# Context Engine

> A multi-tenant context engine: durable memory over an organisation's notes,
> records, files and conversations, searchable by an agent over MCP. Each
> engine is one tenant, with its own database, vector index and credential.

This file is for an LLM or an agent evaluating whether to use Context Engine.
Every link below is served without a credential.

## Start here

- [MCP endpoint](https://app.contextengine.com/mcp): the tool surface, and the whole product. Needs
  a token — either an engine's API key as a bearer credential, or an OAuth 2.1
  access token. It answers 401 without one, and the 401 names the document
  below.
- [Protected resource metadata](https://app.contextengine.com/.well-known/oauth-protected-resource):
  RFC 9728, which is what an MCP client reads after that 401.
- [Authorization server metadata](https://app.contextengine.com/.well-known/oauth-authorization-server):
  RFC 8414. It carries the authorization, token and registration endpoints, so a
  client that has never been heard of here can register itself and obtain a
  token without any of them being written down twice.

- [Tool surface as OpenAPI](https://app.contextengine.com/openapi.json): every tool as
  `POST /tool/<name>`, with its JSON Schema, the scope it needs and the envelope it
  answers in. Generated from the tool registry itself, so it cannot drift from what
  the endpoints do. This is the copy to generate a typed client from; the
  descriptions over `/mcp` are prompts, written for a model rather than for you.

- [Account endpoint](https://app.contextengine.com/account/mcp): a SECOND surface, for the person
  who holds engines rather than for one engine. It lists the engines an account
  belongs to, creates new ones, renames them, stops and starts them, invites and
  removes people, mints and revokes narrow per-integration keys, links one engine to
  another as a read-only source, and reads the bill. It reaches the records inside
  none of them itself. Its scope is `account:manage`,
  deliberately absent from the metadata above: read the 401 from this path, whose
  challenge names its own resource document.
- [The same, as plain HTTP](https://app.contextengine.com/account/mcp/create_engine): one path per
  capability under that endpoint — `POST`, a JSON body, `{data}` back. This is the
  one to build a backend against: you get nothing from an MCP session that a POST
  does not give you when both ends are yours. Every capability and its schema is in
  the OpenAPI document above, under the `account` tag.

## Signing up

You can create an engine in one call, and you do not need an account to do it.
What you cannot do is own one: an engine starts belonging to nobody, and the
person you are acting for becomes its owner by opening a link you hand them.

```
POST https://app.contextengine.com/signup/agent
content-type: application/json

{"email": "the-person@example.com", "name": "Their engine"}
```

The reply carries an API key shown once, the MCP endpoint, and a `claim_url`.
Give the claim_url to that person. Until they open it the engine is on a starter
ceiling, and **it is deleted if nobody claims it** — say so when you report back,
or you will leave somebody a link they do not know they need.

A **202** means the engine and key are live but its search index is still
building. Do not call this route again — that makes a second engine. Poll
`status_url` instead, sending the same key, until `status` is `"ready"`:

```http
GET https://app.contextengine.com/signup/agent/status
authorization: Bearer <the api_key you were given>
```

- [Sign in or create an account](https://app.contextengine.com/login): the way a person does it,
  with no engine created until an address is proved. Never rate limited by the
  agent path above.
- [An account belongs to a person](https://app.contextengine.com/help/account.md): an API key names
  an engine and never a person, so a key you are given carries the reach of the
  engine it belongs to and nothing else.
- [Terms of service](https://app.contextengine.com/terms.md) and [privacy policy](https://app.contextengine.com/privacy.md):
  what the person you are acting for agrees to by claiming an engine, as text.
  Point them at the pages rather than paraphrasing either.

## Free tier

Every engine starts free. The ceilings are enforced rather than advertised — an
answer is refused once either the message count or the spend is reached, and the
calendar month resets both.

- a monthly usage allowance: about 160 answers on the standard model, shared across every engine the account owns
- 2 engines on the account
- 2 connected MCP servers per engine
- up to 32 tool steps in one answer
- voice, added documents and web search count against the same allowance at cost

Paid plans, and what an engine has actually spent, are at
[Plans, limits and what an engine spends](https://app.contextengine.com/help/billing.md).

## Manual

Every topic below is served as Markdown at the link, and as a page for a person
at the same path without `.md`. [The index](https://app.contextengine.com/help/index.json) is the
same set as JSON, with keywords, for choosing one. Content version 1c28cdd344e8.

- [What an engine is](https://app.contextengine.com/help/engine.md): A memory with its own purpose. Your AI tools read the purpose to decide what to keep there.
- [What to ask it](https://app.contextengine.com/help/what-to-ask.md): It answers from what this engine holds. Start with what it already learned, then tell it what your site does not say.
- [Asking a question in the console](https://app.contextengine.com/help/chat.md): Ask, in the console, answers from what this engine holds and names the memories it used.
- [Who can read a conversation](https://app.contextengine.com/help/visibility.md): Private (only you) and team conversations, what private does not cover, and how a new one is set.
- [Finding an earlier conversation](https://app.contextengine.com/help/conversations.md): The Conversations page lists them all, newest first; Ask in the sidebar starts a new one.
- [Finding anything, from anywhere](https://app.contextengine.com/help/searching.md): The bar at the foot of every page finds memories, conversations and pages as you type — ⌘K or Ctrl-K jumps to it.
- [Getting a conversation out](https://app.contextengine.com/help/export-transcript.md): Export a whole conversation as Markdown — copy it, or download the file — to send to somebody looking into a problem.
- [What the engine holds, and how to point at one thing](https://app.contextengine.com/help/records.md): Memories, their types, refs like note::retention-policy, and where to browse them.
- [Attaching and storing files](https://app.contextengine.com/help/files.md): Attach to a message, or bring a whole folder into Files — and what the agent can read of each file.
- [Who can sign in to this engine](https://app.contextengine.com/help/users.md): Owner, admin, member and viewer — what each may do, how to change it, and whose AI tools reach the engine.
- [Who you are in an engine](https://app.contextengine.com/help/profile.md): You are a person in each engine automatically once your account has a name; "what have I been in?" works from day one.
- [Adding somebody to this engine](https://app.contextengine.com/help/invitations.md): People in the sidebar, then Invite people. Asking here does not invite. Only an owner or admin can.
- [Signing in](https://app.contextengine.com/help/signing-in.md): No passwords — a mailed link and code, or Google or GitHub, plus an optional second step.
- [Two-step sign-in](https://app.contextengine.com/help/two-step.md): An authenticator app's code on top of the emailed one. Optional; set up under Account › Sign-in and security.
- [Single sign-on and this engine's security](https://app.contextengine.com/help/single-sign-on.md): Require your company's identity provider for an engine, and where support access is approved and logged.
- [Your account: how you appear and how we reach you](https://app.contextengine.com/help/account.md): Your name, how you sign in, how we reach you, your time zone, and who each engine knows you as.
- [Letting an assistant manage your account](https://app.contextengine.com/help/account-keys.md): On Max, a key or a connected app can list and create engines, invite people, read your bill and make engine keys.
- [Connecting an AI tool](https://app.contextengine.com/help/connections-inbound.md): AI tools — connect Claude, ChatGPT, Cursor or a script, choose its engines, and change or disconnect it later.
- [The API key](https://app.contextengine.com/help/api-key.md): One key per engine, under About on Home. Shown once when it is issued; rotating is how you get one you can use.
- [Plans, usage and what an engine spends](https://app.contextengine.com/help/billing.md): One usage allowance a month, shared by your engines; plans differ in how much, and in a few limits.
- [More than one engine](https://app.contextengine.com/help/engines.md): Switching between engines, creating another, stopping one for a while, and deleting one you own.
- [Taking your engine out, and putting one back](https://app.contextengine.com/help/export-engine.md): Download what an engine holds as a ZIP of Markdown and JSON, and load one back into an empty engine. Owners only.
- [What asking in the console cannot do](https://app.contextengine.com/help/limits.md): Ask sends nothing on its own, keeps nothing after a turn it was not told to keep, and reads only what is public.