Replaces the prior "log a warning and skip" approach with actual handling
of async-tool messages on Ultravox.
The catch with Ultravox is that its API freezes the conversation between
client_tool_invocation and the matching client_tool_result — there's no
"keep talking while the tool runs" channel like NON_BLOCKING on Gemini
or function_call_output-without-blocking on OpenAI Realtime. So:
- When the model invokes an async-registered function (cancel_on_inter
ruption=False), the service immediately ships a placeholder
client_tool_result that tells the model "the actual result isn't
ready yet; a follow-up will arrive shortly; keep the conversation
going". This unfreezes the conversation. The placeholder is sent
from _handle_tool_invocation, since the started async-tool message
doesn't reach the context-frame path until later.
- When the real tool finishes, the final async-tool message lands in
the context. _handle_context now forward-iterates and routes
async-tool messages: started is a no-op (placeholder already sent),
intermediate is logged-as-error and dropped (matching the other
realtime services), and final is injected as user-side text via
user_text_message with bracketed framing — the only mechanism
Ultravox offers for adding non-tool input mid-conversation.
Hoists the registry-lookup helper to LLMService as
_function_is_async(name) so future services can use the same pattern
without re-implementing it.
Adds an async-tool example file for Ultravox modeled on the existing
ones for the other realtime services.
Applies the same async-tool message routing introduced for AWSNovaSonicLLMService
and OpenAIRealtimeLLMService to additional realtime LLM services where the
flag's intent ("keep talking while the tool runs") is achievable:
- GrokRealtimeLLMService (xAI Realtime — also benefits the deprecated Grok
alias since it re-exports the xAI module)
- AzureRealtimeLLMService picks up the fix transitively by inheriting from
OpenAIRealtimeLLMService — no code change needed.
GrokRealtimeLLMService's _process_completed_function_calls now matches
the canonical pattern: skip LLMSpecificMessage, detect async-tool messages
via parse_message and route them — started skipped silently, intermediate
logged as an error and surfaced via push_error, final delivered through
the same channel as a synchronous result.
UltravoxRealtimeLLMService instead gets a one-time warning when async-tool
messages appear in the context. The Ultravox API freezes the conversation
during tool execution
(https://docs.ultravox.ai/tools/async-tools#custom-tool-timeouts), so the
flag's "keep talking while the tool runs" intent isn't achievable there —
applying the same code pattern would mislead users into expecting a UX
Ultravox can't deliver. Surfacing a clear warning is the right behavior
until Ultravox grows true async tool support.
Adds async-tool example files for Grok and Azure modeled on the existing
Nova Sonic / OpenAI Realtime ones (10s simulated network delay, weather
tool registered with cancel_on_interruption=False).
Two services remain excluded:
- GeminiLiveLLMService — the async-tool path needs deeper investigation.
- InworldRealtimeLLMService — appears to have a pre-existing problem
with even simple synchronous tool calling on its Realtime API (the
request reaches the server fine, but response generation fails with a
generic server_error).
