> ## Documentation Index
> Fetch the complete documentation index at: https://open-index.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Open Index as your agent's context layer

> Expose a brain over MCP so agents can read domain context and keep it current.

`open-index mcp` runs an MCP server (stdio) exposing the brain to any MCP client —
**read and write by default**.

## The tools

* The server publishes dynamic, brain-specific instructions as part of the agent
  prompt so supporting hosts can navigate the domain before the first tool call.

<CardGroup cols={2}>
  <Card title="navigation_guidelines()" icon="compass">
    Refresh the domain guide after the index or schema changes — reports doc\_types,
    fields, and the relationship vocabulary of *your* brain.
  </Card>

  <Card title="search_brain(query, doc_types, limit)" icon="magnifying-glass">
    Retrieve domain context by query, optionally scoped to doc\_types.
  </Card>

  <Card title="get_entity(id)" icon="cube">
    Fetch a single entity by its `<doc_type>:<slug>` id.
  </Card>

  <Card title="put_entity(...) / put_entities([...])" icon="pen">
    Add or update entities — validated, honoring the storage policy. `put_entities`
    writes a whole batch in one call with a shared `provenance` block.
  </Card>

  <Card title="create_doc_type(...)" icon="shapes">
    Define a new concept from the agent side.
  </Card>
</CardGroup>

## Read-only mode

Use `open-index mcp --read-only` (or `open-index serve --read-only`) to opt out when
an agent should retrieve domain context but never maintain it.

```bash theme={null}
open-index mcp --brain ./my-brain                 # read + write (default)
open-index mcp --brain ./my-brain --read-only     # retrieval only
```

## Local context-fetch analytics

CLI and MCP searches, entity fetches, and navigation-guide reads are recorded in the
user's local state directory (`~/.local/state/open-index/`), outside the brain
checkout. The Analytics tab shows fetch counts by client/operation, frequently
fetched queries or entity IDs, latency, failures, zero-result searches, and recent
activity.

<Note>
  This file stays local and is never sent to Open Index's creators.
</Note>

## Claude Code conveniences

`open-index init` includes optional Claude Code conveniences: `.mcp.json`, a
`CLAUDE.md` describing durable editing workflows (not runtime navigation), and an
**`edit-brain` skill**. They are one client integration, not a requirement for
building legal, marketing, support, or other specialized agents on Open Index.

## Portable agent setup skill

`skills/setup-open-index/SKILL.md` follows the portable Agent Skills `SKILL.md`
format used by agent runtimes including OpenClaw, Hermes, and Claude Code. Give or
install this skill in the selected runtime when the agent should set up Open Index
itself. It covers installation, domain-brain initialization, generic MCP wiring,
default read/write verification, the `--read-only` opt-out, and production
guardrails.

## Connecting a client

For the exact config block per client (Claude Code, Claude Desktop, Cursor) and the
remote HTTP path, see [Deployment → Connecting your agent](/deployment#5-connecting-your-agent).