Claude Skill Codebook Quick Tutorial

Anthropic published the Claude Skill Codebook on GitHub. This isn't dry API docs -- it's a set of "actionable skill workflows" that turn Claude from "can talk about it" into "can actually do it": generating files, running code, building reports.

1. What Exactly Is a Skill?

Think of a Skill as "Claude's micro-toolkit":

• Instructions: Tells Claude what to do and what to output.
• Code: Lets it actually execute (e.g., generate files).
• Resources: Templates, datasets, brand assets, etc. (optional).

The point isn't "learn more knowledge." It's becoming an executor that can complete entire workflows.

2. Codebook Structure

The Codebook has three notebooks:

• Skills Introduction: Generate Excel or PDF from scratch.
• Financial Applications: Data analysis, dashboards, report pipelines.
• Custom Skills: Build your own workflows from zero.

After cloning, the rough structure:

skills/
├── notebooks/
│   ├── 01_skills_introduction.ipynb
│   ├── 02_skills_financial_applications.ipynb
│   └── 03_skills_custom_development.ipynb
├── sample_data/
│   ├── financial_statements.csv
│   ├── portfolio_holdings.json
│   ├── budget_template.csv
│   └── quarterly_metrics.json

3. Getting Started (Actually Running It)

Prerequisites:

• Python 3.8+
• Anthropic API Key
• Jupyter Notebook / JupyterLab

Setup:

git clone https://github.com/anthropics/claude-cookbooks.git
cd claude-cookbooks/skills
python -m venv venv
source venv/bin/activate  # Windows: venv\Scripts\activate
pip install -r requirements.txt
cp .env.example .env
# add your ANTHROPIC_API_KEY to .env
jupyter notebook

Open 01_skills_introduction.ipynb and run the first sample.

4. How Skills Get "Activated"

The key is beta header + container + tool:

from anthropic import Anthropic

client = Anthropic(
    api_key="your-api-key",
    default_headers={
        "anthropic-beta": "code-execution-2025-08-25,files-api-2025-04-14,skills-2025-10-02"
    }
)

Then declare the skill in your request:

response = client.messages.create(
    model="claude-sonnet-4-5-20250929",
    max_tokens=4096,
    container={
        "skills": [
            {"type": "anthropic", "skill_id": "xlsx", "version": "latest"}
        ]
    },
    tools=[{"type": "code_execution_20250825", "name": "code_execution"}],
    messages=[{"role": "user", "content": "Create an Excel budget file"}]
)

5. Example: One Prompt to Generate Excel

from anthropic import Anthropic
client = Anthropic(api_key="your-api-key")

response = client.messages.create(
    model="claude-sonnet-4-5-20250929",
    max_tokens=4096,
    container={
        "skills": [
            {"type": "anthropic", "skill_id": "xlsx", "version": "latest"}
        ]
    },
    tools=[{"type": "code_execution_20250825", "name": "code_execution"}],
    messages=[{
        "role": "user",
        "content": "Create an Excel file with a simple monthly budget"
    }]
)
file_id = extract_file_id(response)
file_content = client.beta.files.download(file_id=file_id)
with open("outputs/budget.xlsx", "wb") as f:
    f.write(file_content.read())

Claude returns the file directly. No Pandas or OpenPyXL needed on your end.

6. Custom Skills (The Real Killer Feature)

Minimal structure:

my_skill/
├── SKILL.md
├── scripts/
│   └── processor.py
└── resources/
    └── template.xlsx

SKILL.md should clearly specify:

• Input format (CSV/JSON/Markdown)
• Output type (Excel/PDF/PPT)
• Core logic (calculations, formatting, template rules)

This lets Claude auto-reuse your workflow on the next run.

7. Practical Tips (Half the Pitfalls)

• Load on demand: Don't enable all Skills at once -- burns tokens fast.
• Batch processing: Run multiple datasets in one request to save API calls.
• File management: Default output goes to outputs/. Watch your naming and overwrites.
• Templates first: For complex layouts, use template + rules for stability.

8. Troubleshooting Quick Reference

9. What Can You Build with Skills?

• Financial reports: CSV → Excel → PDF → PPT
• Operations weekly: Data aggregation + auto charts
• Investment analysis: Portfolio returns, visualization, batch output
• Teaching materials: Markdown → slides + PDF handouts

These workflows are ideal for Skills: structured input + file output.

10. Summary

The Skill Codebook's value isn't "learning one more API." It's building a reproducible automation pipeline. If you consistently need to produce Excel/PPT/PDF output, this skill system cuts your manual steps significantly.

Original link: Claude Skill Codebook - Hubwiz

Source: Toutiao original, curated