Nexusm Server

Nexusm MCP Server — generic MCP server exposing Nexusm core capabilities (memory, conversation, knowledge, feedback, context) to MCP clients via @modelcontextprotocol/sdk stdio + Streamable HTTP transports.

Published to npm as @nexusm/mcp-server.

Tracked in Nexusm main repo: packages/nexusm-mcp-server (US-037 v7.0).

Configuration

Set via environment (e.g. the env block of your client's .mcp.json):

Env var	Required	Purpose
NEXUS_API_URL	yes	Base URL of the Nexus REST API. The server auto-appends /v1 if absent, so a bare origin (http://localhost:8787) or a local proxy URL works — you don't need to add the suffix manually. Canonical form: https://your-nexus-host/v1.
NEXUS_API_TOKEN	yes	Nexus API key (the product auth contract)
NEXUS_TENANT_ID	yes	Tenant id for the compound-id isolation
NEXUS_DEFAULT_USER_ID	no	Single-user pin. When set to a non-empty value, the server uses it as user_id for every tool call, overriding whatever user_id the LLM supplies. Leave unset for multi-user deployments where each tool call provides its own user_id. Recommended for personal / dogfood setups where the LLM picks inconsistent IDs across sessions. ⚠️ Do NOT set this on a shared / multi-user server — every user's memories and context would be written and retrieved under this single id, silently collapsing all users into one (cross-user memory bleed).
NEXUS_METRICS_PORT	no	Opt-in Prometheus /metrics port. Off by default in stdio mode — the scrape endpoint is a server-side concern, and a local stdio client (Claude Code / Cursor / Windsurf) has no scraper. Set this only when you actually scrape metrics. (NEXUS_MCP_TRANSPORT=http also enables it.)

The Nexus API auth contract is NEXUS_API_TOKEN. Any deployment-edge access control in front of the API (e.g. a reverse proxy / gateway / Cloudflare Access) is not this client's concern — handle it transparently at the network/transport layer (point NEXUS_API_URL at a local proxy) so the client stays deployment-agnostic. When pointing at a local proxy, set NEXUS_API_URL to the proxy origin (e.g. http://localhost:8787); the server will append /v1 automatically and log a one-line diagnostic to stderr confirming the normalization.

Status

Wave 2 done (2026-05-22): 4 tools fully wired to @nexusm/sdk (context_retrieve / memory_search / memory_create / memory_feedback) + full §M-3 HTTP→MCP error mapping (mapHttpStatusToMcpError + 2 new error codes Unauthorized/RateLimited) + Prometheus metrics with cardinality guard + cross-substory + E2E + schema_sync integration tests. Wave 3 (nexus-claude-plugin Anthropic marketplace) pending — see proposal.

Known Wave 2 limitations: (1) CI red until Gate-1 — @nexusm/[email protected] npm publish pending (user action; SDK rename merged at 1fbdd69 in nexus-sdk-js main); (2) integration tests env-gated (require NEXUS_TEST_API_URL/TOKEN/TENANT_ID Forgejo secrets, currently dormant); (3) Python backend mcp.py metrics defined but emit-site wiring deferred to Wave 3 (FU-MCP-BACKEND-EMIT-WIRING); (4) HTTP transport per-request server.connect() is scaffold-only — Wave 3 entry condition (FU-MCP-HTTP-SESSION) before plugin TASK-019 E2E runs.