This repository provides ready-to-run MCP services and reusable packages that connect LLM/MCP clients to external systems. It currently includes GitHub and Microsoft Outlook services, plus a small auth helper.

• Motivation
• What’s Included
• Quick Start
• Configuration
• Development
• Contributing
• License
• Authors

The goal of this project is to make it straightforward to expose common developer and productivity systems to MCP-compatible clients. Each service:

• Implements an MCP server with a compact HTTP endpoint.
• Handles OAuth/device login flows with clear, user-friendly prompts.
• Exposes practical tools and operations tailored to the target system.

• GitHub MCP

  • Binary: github/cmd/github-mcp
  • Service package: github/service
  • MCP tools: github/mcp

• Outlook MCP

  • Binary: outlook/cmd/outlook-mcp
  • Service + tools: outlook/mcp, outlook/service, outlook/graph

• Shared

  • Auth helper: auth (derives caller namespace from JWT in context)

Note: Some local or experimental modules may exist in the repository but are intentionally not part of this distribution overview.

Prerequisites:

• Go 1.25+

Runs an MCP server with endpoints for GitHub operations and an auth flow using GitHub Device Code. Client ID is optional; when omitted, you can still POST tokens via HTTP.

Run:

go run ./github/cmd/github-mcp \
  -a :7789 \
  -o "ipd_xxx.enc|blowfish://default" -i
  

Endpoints (selected):

• GET / – root redirect/info
• POST /mcp/call – MCP RPC endpoint
• POST /github/auth/start – start Device Code flow (returns verify URL + code)
• GET /github/auth/oob – out‑of‑band UI to paste a token, basic credentials, or start device flow; accepts alias, optional domain, optional url=domain/owner/repo, and uuid to bind to namespace
• POST /github/auth/token – ingest a personal access token or basic credentials; accepts alias, domain, optional owner, repo, and uuid (recommended) to bind to namespace
• GET /github/auth/check – check whether a token exists; accepts alias, domain, optional owner, repo, and uuid
• GET /github/auth/verify – verify access to a repo default branch; accepts alias, domain, url=domain/owner/repo, and uuid
• GET /github/auth/pending – list pending device codes for the current namespace
• POST /github/auth/pending/clear – clear pending device codes for the current namespace

Common tools registered by the server include listing repositories, issues/PRs, creating issues/PRs, commenting, searching issues, checking out repos, listing repo paths, and downloading files.

Runs an MCP server integrated with Microsoft Graph using Device Code flow. You can pass Azure client details directly or load them via a scy EncodedResource.

Run with flags:

go run ./outlook/cmd/outlook-mcp \
  --a :7788 \
  --azure-ref "azure-cred|blowfish://default"
   -o "ipd_xxx.enc|blowfish://default" -i

Or environment variables:

export OUTLOOK_CLIENT_ID=00000000-0000-0000-0000-000000000000
# Optional: OUTLOOK_TENANT_ID defaults to "organizations" if not set.
# export OUTLOOK_TENANT_ID=organizations
export OUTLOOK_AZURE_REF='gcp://secretmanager/projects/myproj/secrets/azure-cred|blowfish://default'
go run ./outlook/cmd/outlook-mcp -addr :7788 --secretsBase mem://localhost/mcp-outlook

For more on Outlook configuration, see outlook/mcp/README.md.

Both servers derive a public callback base URL from -addr automatically (e.g., http://localhost:7789). You can override this with --public-base-url to use a non-localhost host (useful behind proxies or in-cluster services), for example --public-base-url http://mcp-toolbox-github.agently.svc.cluster.local:7789. Storage directories default to a subfolder in the user config directory.

• GitHub

  • Flags: -addr, --public-base-url, -client-id, -storage, -o/--oauth2config, -i/--use-id-token, --secretsBase
  • Env (optional):
    • GITHUB_MCP_WAIT_SECS: max wait for credentials (default 300s)
    • GITHUB_MCP_ELICIT_COOLDOWN_SECS: cooldown between repeated credential prompts (default 60s)

• Outlook

  • Flags: -addr, --public-base-url, -client-id, -tenant-id, -azure-ref, -o/--oauth2config, -i/--use-id-token, --secretsBase
  • Env: OUTLOOK_CLIENT_ID, OUTLOOK_TENANT_ID, OUTLOOK_AZURE_REF
  • -azure-ref/OUTLOOK_AZURE_REF uses scy EncodedResource to load cred.Azure secrets (supports file/GCP/AWS backends with KMS like blowfish://default).

MCP requests and stored credentials are isolated by a “namespace” derived from the caller’s identity:

• With server auth enabled (-o/--oauth2config), the authorizer places a token in the request context. We extract email or sub (subject) from that token to form the namespace. If neither can be extracted, we fall back to a stable token hash namespace tkn-<md5> to prevent cross-user leakage.
• Without server auth, if the caller supplies Authorization: Bearer <jwt>, we still derive namespace from claims or fall back to tkn-<md5>; otherwise, the namespace defaults to default.

Per-namespace separation in this repo:

• GitHub: tokens, wait/wakeup keys, and repo tree caches are keyed by namespace. Elicitation is deduped per session and per namespace (no cross‑namespace suppression). Out‑of‑band flows include a uuid that binds the UI to the original namespace so token saves land in the correct scope.
• Outlook: authentication records (disk/AFS), azidentity caches, and in‑memory clients/creds are keyed by namespace. Concurrent acquisitions are serialized per ns+alias to avoid duplicate prompts.

Important for remote deployments:

• To guarantee isolation across concurrently connected users, run with both -o and -i (ID tokens) and ensure the client completes the BFF/auth flow. Otherwise, auth tokens or connections obtained under a weaker namespace (e.g., default) could be visible to other users via fallback behavior.
• If you intentionally share credentials (e.g., a team-wide token), you may omit -o/-i and rely on the default namespace, but be aware this is shared across users.

HTTP auth endpoints and BFF:

• JSON‑RPC (/mcp) calls are mediated by the authorizer when -o is set.
• Custom HTTP auth endpoints (/github/auth/*, /outlook/auth/*) can be wrapped by the authorizer, or you can pass Authorization: Bearer <id_token> directly. GitHub’s OOB UI also uses a uuid to bind subsequent HTTP requests to the original namespace.

GitHub checkout destination:

• When destDir is not provided, checkouts are written under a namespaced path to avoid collisions:
  • Parent: storageDir if set, else OS temp dir
  • Final path: <parent>/<namespace>__<alias>/gh_<owner>_<repo>
  • Example: /tmp/[email protected]__work/gh_viant_mdp

Both GitHub and Outlook can persist credentials to a storage backend via --secretsBase (AFS/scy URL):

• mem:// – in-memory storage for the life of the process (great for local dev/tests)
  • Example: --secretsBase mem://localhost/mcp-github
  • Example: --secretsBase mem://localhost/mcp-outlook
• file:// – local filesystem paths
  • Example: --secretsBase file://~/.mcp/github
  • Example: --secretsBase file://~/.mcp/outlook
• Cloud/KMS – use scy EncodedResource patterns to load secrets and pair with AFS URLs for storage
  • Example: -o gcp://secretmanager/projects/<proj>/secrets/idp|blowfish://default

Layout is namespaced to enforce user isolation:

• GitHub tokens: <secretsBase>/github/<ns>/<alias>/<domain>[/<owner>/<repo>]/token
• Outlook auth record: <secretsBase>/outlook/<ns>/<alias>/auth_record.json

BFF notes

• The servers use the default Backend‑For‑Frontend (BFF) header (X-Authorization-Exchange) and cookie (BFF-Auth-Session) just like mcp-sqlkit. No custom redirect URI is required; clients should follow the initial 401 challenge, complete the exchange, and retain the cookie for subsequent /mcp calls.

• Build a server:
  • go build ./github/cmd/github-mcp
  • go build ./outlook/cmd/outlook-mcp
• Run in place using go run as shown in Quick Start.
• The MCP HTTP server is provided by github.com/viant/mcp/server and speaks the github.com/viant/mcp-protocol.

Contributions are welcome! Please open issues or pull requests with clear reproduction details and proposed changes.

The source code is available under the Apache License 2.0. See LICENSE for details.

• Adrian Witas
• Viant Contributors