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A skill is a SKILL.md file: instructions your agent reads when a task calls for them.
Want to learn by building one agent from start to finish instead? Take the tutorial.

1. Find a skill

Open playwright-cli in the registry. It teaches a model the commands of Microsoft’s browser automation CLI, and its page shows what it changes:
Passed 23 of 23 test cases with the skill, and 7 of 23 without it.
The page also shows the model it ran on, what it costs in tokens, and its safety checks. We use this skill here because the result is easy to see: a model can’t guess this tool’s exact commands. When you’re done, search the registry for one that fits your own agent.

2. Add it where you work

Pick what your agent runs on. For the Python tabs, you need Python 3.10 or later (3.11 for Pydantic AI and Google ADK) and an API key for your model.
Start a new Claude Code session in this folder, because Claude Code finds skills when a session starts. To install skills with a slash command, or to keep them pinned and updatable, see Claude Code.

3. See what it changes

Ask your agent this. In the Python tabs, python main.py already does:
What you should see: the real command.
To compare, take the skill away and ask again. In the Python tabs, run decimalai skills remove playwright-cli. In Claude Code or an editor, delete the file and start a new session. The model now names some other tool, makes a command up, or gives a list of guesses. Then put the skill back, with decimalai skills add playwright-cli or by saving the file again. This skill shows a clear result because it holds facts a model can’t guess. Many skills change an agent less obviously, and a high score doesn’t guarantee they help yours. So test them on your own cases: see Test a change, and Part 5 of the tutorial for a worked example. Here’s what happened in the Python tabs: agent_config() gave your agent a short list of its skills and a load_skill tool. The model read the list, decided this skill applied, and opened it. With no DecimalAI key, the list comes from your project, and nothing is sent to DecimalAI. How skills reach the model has the detail.

Add a key to do more

Your agent works without an account. A free account adds this, on the Python frameworks with agent_config(): Sign up, copy your key from Settings → API keys, and run the same program again:
Run it inside a git repository (git init if you aren’t in one). The first run creates the agent in your workspace, copies your skills onto it, and writes .decimal/link.toml. Outside a repository your skills aren’t copied. Commit that file. From then on, the agent’s skills live on DecimalAI, and decimalai skills add adds a skill to the agent there. Claude Code and editors read files from your project, so a key doesn’t change anything there.

No agent yet?

You don’t need any agent code to start.
  1. Create the agent. Use the dashboard form, start from a skill pack for your kind of agent, or use the CLI:
  2. Generate the code and run it. This looks the agent up by name, and writes an agent.py that reads its prompt and skills from your workspace:
    Prefer another framework? Add --framework with openai-agents, pydantic-ai, adk, anthropic, openai or google-genai, and install what it prints.
  3. Replace the blanks. A pack’s starter prompt has blanks in angle brackets for what only you know, such as <product>. Fill them in on the agent’s Prompt & skills page.

If something goes wrong

  • The model didn’t use the skill. Check the file is where this page says. In Claude Code or an editor, start a new session. You can also ask for it by name: “use the playwright-cli skill”.
  • ModuleNotFoundError. Run the pip install line in the same virtual environment you run main.py from.
  • An older decimalai was installed. On Python 3.10, the Pydantic AI and ADK extras quietly install an older release. pip show decimalai tells you which one you got.
  • No agent named …. The name in decimalai init must match the agent exactly. The error suggests the closest match.
  • No run in the dashboard. Check that DECIMAL_API_KEY is set in the shell that ran your program, then see Troubleshooting.

Next

Your framework

Your own tools, conversations, changing the prompt, and tracing.

Find more skills

Search the registry, read a skill’s results, and start from a pack.

Build a whole agent

The five-part tutorial, from a web page to measured changes in your code.

Write your own skill

Write a skill that triggers at the right times and changes what your agent does.