Pydantic AI OpenTelemetry instrumentation: retry prompt content is not redacted when `include_content=False`

Summary

Pydantic AI's OpenTelemetry instrumentation supports InstrumentationSettings(include_content=False) to exclude message content — user prompts, model completions, tool call arguments and responses — from exported telemetry, so that agents can be monitored without sending sensitive content to the observability backend.

Retry prompts — the feedback messages Pydantic AI sends back to the model when its output fails validation or an output validator raises ModelRetry — were not covered by this setting when they were not associated with a tool call, as with structured output modes that don't use tool calls (e.g. NativeOutput or PromptedOutput) and output validators applied to text output. Their full content was recorded on model request spans even with include_content=False. Since validation feedback can quote invalid values from the model's response, message content that the setting was configured to withhold could reach the telemetry backend.

Details

Retry prompts without an associated tool call were serialized into span message attributes (such as gen_ai.input.messages and pydantic_ai.all_messages) as regular text parts, and this path did not apply the include_content check that every other message part applies. Retry prompts tied to a tool call, and all other message content, were redacted correctly.

Impact

This does not grant an attacker any new access to the agent or its data: the content is only visible to whoever can read the exported telemetry. The exposure matters when traces are exported to a destination whose audience is broader or less trusted than the agent's own data — a third-party observability vendor or a shared backend — which is the scenario include_content=False exists for. The disclosed content is limited to retry feedback: validation error details, which can quote invalid values from the model's output, or output-validator ModelRetry messages.