Add MCP server (stdio + HTTP) reusing the skill's Graph client

New mcp-server/ exposes SharePoint Lists as MCP tools (test, list_lists, get_columns, list_items, get_item, create/update/delete_item) via the same graph.mjs core. Supports stdio (Claude Desktop/Code/Cowork) and Streamable HTTP (--http). SP_READONLY gates write tools. Adds project .mcp.json and ignores build artifacts. Verified end-to-end live over stdio and HTTP initialize.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mcp-server/README.md

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+# sharepoint-lists MCP server
+
+An [MCP](https://modelcontextprotocol.io) server exposing Microsoft SharePoint
+Lists as tools, using app-only (client-credentials) Microsoft Graph auth. It
+reuses the same core client as the skill
+(`../.claude/skills/sharepoint-lists/scripts/lib/graph.mjs`) — one source of
+truth for the Graph logic.
+
+## Tools
+
+| Tool | Access | Purpose |
+|---|---|---|
+| `sharepoint_test` | read | Verify credentials; with a site, list its lists |
+| `sharepoint_list_lists` | read | Enumerate lists in a site |
+| `sharepoint_get_columns` | read | Column internal names + types (call before writing) |
+| `sharepoint_list_items` | read | Query items (filter/select/orderby/top/all) |
+| `sharepoint_get_item` | read | Get one item by id |
+| `sharepoint_create_item` | write | Create an item |
+| `sharepoint_update_item` | write | Update an item (partial) |
+| `sharepoint_delete_item` | write | Delete an item (irreversible) |
+
+Set `SP_READONLY=true` to register only the read tools.
+
+## Setup
+
+```bash
+cd mcp-server
+npm install
+cp .env.example .env      # then fill in SP_TENANT_ID / SP_CLIENT_ID / SP_CLIENT_SECRET
+```
+
+Credentials and the optional `SP_SITE_URL` default are documented in
+`../.claude/skills/sharepoint-lists/references/setup.md`.
+
+## Run
+
+**stdio** (Claude Desktop / Claude Code / Cowork — local):
+
+```bash
+npm start            # node index.mjs
+```
+
+**Streamable HTTP** (for a hosted/remote connector):
+
+```bash
+npm run start:http   # node index.mjs --http   → http://localhost:3838/mcp
+```
+
+## Connect it
+
+### Claude Code
+A project `.mcp.json` at the repo root already registers this server. From the
+repo root, Claude Code will offer to start it (approve the prompt). Ensure
+`mcp-server/.env` is filled in first.
+
+### Claude Desktop (stdio)
+Add to `claude_desktop_config.json`:
+
+```json
+{
+  "mcpServers": {
+    "sharepoint-lists": {
+      "command": "node",
+      "args": ["/absolute/path/to/Claude-SharepointLists/mcp-server/index.mjs"]
+    }
+  }
+}
+```
+
+### Claude.ai web (remote connector)
+Run with `--http` and expose it over **HTTPS** with authentication (a reverse
+proxy / tunnel, plus typically OAuth). claude.ai cannot reach `localhost`, and
+custom connectors expect an authenticated HTTPS MCP endpoint — see the repo
+README's "Remote hosting" notes before exposing this publicly.
+
+## Notes
+
+- App-only auth means there is no per-user permission check — every caller of
+  this server acts as the app. Don't expose it unauthenticated.
+- Field formats for writes (person/lookup/choice/date) are documented in
+  `../.claude/skills/sharepoint-lists/references/graph-api.md`.