Serve MCP over streamable HTTP on /mcp (MCP_TRANSPORT=http) - #114
Merged
Conversation
Adds a runStreamableHttp() mode next to stdio and legacy SSE. Stateless by design: every request gets its own Server + StreamableHTTPServerTransport (sessionIdGenerator: undefined) and nothing is remembered between requests — the tool surface is genuinely stateless (servers and caches are module-level), so sessions would buy nothing but bookkeeping: a Map to leak on unclean disconnects and 404s after a restart. Constructing a Server is handler registration only; it opens no sockets. The endpoint parsing (MCP_HOST/MCP_PORT) and the non-loopback warning are factored out of runSse() and shared. /mcp and /mcp/ are both accepted (clients differ; the Python EIC servers' Starlette router redirects rather than 404s), everything else 404s. An unknown MCP_TRANSPORT value used to fall back to stdio silently, which made an HTTP launcher hang until its readiness probe timed out; it now fails loudly.
Mirrors sse.test.ts over StreamableHTTPClientTransport, plus stateless-mode specifics: sequential clients work independently, /nope 404s, /mcp/ (trailing slash) does not.
MCP_TRANSPORT was previously undocumented. Also fixes the stale build/index.js path in QUICKSTART (the artifact is build/src/index.js).
Contributor
There was a problem hiding this comment.
Pull request overview
This PR adds a new stateless Streamable HTTP transport option for the MCP server at /mcp (selected via MCP_TRANSPORT=http), alongside existing stdio (default) and legacy sse. It also updates documentation and bumps the project version to v0.2.0 in preparation for the no-supergateway migration.
Changes:
- Add Streamable HTTP server mode (
/mcp) with loopback-exposure warning and explicit failure on unknownMCP_TRANSPORT. - Add an HTTP smoke test validating tool listing, stateless sequential clients, 404 behavior, and
/mcp/handling. - Update docs/examples and container metadata for the new transport; bump version to
0.2.0.
Reviewed changes
Copilot reviewed 6 out of 7 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| test/http.test.ts | Adds a smoke test for the new Streamable HTTP transport. |
| src/index.ts | Implements Streamable HTTP mode (/mcp), refactors HTTP bind parsing, makes invalid MCP_TRANSPORT fail loudly, bumps in-code version strings. |
| README.md | Documents available transports and provides HTTP client configuration example. |
| QUICKSTART.md | Updates standalone path and adds Streamable HTTP usage snippet. |
| package.json | Bumps package version to 0.2.0. |
| package-lock.json | Keeps lockfile version in sync with 0.2.0. |
| Dockerfile | Exposes port 9102 and documents how to run HTTP mode in Docker. |
💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
wdconinc
reviewed
Sep 3, 2026
wdconinc
reviewed
Sep 3, 2026
Contributor
|
Added two more comments (same issue). Do we need version number? |
Contributor
Author
|
indeed, removed it, kept only the one MCP needs |
wdconinc
enabled auto-merge (squash)
September 4, 2026 12:58
wdconinc
approved these changes
Sep 4, 2026
wdconinc
approved these changes
Sep 4, 2026
Contributor
|
Not sure why this didn't want to auto merge... |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Adds a stateless streamable-HTTP mode (fresh Server + transport per request) next to stdio and legacy SSE;
MCP_HOST/MCP_PORTas before, endpoint127.0.0.1:9102/mcp. UnknownMCP_TRANSPORTnow fails loudly instead of silently using stdio. Tests: 91/91 incl. newhttp.test.ts.Part of the no-supergateway migration (eic-spack#986, containers#357). Tag
v0.2.0after merge.