[Bug]: SettingsError raised when parsing environment variable observability_exclude_paths in Pydantic settings

[calculus-ask]

🐞 Bug Summary

When starting the application with Gunicorn, initialization fails due to a pydantic_settings.exceptions.SettingsError triggered while parsing the environment variable observability_exclude_paths. The error originates from Pydantic’s environment settings source during the creation of the Settings instance in mcpgateway/config.py. This indicates that the value provided for observability_exclude_paths is not in the expected format or type (for example, a string instead of a list or JSON array). As a result, the configuration cannot be loaded and the application fails to start.

Pls note the above summary is generated by AI using the logs. I have provided logs in Logs section.

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🧩 Affected Component

Select the area of the project impacted:

• [YES ] mcpgateway - API
• [ ] mcpgateway - UI (admin panel)
• [ ] mcpgateway.wrapper - stdio wrapper
• [ ] Federation or Transports
• [ ] CLI, Makefiles, or shell scripts
• [ ] Container setup (Docker/Podman/Compose)
• [ ] Other (explain below)

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🔁 Steps to Reproduce

1. helm upgrade --install mcp-stack . --namespace mcpgw-rbac --create-namespace=false -f values.yaml --wait --timeout 5m --debug

2. PLUGINS_ENABLED: "true"

3. pgadmin: enabled: false

4. mcpFastTimeServer: enabled: false

5. probes: readiness: type: exec command: - sh - -c - pg_isready -U "$POSTGRES_USER"

6. liveness: type: exec command: - sh - -c - pg_isready -U "$POSTGRES_USER"

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🤔 Expected Behavior

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📓 Logs / Error Output

Paste any relevant stack traces or logs here. ⚠️ Do not paste secrets, credentials, or tokens. Traceback (most recent call last): File "/app/.venv/lib64/python3.12/site-packages/gunicorn/app/base.py", line 110, in get_config_from_filename spec.loader.exec_module(mod) File "", line 999, in exec_module File "", line 488, in _call_with_frames_removed File "/app/gunicorn.config.py", line 19, in from mcpgateway.config import settings File "/app/mcpgateway/init.py", line 19, in from mcpgateway import reverse_proxy, wrapper, translate File "/app/mcpgateway/reverse_proxy.py", line 67, in from mcpgateway.services.logging_service import LoggingService File "/app/mcpgateway/services/init.py", line 15, in from mcpgateway.services.gateway_service import GatewayError, GatewayService File "/app/mcpgateway/services/gateway_service.py", line 73, in from mcpgateway.config import settings File "/app/mcpgateway/config.py", line 1564, in settings = get_settings() ^^^^^^^^^^^^^^ File "/app/mcpgateway/config.py", line 1542, in get_settings cfg = Settings() ^^^^^^^^^^ File "/app/mcpgateway/config.py", line 1457, in init super().init(**kwargs) File "/app/.venv/lib64/python3.12/site-packages/pydantic_settings/main.py", line 194, in init **pydantic_self._settings_build_values( ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/app/.venv/lib64/python3.12/site-packages/pydantic_settings/main.py", line 436, in _settings_build_values source_state = source() ^^^^^^^^ File "/app/.venv/lib64/python3.12/site-packages/pydantic_settings/sources/base.py", line 498, in call raise SettingsError( pydantic_settings.exceptions.SettingsError: error parsing value for field "observability_exclude_paths" from source "EnvSettingsSource"

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🧠 Environment Info

You can retrieve most of this from the /version endpoint.

Key	Value
version	v0.9.0
Runtime	e.g. Python 3.11, Gunicorn
Platform / OS	e.g. Ubuntu 22.04
Container	helm, k8 pods

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🧩 Additional Context (optional)

Add any configuration details, flags, or related issues.