banana" via gemini-2.5-flash-image)
• TAVILY_API_KEY - For web search (optional, research still works without it)