fix: give the MCP service its own railway.json (it was building the backend Dockerfile)

[DevanshuNEU]

Problem

The MCP service (mcp.opencodeintel.com) has been failing every deploy since #296 (~2 months) and is frozen on that stale image. Deploy logs show:

Error loading ASGI app. Could not import module "main".

repeated until all 11 healthcheck attempts fail with "service unavailable".

Root cause

There is a single repo-root railway.json that is backend-specific:

"build": { "dockerfilePath": "backend/Dockerfile", "buildContext": "backend" },
"deploy": { "healthcheckPath": "/health", ... }

Railway feeds this config to both services by default. The backend service reads it correctly. The MCP service inherits it and builds backend/Dockerfile, whose CMD is uvicorn main:app -- but mcp-server/ has no main.py, only server.py. So uvicorn crashes at boot on every MCP deploy.

The MCP code itself is fine: mcp-server/server.py reads $PORT via config.py and serves a public /health route. The only problem is which Dockerfile Railway builds for that service.

Fix

Stop the two services from sharing one backend-shaped config. Add a dedicated mcp-server/railway.json that builds mcp-server/Dockerfile with its own /health healthcheck. The backend service keeps reading the repo-root railway.json unchanged (it was just restored in #319; not touching it).

Deliberately not doing what Railway's auto-diagnosis suggested (stripping dockerfilePath from the root railway.json) -- that would remove the backend's build + healthcheck config and risk re-breaking the service #319 just fixed.

Activation (required, manual)

This file is inert until the MCP service is pointed at it. In the Railway dashboard:
MCP service (marvelous-endurance) -> Settings -> Config-as-code file path -> mcp-server/railway.json, then redeploy. The backend service is left on the repo-root railway.json.

Testing

• Confirmed mcp-server/Dockerfile runs python server.py (not uvicorn main:app) and its healthcheck already uses ${PORT:-8080}.
• Confirmed server.py binds $PORT and registers a public /health route.
• Real validation: the next MCP deploy after the config-path change should pass healthcheck on $PORT.

Summary by CodeRabbit

• Chores
  • Configured MCP server deployment infrastructure with automated health monitoring and failure recovery mechanisms.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 2650628f-bb15-4365-bc80-be2e5298aa95

📥 Commits

Reviewing files that changed from the base of the PR and between 435c4e3 and 61e4ad3.

📒 Files selected for processing (1)

• mcp-server/railway.json

📝 Walkthrough

Walkthrough

This PR introduces a Railway deployment configuration file for the MCP server, specifying Docker build context, healthcheck endpoint targeting /health with a 300-second timeout, and deployment restart policies with a maximum of 10 retries on failure.

Changes

Railway MCP Server Deployment

Layer / File(s)	Summary
Railway deployment configuration mcp-server/railway.json	Railway configuration JSON specifies Docker-based build context (mcp-server), healthcheck endpoint (/health, 300s timeout), and restart policy (ON_FAILURE, max 10 retries).

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~5 minutes

Possibly related PRs

• OpenCodeIntel/opencodeintel#310: Modifies mcp-server/railway.json's deploy settings by removing startCommand to fix healthcheck/start behavior.
• OpenCodeIntel/opencodeintel#284: Adds Dockerfile and health endpoint changes for the MCP server that work alongside this Railway configuration's healthcheck targeting /health.

Poem

🐰 A config so small, yet mighty and true,
Railway awaits what the MCP will do,
Health checks and restarts in JSON so neat,
One file, complete, makes deployment sweet! 🚂✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main fix: providing a dedicated railway.json configuration file for the MCP service instead of it incorrectly using the backend Dockerfile.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

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• Create PR with unit tests

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Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@mcp-server/railway.json`:
- Around line 4-6: The railway.json currently uses an unsupported "buildContext"
key; remove that key and rely on supported fields ("builder" and
"dockerfilePath") instead, then ensure the Docker build uses the correct source
by either moving the Dockerfile/Docker build context so dockerfilePath points at
the desired root (e.g., place Dockerfile at repository root or adjust
dockerfilePath to the correct location) and/or update mcp-server/Dockerfile
COPY/ADD paths to be source-root-agnostic; check and update "builder" and
"dockerfilePath" in railway.json and the mcp-server/Dockerfile COPY/ADD lines to
guarantee the intended files are available during build.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 40d4e015-aed5-4402-9791-4839befaa7b1

📥 Commits

Reviewing files that changed from the base of the PR and between 8afb4e5 and 435c4e3.

📒 Files selected for processing (1)

• mcp-server/railway.json

[DevanshuNEU]

Addressed the buildContext review finding. Verified against Railway's config schema: supported build keys are builder, watchPatterns, buildCommand, dockerfilePath, railpackVersion -- buildContext is not one and was silently ignored. Removed it.

Railway sets the Docker build context via the Root Directory service setting ("only pulls down files from that directory"), not a config key. So the build context comes from setting Root Directory = mcp-server; with that, the context is already mcp-server/, the Dockerfile is auto-detected at the context root, and the Dockerfile's COPY . . / COPY requirements.txt . resolve correctly with no edits. A repo-root-relative dockerfilePath: mcp-server/Dockerfile would be wrong inside that restricted context, so it's dropped too. Config now keeps only supported keys + the deploy healthcheck block.

Corrected activation (dashboard, after merge), both required:

1. MCP service -> Settings -> Root Directory = mcp-server (sets build context; this is what stops it building backend/Dockerfile).
2. MCP service -> Settings -> Railway Config File = mcp-server/railway.json (repo-root-absolute path; it does not follow Root Directory).
   Then redeploy. The backend service is untouched (still on the repo-root railway.json).

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
opencodeintel	Ignored	Preview	Jun 12, 2026 12:36am