# NEXUS

> NEXUS is the shared memory of a user's AI agents, exposed as an MCP server, so they stop repeating costly mistakes and contradicting decisions already made. Claude Code, Claude, ChatGPT, Cursor and any MCP client recall decisions, business rules and past mistakes before acting, across sessions, from one knowledge graph all of the user's agents share. Open sign-up; free plan ("Gratuito") with up to 150 new memories and 2 agents per month. Operated by Satoshi Payments, S.A.S. de C.V. (Mexico).

NEXUS es un servidor de memoria persistente para agentes de IA vía MCP. La página está en español en / y en inglés en /en.

## Connect (for AI agents)

- MCP endpoint (Streamable HTTP): https://nexus.eblas.link/mcp
- Authentication is REQUIRED. An unauthenticated request returns 401 with `WWW-Authenticate: Bearer ... resource_metadata="https://nexus.eblas.link/mcp/.well-known/oauth-protected-resource"`.
- Option A — OAuth 2.1: authorization code + PKCE (S256), dynamic client registration (RFC 7591), public clients (token_endpoint_auth_method "none"). Scopes: `memoria grafo cognicion trabajo`. Discovery: https://nexus.eblas.link/.well-known/oauth-protected-resource and https://nexus.eblas.link/.well-known/oauth-authorization-server
- Option B — agent credential: a token starting with `nxa_`, issued by the account owner in the web console (Credentials), sent as `Authorization: Bearer nxa_...`.
- Claude Code: `claude mcp add --transport http nexus-agi https://nexus.eblas.link/mcp --header "Authorization: Bearer nxa_..."`
- JSON config (Claude Desktop, Cursor `.cursor/mcp.json`, generic): `{"mcpServers": {"nexus-agi": {"type": "http", "url": "https://nexus.eblas.link/mcp", "headers": {"Authorization": "Bearer nxa_..."}}}}`
- A NEXUS account is required; without one the OAuth flow cannot complete. Sign-up is open and free at https://nexus.eblas.link/en/signup.

## First steps after connecting

1. Optional, for agents on the user's machine (Claude Code, Cursor): `get_setup_kit()` (Cursor: `client="cursor"`) returns three hooks (SessionStart, UserPromptSubmit, Stop) and an idempotent installer. Installing is the user's decision. Without the hooks NEXUS only has what the agent stores through its tools.
2. Chat clients (ChatGPT, Claude web/desktop/mobile) have no hooks. What makes them recall is a short block the user pastes into the client's instructions: call `retrieve_memories` every turn with the user's message and `time_range="all_time"`, decide any `duda_de_fusion` with `decide_merge_proposal` before answering, and store what was learned with `process_observation`. Text and steps: https://nexus.eblas.link/documentacion (section 4).
3. Call `whoami()` to confirm which account and credential you are using.
4. Store with `process_observation(content, entity_hints, relations)`; recall with `cognitive_query(topic)` or `retrieve_memories(query)`; call `run_cognitive_cycle()` after bulk writes.
5. Goals: `create_goal` → `activate_goal` → `update_goal` → `close_goal`.

## REST API

- Base: https://nexus.eblas.link/api/v1 (memory under https://nexus.eblas.link/memory), same `Authorization: Bearer` credential.
- Every REST client MUST send its own User-Agent header (e.g. `nexus-hooks/1.0`). Cloudflare rejects Python-urllib's default User-Agent with 403 (error 1010).
- Health check: `GET https://nexus.eblas.link/api/v1/metacognition/health` → 200 with a valid credential.

## No account yet? Create one

Sign-up is open, no invite needed: https://nexus.eblas.link/en/signup. The human enters their email and an account name and confirms with a 6-digit code sent to that email (or continues with Google, when offered). The free plan ("Gratuito") includes up to 150 new memories and 2 active agents per month, without URL or document ingestion; paid plans are optional. Sign-up is a human step confirmed by email, so there is no sign-up flow for agents: send your human that link.

## Pages

- [Home (Spanish)](https://nexus.eblas.link/): benefits, how it works, FAQ
- [Create an account](https://nexus.eblas.link/en/signup): open sign-up, free plan
- [Home (English)](https://nexus.eblas.link/en)
- [Full agent reference](https://nexus.eblas.link/llms-full.txt): every MCP tool, grouped
- [Términos y Condiciones](https://nexus.eblas.link/terminos) · [Terms (EN)](https://nexus.eblas.link/en/terms)
- [Aviso de privacidad](https://nexus.eblas.link/privacidad) · [Privacy Notice (EN)](https://nexus.eblas.link/en/privacy)
- [Políticas de uso](https://nexus.eblas.link/politicas-de-uso) · [Usage Policies (EN)](https://nexus.eblas.link/en/usage-policies)