Fix MCP Inspector 503 error by adding src/requirements.txt for Azure deployment #26
Conversation
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
…per dependency installation Co-authored-by: MiguelElGallo <[email protected]>
Copilot
AI
changed the title
Non-200 status code (503) when connecting to /sse endpoint
Copilot finished work on behalf of
MiguelElGallo
August 20, 2025 10:34
There was a problem hiding this comment.
Pull Request Overview
This PR fixes a 503 error in the MCP Inspector by adding a src/requirements.txt file to ensure proper dependency installation during Azure deployment. The issue occurred because Azure App Service expected the requirements file in the src directory (as specified in azure.yaml with project: src), but it only existed in the root directory, causing deployment failures.
- Added
src/requirements.txtidentical to the root requirements file - Ensures Azure App Service can properly install Python dependencies during deployment
- Resolves 503 errors when connecting to the
/sseendpoint after Azure deployment
MiguelElGallo
approved these changes
Aug 20, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.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.
The MCP Inspector was returning a 503 status code when connecting to the
/sseendpoint after Azure deployment, preventing successful connections to the FastMCP server.Root Cause
Azure App Service expects the
requirements.txtfile to be located in the project directory specified inazure.yaml. Since the configuration setsproject: src, Azure looks for dependencies insrc/requirements.txt, but the file only existed in the root directory. This caused dependency installation to fail during deployment, resulting in application startup failures and 503 errors.The Azure logs showed:
Solution
Added
src/requirements.txt(identical to the rootrequirements.txt) to ensure Azure App Service can properly install Python dependencies during deployment. This allows the FastMCP server to start successfully and the/sseendpoint to be accessible without returning 503 errors.Testing
src/requirements.txtpresentAfter this fix, the MCP Inspector should successfully connect to
https://yourapp.azurewebsites.net/ssewithout encountering 503 errors.Fixes #25.
💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.