# 9th Protocol

> Documentation for 9p, an agentic coding CLI that runs in your terminal and lets you choose the model. Covers installation, authentication, the Auto model router, permissions, memory and vaults, skills, MCP servers, context compaction, and billing. Mintlify serves this description plus a page index at /llms.txt and the full text at /llms-full.txt.

## Docs

- [Introduction](https://docs.9thprotocol.com/introduction.md): 9th Protocol is an agentic coding CLI that runs in your terminal, on whichever model fits the task.
- [Installation](https://docs.9thprotocol.com/installation.md): Install the 9p CLI from npm and sign in.
- [Quickstart](https://docs.9thprotocol.com/quickstart.md): From install to a real code change in about a minute.
- [Authentication](https://docs.9thprotocol.com/authentication.md): Sign in with the device flow, use your own OpenRouter key, or authenticate with environment variables.
- [CLI reference](https://docs.9thprotocol.com/cli.md): Every 9p command, slash command, and configuration file.
- [Permissions](https://docs.9thprotocol.com/permissions.md): What 9p can do without asking, and how to change it.
- [Models & Auto routing](https://docs.9thprotocol.com/models.md): How 9p picks a model for each turn, and how to override it.
- [Context & compaction](https://docs.9thprotocol.com/context.md): How 9p keeps a long session inside the model's context window.
- [Sub-agents](https://docs.9thprotocol.com/sub-agents.md): Parallel agents with their own context for search and unattended work.
- [Memory](https://docs.9thprotocol.com/memory.md): Standing instructions 9p reads at the start of every session.
- [Vault](https://docs.9thprotocol.com/vault.md): A folder of linked markdown that 9p navigates instead of re-reading your codebase.
- [Skills](https://docs.9thprotocol.com/skills.md): Package a repeated workflow into a slash command.
- [MCP servers](https://docs.9thprotocol.com/mcp.md): Add any Model Context Protocol server's tools to a session.
- [VS Code](https://docs.9thprotocol.com/vscode.md): Run 9p inside your editor.
- [9p serve](https://docs.9thprotocol.com/serve.md): A local browser session with the same engine as the CLI.
- [Plans](https://docs.9thprotocol.com/plans.md): What each plan includes and which models it unlocks.
- [Credits & usage](https://docs.9thprotocol.com/credits.md): How metering works, why cache hits matter, and where to see your spend.
- [SDK](https://docs.9thprotocol.com/sdk.md): Programmatic access to the 9th Protocol agent.