2 Commits

Author SHA1 Message Date
Zeren Wang
d3e8e78f3f
feat(authz): middleware-declared tool path Layer 1 now covers tools declared by middlewares (#6105)
* feat(authz): extension tool authorization PR2 — middleware-declared tool path

Layer 1 now covers tools declared by middlewares, which LangChain merges
into the bound tool set after the host's explicit-list filter:

- new agents/middlewares/tool_declarations.py: record the ordinary pass's
  verdict, collect declarations from the built stack, decide only the
  delta seeded by the first pass (a name denied for this build stays
  denied), narrow the stack build-locally on independent state-preserving
  copies (direct __dict__ write, refused up front for tools data
  descriptors, never mutating caller-owned instances), and verify the
  exact bound stack after the final normalization copy.
- IsolatedMiddleware ships a state-preserving __copy__ so narrowing
  survives full/delta normalization and copies of copies.
- TodoMiddleware degrades when write_todos is denied: no system-prompt
  injection, no completion/context-loss reminders, no jump_to.
- Layer 2 forwards host-resolved tool provenance into AuthzRequest.context
  and binds the infrastructure exemption to the concrete host-created
  tool object instead of a name set (tool=None goes to the provider).
- Wired into all four assembly paths (lead x2, native subagent with the
  decision offloaded via asyncio.to_thread, DeerFlowClient).

Tests: new test_middleware_declared_tools.py (35) and
test_layer2_tool_provenance.py (7); blocking-IO anchor pinning the
subagent offload (teeth verified red->green); placement-guarantee and
enforcement suites extended; executor test doubles converted for the
async _create_agent. Behavior change called out in CHANGELOG: with
authorization enabled and a tools policy that excludes write_todos,
plan-mode builds no longer bind it (built-in RBAC default unchanged).

* fix(authz): close residual gaps from review — narrow non-collectable declarations, dedupe candidates, warn on skipped pass

- apply_declared_tool_view now removes non-BaseTool declarations from the
  bound view when authorization is enabled (they would otherwise bind via
  LangChain's create_tool auto-conversion with no provider decision);
  verify_declared_tool_view fails loudly if one survives normalization
- decide_declared_tools dedupes never-submitted names so the provider sees
  each candidate once
- subagent executor logs a warning when the provider is set but the seeded
  Layer-1 state is missing, instead of skipping the declaration pass silently
- docs: middleware-declared tools must be BaseTool instances with usable names

* fix(authz): fail loudly on non-list/tuple middleware tools declarations

_iter_declared warned and returned () for a 'tools' attribute that is not
a list/tuple, but LangChain's factory iterates the attribute as-is — so a
set/generator/dict_values declaration bound with no Layer-1 decision.
Raise DeclaredToolViewError instead, matching the module's fail-loud
standard for every other un-narrowable shape. Disabled path remains a
strict no-op. Docs updated to match.
2026-10-01 18:26:58 +08:00
Nan Gao
7389331e65
feat(extensions): observe task lifecycle and system model calls (#4684)
* feat(extensions): observe task lifecycle and system model calls

PR 1 (#4636) gave extensions a middleware chain, and a middleware only sees
what passes through the agent graph. Two runtime surfaces stay invisible to
it: when a lead run or a subagent begins and ends, and the DeerFlow-owned
model calls made outside the graph. This slice adds both, with no new
Gateway surface -- routers, services, and the reference extension stay in
PR 3.

Contract (deerflow-extension-api 0.1.1)
---------------------------------------
Two contribution kinds join `middlewares` on the registry:
`task_lifecycle` (`on_task_start` / `on_task_stop`, receiving a `TaskInfo`
and a conservative `TaskOutcome` of completed / aborted / failed) and
`system_model_observer` (`on_system_model_call`, receiving a
`SystemOperationKind`, a `SystemModelRequest` snapshot, and a
`SystemModelResult` carrying either the response or the provider exception
plus a duration).

`SystemModelRequest.messages` normalizes to a tuple at construction. Goal
evaluation and memory extraction pass a message list while title generation
and summarization pass one prompt string, and a bare `str` already satisfies
`Sequence` -- without normalization an observer iterating `request.messages`
would silently walk characters. Copying also makes the frozen snapshot
immutable in fact rather than only by declaration, since observations may run
after the call site returns and keeps mutating its own list.

Registry marks and rollbacks become per-bucket and positional, so an
`install()` that fails after registering two different kinds cannot leave one
of them behind. `needs_task_store` now covers all three kinds: a deployment
that registers only lifecycle hooks still gets a task store.

Task lifecycle
--------------
The lead worker notifies start after the run has started and stop after
completion persistence and the completion hook, but before clearing the
finalizing barrier and publishing the stream end -- holding the barrier
across stop is what keeps a same-thread replacement run from overlapping this
task's lifecycle. Cancellation raised out of the stop notification is
deferred, not propagated in place, so a cancelled run still clears the
barrier and emits its end frame. A subagent with a parent `run_id` wraps its
execution in the same pair inside `finally`, reporting `parent_task_id` so a
delegation tree is reconstructable; a subagent without a `run_id` (embedded
client, standalone LangGraph Server) logs and skips rather than inventing a
parent. Contributors run in registration order inside one shared 3s budget
and every failure is logged and failed open.

System model calls
------------------
Four kinds cover the model calls the middleware chain cannot see: goal
evaluation, memory extraction, title generation, and summarization. Each site
reports both terminal paths without changing the provider exception the host
observes, short-circuits on `has_system_model_observers`, and passes the live
task store when the runtime has one (detached work gets an isolated store).
The sync summarization half stays unobserved on purpose -- it and its only
host caller are the sync side of an async-only runtime, so notifying there
would block a thread on a call site the host never reaches; the reason is
recorded at the call site.

The DeerMem backend must stay vendorable and cannot import the extension API,
so it reports through a new `MemoryCallbacks.on_memory_llm_result` host hook
that the DeerFlow-side callbacks translate into an observation.

Notification loop
-----------------
Extension resources must be touched on the loop that created them, but
subagents can execute on isolated loops and DeerMem runs on a worker thread.
The Gateway registers its serving loop before any runtime dependency starts
and resets it last through the exit stack, so every startup-failure and
cancellation path is covered. Awaited hooks raised on another loop are
dispatched across with `run_coroutine_threadsafe` and awaited under the same
budget; synchronous sites submit fire-and-forget work. Shutdown stops
accepting detached observations before the memory flush -- that flush runs on
a worker thread and can emit memory observations -- while keeping the loop
alive for awaited task hooks until run and subagent drain completes.

Tests
-----
`test_extension_task_lifecycle.py`, `test_extension_subagent_lifecycle.py`,
and `test_extension_system_model_calls.py` cover ordering, fail-open, budget
exhaustion, snapshot binding under a concurrent singleton replacement, the
loop-dispatch and shutdown-suspension paths, and both terminal paths at every
call site. `test_gateway_run_drain_shutdown.py` pins the stop-before-barrier
and drain ordering.

* fix(extensions): decide notification fail-open by origin, observe cancellation

`_notify_each` only guarded `Exception`, so a contributor letting a
`CancelledError` escape — an extension implementing an internal timeout with
cancellation, say — skipped its successors and reached the worker's
deferred-interrupt path, ending an otherwise successful run as cancelled.
Fail-open is about where a failure came from, not its base class: only a
genuine cancellation of the host task increments `Task.cancelling()`, so
propagate on that and contain everything else. `KeyboardInterrupt` /
`SystemExit` still propagate.

`observe_system_model_call` skipped observers on cancellation for the same
base-class reason, leaving goal / title / summarization silent on a terminal
path that is routine — interrupt/rollback admission and shutdown both cancel
the run task, with the provider tokens already spent. Awaiting observers there
is unreliable (a repeated cancel interrupts that await before any of them
runs), so report through the same non-blocking submission the synchronous
memory bridge uses, then propagate the cancellation untouched.

DeerMem keeps `BaseException` around its provider call, now with the reason
recorded: that path runs on a worker thread, where cancelling the awaiting
side never interrupts the running thread, so `CancelledError` cannot arrive
at all. Its host-hook wrapper narrows to `Exception` — only the hook's own
failures are non-fatal, and an observability path must not swallow a process
teardown signal.

* fix(extensions): warn on budget exhaustion, scope observer logs by task, propagate teardown

Review response on #4684:

- The memory observation bridge caught BaseException, which would swallow
  a teardown signal raised while dispatching; it now catches Exception,
  matching the boundary the DeerMem-side call site documents and tests.
- A notification-budget timeout raised mid-hook fell into the generic
  hook-failure path and logged an asyncio-internal traceback; it now logs
  a warning like the pre-hook budget skip, while a TimeoutError a
  contributor raises on its own stays classified as a hook failure.
- System model observer logs passed the operation kind as the task id,
  so log lines said "task goal/title/..."; they now carry the task
  scope id alongside the kind.
2026-08-11 16:33:22 +08:00