Top-level CopilotClient import crashes entire Function host if github-copilot-sdk fails to install

[paulyuk]

Problem

function_app.py imports CopilotClient and initializes it at module level:

from copilot import CopilotClient, PermissionHandler
client = CopilotClient()

If the github-copilot-sdk package fails to install on Azure Functions Linux (Flex Consumption), this crashes the entire Function host with a 503. No endpoints load — not just the agent endpoint, but all HTTP triggers and all timer triggers become unavailable.

Root Cause

Azure Functions Python v2 loads function_app.py at startup. Any top-level import failure prevents the module from loading, which prevents the Functions runtime from discovering and registering any routes. The host returns Function host is not running (503) for every request.

Impact

• All HTTP endpoints return 503 (not just the agent endpoint)
• All timer triggers stop firing (scheduled jobs silently fail)
• No error is surfaced in the Azure Portal — the app appears deployed but is completely non-functional
• Difficult to diagnose: the deployment succeeds, the function list shows empty, and logs may not clearly indicate the import failure

Reproduction

1. Deploy the sample to Azure Functions Flex Consumption (Python 3.12+)
2. If github-copilot-sdk fails to install (pip resolution error, platform incompatibility, etc.), the entire app is down
3. Observe: curl https://<app>.azurewebsites.net/ returns Function host is not running

Suggested Fix

Make the Copilot SDK import lazy — only load when the agent endpoint is actually called:

import azure.functions as func

app = func.FunctionApp()

# Lazy init — does not crash the host if copilot SDK is missing
_copilot_client = None

def _get_copilot_client():
    global _copilot_client
    if _copilot_client is None:
        from copilot import CopilotClient
        _copilot_client = CopilotClient()
    return _copilot_client

@app.route(route="ask", methods=["POST"])
async def ask(req: func.HttpRequest) -> func.HttpResponse:
    try:
        client = _get_copilot_client()
        # ... use client
    except ImportError:
        return func.HttpResponse("Copilot SDK not available", status_code=503)

This ensures that if the Copilot SDK is unavailable, only /api/ask fails — other endpoints and timer triggers continue to work normally.

Additional Consideration

The same pattern applies to from copilot.tools import define_tool and from pydantic import BaseModel — these should also be lazily imported if used alongside other endpoints that should remain functional independently.

Environment

• Azure Functions Flex Consumption (Python 3.12+)
• github-copilot-sdk (latest)
• Multi-endpoint function app with timer triggers + HTTP triggers

[copilot-swe-agent]

The agent encountered an error and was unable to start working on this issue: Before you can use Copilot cloud agent, you need to pick a "Usage billed to" option in your Copilot settings. Update your settings, then try again. (Request id: EA99:1124C1:D2F4D4C:D6CAE1F:69D2D67F)

[paulyuk]

The agent encountered an error and was unable to start working on this issue: Before you can use Copilot cloud agent, you need to pick a "Usage billed to" option in your Copilot settings. Update your settings, then try again. (Request id: EA99:1124C1:D2F4D4C:D6CAE1F:69D2D67F)

@copilot ok done