Before the new async-tool mechanism landed, AWSNovaSonicLLMService and
OpenAIRealtimeLLMService honored cancel_on_interruption=False by simply
not cancelling in-flight function calls on interruption — the eventual
result then flowed through the same channel as any synchronous tool
result. The new mechanism (which appends started/intermediate/final
messages to the LLM context as the underlying task progresses) broke
that path: the realtime services didn't know how to interpret those
messages, and the eventual result was never delivered to the provider.
Restore the flag's behavior by teaching both services to detect
async-tool messages in the context and route them appropriately:
- started → skipped silently. The provider already issued the tool call
and natively awaits a result; nothing to send for the started marker.
- final → delivered via the formal tool-result channel. Same path as a
synchronous tool result, just delayed.
Streamed intermediate results (FunctionCallResultProperties(is_final=
False)) are not supported on these realtime services. An intermediate
result is logged as an error and surfaced via push_error, then dropped.
Use a non-realtime LLM service if a tool needs to stream intermediate
results. (Docstrings on register_function, register_direct_function, and
FunctionCallResultProperties.is_final updated to call this out.)
A new shared module pipecat.processors.aggregators.async_tool_messages
is the single source of truth for the on-the-wire payload shape: the
aggregator uses its build_*_message functions when injecting messages,
and the realtime services use parse_message when scanning the context.
Adds two example files exercising a network-delayed weather tool with
each service. The plain realtime-aws-nova-sonic.py example is also
reverted to a synchronous tool call now that the async variant lives in
its own file.
Similar fixes for other realtime services are forthcoming.
