The conditional logic checks for the presence of environment variables using os.getenv() which returns None for unset variables but could also return empty strings. When useMonitoring is false in the Bicep deployment, APPLICATIONINSIGHTS_CONNECTION_STRING will be set to an empty string (see aca.bicep line 66), which would pass this truthy check and call configure_azure_monitor() with an invalid connection string. Update the condition to check for non-empty strings: if os.getenv("APPLICATIONINSIGHTS_CONNECTION_STRING"): should be if os.getenv("APPLICATIONINSIGHTS_CONNECTION_STRING") and os.getenv("APPLICATIONINSIGHTS_CONNECTION_STRING").strip():

[nitpick] The span naming pattern f"tool.{tool_name}", f"resource.{resource_uri}", and f"prompt.{prompt_name}" could lead to high cardinality issues if this middleware is reused in contexts where these identifiers contain dynamic values (e.g., UUIDs, timestamps). For better observability practices, consider using fixed span names (e.g., "tool.call", "resource.read", "prompt.get") with the specific identifier stored only as an attribute, which is already being done.

The Azure SDK tracing implementation setting (settings.tracing_implementation = "opentelemetry") is only configured when using Logfire, but not when using Azure Monitor. This could lead to inconsistent Azure SDK tracing behavior between the two observability platforms. Consider setting this configuration before the conditional blocks (line 33) to ensure Azure SDK always uses OpenTelemetry tracing regardless of the export destination.

The send_to_logfire=True parameter is redundant when LOGFIRE_PROJECT_NAME is set. The logfire.configure() function automatically enables sending to Logfire when a project name is configured. This parameter should be omitted for clarity.

Potential security concern: Tool arguments are logged to OpenTelemetry spans as-is with str(context.message.arguments). This could expose sensitive data (e.g., amounts, descriptions, personal information) to the observability platform. Consider implementing a sanitization strategy or providing configuration to exclude sensitive fields from telemetry data. The comment on line 22-23 acknowledges this but doesn't implement a solution.

The version constraint >=0.49b0 for opentelemetry-instrumentation-starlette doesn't match the actual version in uv.lock which is 0.59b0. Consider updating the constraint to >=0.59b0 to match the locked version and ensure compatibility, or use a more specific constraint like >=0.59b0,<0.60 to prevent unexpected breaking changes from beta versions.

When Application Insights connection string is empty (when useMonitoring is false), the environment variable APPLICATIONINSIGHTS_CONNECTION_STRING will be set to an empty string in the container app. This could potentially trigger the Azure Monitor instrumentation setup in deployed_mcp.py (line 35-37) with an invalid connection string, leading to errors. Consider either not adding the environment variable when it's empty, or checking for non-empty values in the Python code before calling configure_azure_monitor().

APPLICATIONINSIGHTS_CONNECTION_STRING is being exported as a top-level output, which can be viewed by anyone with access to deployment outputs and may be logged or surfaced in tooling. This connection string includes the instrumentation key and can be used to submit telemetry to your Application Insights resource, making it sensitive. Mitigation: avoid outputting this value or mark it as a secure output; instead fetch it securely at runtime or store it in a secret store (e.g., Key Vault) and reference it from deployments.

APPLICATIONINSIGHTS_CONNECTION_STRING is set as a plain environment variable for the container app, increasing chances of accidental exposure via logs, crash dumps, or diagnostics endpoints. Attackers with limited foothold (e.g., read access to env or logs) could exfiltrate it and push malicious telemetry. Fix: store this value as a secret (Container Apps secrets or Key Vault) and reference it from the app; avoid placing it directly in environmentVariables.