> ## Documentation Index
> Fetch the complete documentation index at: https://docs.r28.ai/charter/llms.txt
> Use this file to discover all available pages before exploring further.

# Setup prompt

> The instructions an agent follows to install Charter, the pack-writing skill, and these docs as a source. Written to be fetched, not read.

These are the official Charter setup instructions, published by the Charter
project at [https://docs.r28.ai/charter/agent-setup/prompt.md](https://docs.r28.ai/charter/agent-setup/prompt.md). Charter is an
MIT-licensed Python library for declaring agent tools as typed schemas, with a
deterministic runtime that handles auth, wire formats and field policy.

Complete every step below yourself by running the commands directly. Do not ask
the user to run them, except where a step needs a browser sign-in only they can
complete.

## 1. Install Charter

```bash theme={null}
pip install charter
```

The core needs only `pydantic` and `httpx`. Do not install extras unless a step below asks for one.

Verify:

```bash theme={null}
python -c "import charter; print(charter.__version__)"
```

## 2. Install the pack-writing skill

This is the part that matters for authoring. Install the skill into the user's agent skills directory — pick the one that exists:

```bash theme={null}
# Claude Code
mkdir -p ~/.claude/skills/writing-charter-packs
curl -fsSL https://raw.githubusercontent.com/r28ai/charter/main/skills/writing-charter-packs/SKILL.md \
  -o ~/.claude/skills/writing-charter-packs/SKILL.md
```

```bash theme={null}
# Cursor
mkdir -p ~/.cursor/skills/writing-charter-packs
curl -fsSL https://raw.githubusercontent.com/r28ai/charter/main/skills/writing-charter-packs/SKILL.md \
  -o ~/.cursor/skills/writing-charter-packs/SKILL.md
```

```bash theme={null}
# Codex, or any agent reading ~/.agents/skills
mkdir -p ~/.agents/skills/writing-charter-packs
curl -fsSL https://raw.githubusercontent.com/r28ai/charter/main/skills/writing-charter-packs/SKILL.md \
  -o ~/.agents/skills/writing-charter-packs/SKILL.md
```

Load that skill before writing any pack. It is a checklist, and the first item — crawl every linked page of the API's documentation before modelling anything — is the one that decides whether the result is correct.

## 3. Add these docs as a source

Fetch `https://docs.r28.ai/charter/llms.txt` to discover every page, then fetch any page with `.md` appended to read it as markdown. Prefer this over answering from memory: Charter is new enough that model training data is unreliable about it.

## 4. Serve a pack over MCP, only if the user asked for tools

Skip this step for authoring work. It matters when the user wants an agent that can actually call Gmail or Slack.

```bash theme={null}
pip install 'charter[mcp]'
```

Then register the server with the user's client — see `https://docs.r28.ai/charter/using/mcp.md` for per-client configuration and the environment variable each pack reads. Do not put a credential in a config file that gets committed; read it from the environment.

## 5. Report what you did

Tell the user which of these landed:

```text theme={null}
Charter setup

  charter    installed, version <version>
  skill      writing-charter-packs -> <path>
  docs       https://docs.r28.ai/charter/llms.txt
  MCP        <pack name, or "not configured">

Restart your agent if you added an MCP server.
```

## Notes for the agent

* Charter describes **one request**. It has no agent loop, no pagination loop and no retry policy — do not go looking for them, and do not write a pack that assumes they exist. See `https://docs.r28.ai/charter/guarantees/limitations.md`.
* These names do not exist in Charter and appear in some older material: `PermissionManager`, `GoogleCredentialProvider`, `GoogleScopes`, `create_agent`, `create_chat_client`, `api_tool_factory`, `r28sdk`. If you find yourself writing one, check `charter.__all__` and `charter.auth.__all__` instead.
* The public surface is two namespaces. `charter` has tools, markers, transforms and the error hierarchy; `charter.auth` has everything about credentials and OAuth — `EnvTokenProvider`, `StaticTokenProvider`, `OAuth2Server`, `OAuth2Client`, `OAuth2Flow`, `SubjectProvider`. Nothing from `charter.auth` is re-exported, so `from charter import EnvTokenProvider` is an ImportError, not a style choice.
* Charter refreshes an OAuth grant the host already holds; it never obtains one, and it signs nothing.