Python: add agent-framework-hosting-responses channel#5639
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eavanvalkenburg wants to merge 6 commits intomicrosoft:feature/python-hostingfrom
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Python: add agent-framework-hosting-responses channel#5639eavanvalkenburg wants to merge 6 commits intomicrosoft:feature/python-hostingfrom
eavanvalkenburg wants to merge 6 commits intomicrosoft:feature/python-hostingfrom
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New ``agent-framework-hosting`` package implementing ADR 0026 / SPEC-002:
the channel-neutral host that lets a single ``Agent`` (or ``Workflow``)
fan out across multiple wire protocols ("channels") behind one Starlette
ASGI app.
Surface (re-exported from ``agent_framework_hosting``):
- ``AgentFrameworkHost`` — wraps a hostable target, mounts channels onto
an ASGI app, owns per-isolation-key ``AgentSession`` reuse, threads
request context (``response_id`` / ``previous_response_id``) into
context providers via an ``ExitStack`` of ``bind_request_context``
calls, and exposes an opt-in Hypercorn ``serve()`` helper (extra
``[serve]``).
- ``Channel`` protocol + ``ChannelContribution`` — the surface a channel
package implements (routes, lifespans, identity hooks, …).
- ``ChannelRequest`` / ``ChannelSession`` / ``ChannelIdentity`` /
``ChannelPush`` / ``ChannelCommand[Context]`` / ``ChannelRunHook`` /
``ChannelStreamTransformHook`` / ``DeliveryReport`` /
``HostedRunResult`` / ``ResponseTarget`` / ``ResponseTargetKind`` /
``apply_run_hook`` — channel-side dataclasses + helpers.
- ``IsolationKeys`` + ``ISOLATION_HEADER_USER`` / ``..._CHAT`` +
``get/set/reset_current_isolation_keys`` — the host's ASGI middleware
reads the ``x-agent-{user,chat}-isolation-key`` headers off each
inbound request and exposes them to the agent stack via a
``ContextVar`` so storage-side providers (e.g.
``FoundryHostedAgentHistoryProvider``) can apply per-tenant
partitioning without channels having to forward anything.
Includes 45 unit tests covering the host, channel contributions,
isolation contextvar, and shared types. Registers the package in
``python/pyproject.toml`` ``[tool.uv.sources]`` and adds the matching
pyright ``executionEnvironments`` entry for tests.
Hypercorn is an optional dependency (``[serve]`` extra); the soft import
in ``serve()`` is annotated for pyright since it isn't on the default
install.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Source-code changes - _suppress_already_consumed: narrow contract — RuntimeError now logs at WARNING with exc_info; non-RuntimeError still logs at exception(). Docstring clarifies that any non-clean teardown is observable. - _BoundResponseStream: add aclose() and route __await__ through get_final_response() so the binding is always released — fixes contextvar leak when channels abandon the stream or use the await-the-stream convenience. - Lifespan: aggregate startup/shutdown callback errors; every callback runs, all failures are logged with their qualname, and the first error is re-raised so Starlette still aborts boot. - _build_run_kwargs: switch session-cache write to dict.setdefault so concurrent racers cannot orphan a session if create_session ever yields. - _deliver_response: introduce DeliveryReport.failed for push outages vs explicit "no link" drops; an outage no longer triggers an originating fallback so the channel can decide degraded behaviour. Test additions - tests/test_isolation.py (new): full coverage of IsolationKeys, the contextvar helpers, header constants, and end-to-end ASGI middleware lift / reset / passthrough. - tests/test_host.py: TestBindRequestContext, TestBoundResponseStream (aclose / __await__ / __getattr__ forwarding / double-close idempotency), TestWrapInputListMessages (list[Message] LAST precedence), TestLifespanAggregation (startup + shutdown). - tests/test_types.py: TestApplyRunHook (sync/async/None), and TestDeliveryReport (new failed field). - Updated test_push_exception_marks_skipped -> test_push_exception_lands_in_failed_no_fallback to match the new delivery contract. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
moonbox3
reviewed
May 6, 2026
- Refactor workflow checkpoint restoration into shared helpers (_restore_workflow_checkpoint for blocking; the streaming sibling drains the rehydration stream) so the blocking and streaming paths rehydrate identically — clarifies the previously inline _maybe_restore by hoisting the pattern next to the blocking call site. - Document that blocking workflow output is text-only by design; richer modalities ride the streaming AgentResponseUpdate channel, which preserves all content parts. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
These review comments were filed on PR-4 (microsoft#5640) but target lines that live in the hosting-core package (PR-2 / microsoft#5638), so the fixes land here and PR-4's stack will pick them up on rebase. - _suppress_already_consumed: narrow the RuntimeError catch to the two documented benign messages (`Inner stream not available`, `Event loop is closed`); any other RuntimeError now logs at ERROR with a full traceback so executor bugs / runner-context state errors / checkpoint RuntimeErrors during the post-run flush no longer masquerade as benign cleanup noise. Still no propagation (we're in an async-generator finally during teardown) — see the docstring. - _restore_workflow_checkpoint{,_streaming}: log a WARNING when a non-None latest checkpoint drains to zero events, so a stale or partially-written checkpoint_id surfaces as an operator signal instead of a silent state-loss. (The `deliver_response` "no destinations resolvable" vs "every destination errored" concern raised in 3198268038 is already addressed by the existing `failed` vs `skipped` distinction surfaced through `DeliveryReport.failed` — see lines 1080-1102 and the `DeliveryReport` docstring.) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
New ``agent-framework-hosting-responses`` package implementing the
OpenAI Responses-shaped HTTP channel for the Hosting framework. Mounts
``POST /responses`` (and a ``/responses/{response_id}`` GET) onto an
``AgentFrameworkHost`` and translates the OpenAI Responses wire shape
to/from the channel-neutral ``ChannelRequest`` / ``HostedRunResult``
plumbing.
Surface (re-exported from ``agent_framework_hosting_responses``):
- ``ResponsesChannel`` -- concrete ``Channel`` implementation. Owns the
Starlette route(s), parses inbound JSON into ``ChannelRequest``, runs
the optional ``ChannelRunHook``, calls back into the
``ChannelContext`` to invoke the agent target, builds Responses
envelopes (sync JSON or SSE), and respects
``DeliveryReport.include_originating`` so cross-channel push routes
only ack to the originating Responses caller.
- The minted ``response_id`` is propagated via the host's ContextVar
machinery so storage-side history providers (e.g.
``FoundryHostedAgentHistoryProvider``) persist envelopes against the
same id the channel returns.
- 48 unit tests covering route wiring, parsing of each Responses input
shape, hook composition, sync vs streaming paths, and originating
vs non-originating delivery branches.
Registers the package in ``python/pyproject.toml`` ``[tool.uv.sources]``
and adds the matching pyright ``executionEnvironments`` entry.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- consume IsolationKeys.chat_key from the host-bound contextvar instead of the raw `x-agent-chat-isolation-key` header off the wire so the host's ASGI isolation middleware (or any operator-supplied replacement) is the authoritative point at which the caller is authenticated and the bucket key is established - expand `response_id_factory` docstring to call out partition co-location vs. partition-ownership enforcement: the channel forwards `previous_response_id` as a hint to the factory; the storage layer validates the embedded partition against the bound user/chat isolation keys - on mid-stream failure, call `deliver_response` with the accumulated text before emitting `response.failed` so host-side history / push-channel state stays consistent with the partial deltas the client already saw Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
eavanvalkenburg
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Motivation and Context
Implements §7 ("Built-in channels — Responses") of SPEC-002 (merged via #5549). Adds the OpenAI Responses-compatible channel so an
AgentFrameworkHostcan be reached by any Responses SDK / OpenAI client.Description
Adds the new
agent-framework-hosting-responsespackage (python/packages/hosting-responses/) with:ResponsesChannel— mountsPOST /responses(configurable), parses the OpenAI Responses request shape intoChannelRequest, and serializes the agent's reply back into a Responses payload (sync or streaming SSE)._parsing.py— request/response translation, isolation-key derivation fromprevious_response_id/safety_identifier, and option scrubbing seam.Stack
PR-3 of 9. Depends on #PR-2 (
feat/hosting-core). Until PR-2 merges, this PR's diff includes that commit too — afterwards the diff shrinks to just this package.Contribution Checklist