feat(langgraph): observe readonly interrupt batches

fixtures/react-parity/README.md

@@ -17,15 +17,20 @@ tools never execute. Private snapshots now include broad readonly application
 `values`, published atomically with messages. Full root state, history and conclusive
 correlated recovery replace the map; unchanged nested data retains identity, and
 token-only updates reuse it without traversal. `undefined` is unobserved state and
-`{}` an observed empty map. Child/update/custom/live-interrupt envelopes are ignored.
+`{}` an observed empty map. Child/update/custom/live-interrupt envelopes do not
+replace application values. A separate readonly interrupt batch now joins the same
+aggregate: root controls accumulate full payloads, and checkpoints/history replace
+them. An empty `__interrupt__` array represents a static breakpoint; explicit empty standalone
+batches clear interrupts. Observation offers no resume or target-selection API.
 Core contracts are unchanged; native structural signatures preserve the concrete
 snapshot extension and tool inference, with the same receiver and lifetime behavior.
 Angular and React borrow the app-owned session and observe it through their native
-lifecycles. The installed consumers run ten scenarios each: inert mount, explicit
+lifecycles. The installed consumers run eleven scenarios each: inert mount, explicit
 history load, equal refresh, empty replacement, text, weather tool
-roundtrip, protected error, held partial text and Stop, reuse after Stop, and
+roundtrip, protected error, held partial text and Stop, full pause batch retained
+after Stop, reuse after Stop, and
 unmount followed by explicit disposal and an aborted post-disposal submission.
-Five live component submissions plus one tool continuation produce six exact wire
+Six live component submissions plus one tool continuation produce seven exact wire
 requests, with one handler invocation and zero page errors or unexpected requests.
 The three explicit loads make three history reads and no run requests or handler
 calls. This is partial T09/T10 coverage: thread switching, pagination, branching,
@@ -40,12 +45,13 @@ exercise that subscription replay. See [runtime/README.md](./runtime/README.md)
 reproduction and [runtime/evidence.json](./runtime/evidence.json) for fresh commands,
 counts, source provenance, cleanup assertions and limitations.
 
-The current inventory has **1,455 records**: the historical 1,438 plus twelve private
+The current inventory has **1,456 records**: the historical 1,438 plus thirteen private
 runtime production sources, three testing helpers, a runtime Vitest config and its
 type-test config asset. Public export occurrences remain 550 with 514 distinct local
 definitions. The original runtime extraction changed fourteen existing export
 records' declaration/import text; history loading and values observation each add
-two private sources and change no legacy public export records. There are no legacy export-name additions
+two private sources; interrupt observation adds one. These increments change no
+legacy public export records. There are no legacy export-name additions
 or removals. Existing task assignments
 are preserved; touched extraction/configuration subsets are in progress, not whole
 T03–T16 completion. Core and native package contracts remain outside this legacy
@@ -169,7 +175,7 @@ type-checks the tarballs outside workspace aliases with `skipLibCheck: false`.
 Its core-only consumer checks all three core exports and rejects extra dependencies.
 The separate Angular check packs the one Angular APF entry and proves CLI
 compilation/linking with `skipLibCheck: false`. Both frameworks now run installed
-production browser apps with the ten shared scenarios. Inferred native contract
+production browser apps with the eleven shared scenarios. Inferred native contract
 probes reject invalid tool names/arguments/results and deep mutations. The private
 runtime's narrow declaration is compiler-generated against installed core declarations,
 never hand-written; the staged SDK bundle is fixture-only. Both inspect consumer
@@ -225,7 +231,7 @@ burst streams and repeated agent/thread disposal.
 
 The foundation branch was `codex/react-support-baseline`; the runtime branch is
 `codex/shared-runtime-quality`, based on `bdcc22ed31aa94f420077e046e88e1481088d453`.
-The current values increment is `codex/langgraph-state-values`; its verified
+The current interrupt increment is `codex/langgraph-interrupt-observation`; its verified
 base and working-source fingerprint are recorded in `runtime/evidence.json`.
 The local maintenance
 branch `codex/angular-maintenance-v0.2` points to released tag `v0.2.0`
@@ -243,7 +249,7 @@ research documents. It is a scope map, not evidence that the tasks are complete.
 T01/T02 describe the foundation increment. The current G1 proof is deliberately limited
 to shared LangGraph text streaming and fixed function-tool execution with borrowed native
 Angular and React bindings: the runtime owns execution while each binding observes
-it. Explicit history loading and application-values observation cover further
+it. Explicit history loading, application-values and interrupt observation cover further
 subsets of T09/T10.
 Renderer reuse and SSR are deferred gates, alongside the broader T01–T39 map.
 This bounded runtime proof does not establish complete migration parity.

fixtures/react-parity/runtime/README.md

@@ -28,7 +28,9 @@ versions come from the root lockfile. Contract probes compile the installed
 public entries with `strict` and `skipLibCheck:false`, standard DOM signals, and
 no workspace aliases. Negative probes check names, arguments, results and deep
 readonly types directly on each binding's inferred snapshot, including broad
-backend values without application-schema inference.
+backend values and interrupt metadata/payloads without application-schema inference.
+The installed fixture shape uses core types only; the compiler-emitted factory
+declaration and native inferred result are checked together, including tool types.
 
 `runtime-entry.ts` is development-only composition around private `createSession`,
 the production `FetchStreamTransport`, and the real LangGraph SDK. A focused
@@ -72,6 +74,26 @@ retaining typed tool results, method receivers and borrowed lifetime semantics.
 The factory and snapshot extension remain private; state writes, application
 schema inference, SSR and package-root cutover remain outside this slice.
 
+`LangGraphSnapshot.interrupts` now observes a readonly batch in that same immutable
+aggregate. Each item retains SDK interrupt metadata and an owned plain payload;
+neither metadata nor payload is a resume command or an inferred application schema.
+Root `values`/`updates` controls must have an own array-valued `__interrupt__` field.
+Separate dynamic batches accumulate: the first occurrence of a string ID wins,
+while anonymous entries stay distinct. An empty `__interrupt__` array replaces
+the batch with the static breakpoint sentinel `{ when: 'breakpoint' }`; the next
+dynamic batch replaces that sentinel. An explicit empty standalone `interrupts`
+batch clears the observed batch.
+
+Authoritative checkpoints and latest history replace interrupts. A valid values
+control takes precedence; otherwise all top-level task interrupt arrays contribute.
+Child namespaces, nested task state and `next` alone do not establish a root pause.
+History pause delivery is derived from the same candidate as messages, values and
+interrupts. Equal refreshes retain identity, and values-only refreshes share the
+unchanged interrupt batch. An accepted new submission clears the prior batch; stop, disposal
+and failures retain the last observed batch. Observation adds no implicit I/O,
+resume or target-selection API. Existing getter/stale-candidate guards, recovery
+correlation, tool handoff and next-user-input behavior remain covered.
+
 The private `LangGraphSession` offers `load({ signal })` only when its transport
 supports history reads. Loading is explicit: construction, mount and subscription
 perform no I/O. The latest checkpoint authoritatively replaces the transcript,
@@ -91,21 +113,22 @@ subset of T10, not thread switching, pagination, branching, state writes,
 interrupt resume, SSR, or a public LangGraph package cutover. Core public contracts
 are unchanged; the native signatures now retain the concrete snapshot extension.
 
-The native fixtures expose Load, Send, Tool, Error, Hold and Stop buttons plus text,
-transcript, values, load completion/error, status, tool result, delivery, submission and
+The native fixtures expose Load, Send, Tool, Error, Hold, Pause and Stop buttons plus text,
+transcript, values, interrupts, load completion/error, status, tool result, delivery, submission and
 handler count outputs. A single app-owned
 session is created outside component lifetime and outside React's StrictMode
 tree; owner buttons perform framework unmount and explicit session disposal.
 React uses a Vite production build. Angular uses the existing consumer template's
 installed Angular CLI application builder and real APF linking, with output in
 `dist/consumer/browser` and input evidence from `dist/consumer/stats.json`.
 
-Both built apps run the same ten browser scenarios in installed Playwright
+Both built apps run the same eleven browser scenarios in installed Playwright
 Chromium: inert mount, explicit history load, equal history refresh, empty history
 replacement, successful text, a real local tool handler and exact
 two-request result continuation, protected visible server error, held streaming
-DOM updates and Stop, reuse after Stop, then unmount/dispose/post-disposal submission.
-Five submissions through the component controls make exactly six run requests
+DOM updates and Stop, the full pause batch retained after Stop, reuse after Stop,
+then unmount/dispose/post-disposal submission.
+Six submissions through the component controls make exactly seven run requests
 (including one tool continuation) and call the handler once. The separate
 post-disposal submit attempt resolves aborted without making a request.
 Three explicit Load clicks make exactly three history reads with `{ limit: 10 }`
@@ -116,7 +139,12 @@ the catalog and actual serialized ToolMessage payload.
 Values assertions distinguish unobserved from empty state, show loaded application
 fields, and verify replacement/deletion across root, tool, held and reused runs.
 Separate native component tests make four history reads to cover a values-only
-refresh with unchanged messages; installed browser scenarios still make three.
+refresh with unchanged messages and interrupts; installed browser scenarios still
+make three. History fixtures contain two separate task payloads and show paused
+delivery. The Pause button sends two separate root controls and renders both
+payloads; Stop retains them without another request, and the next Send clears them.
+Unrelated custom/child noise does not contain a root empty control, because an
+actual empty root `__interrupt__` is a static breakpoint rather than noise.
 
 A small in-process HTTP fixture serves only built artifacts and the expected
 LangGraph run/history routes on dynamic port 0. The held response writes an actual SSE

fixtures/react-parity/runtime/angular-app.ts

@@ -19,11 +19,13 @@ const submit = (input: string) => { submissions += 1; return session.submit(inpu
       <button (click)="submit('Tool')">Tool</button>
       <button (click)="submit('Error')">Error</button>
       <button (click)="submit('Hold')">Hold</button>
+      <button (click)="submit('Pause')">Pause</button>
       <button (click)="stop()">Stop</button>
       <output aria-label="Status" data-testid="status">{{ snapshot().status }}</output>
       <output aria-label="Text" data-testid="text">{{ view().text }}</output>
       <output aria-label="Transcript" data-testid="transcript">{{ view().transcript }}</output>
       <output aria-label="Application values" data-testid="values">{{ view().values }}</output>
+      <output aria-label="Interrupts" data-testid="interrupts">{{ view().interrupts }}</output>
       <output aria-label="Loads finished" data-testid="loads-finished">{{ loadsFinished() }}</output>
       <output aria-label="Load error" data-testid="load-error">{{ loadError() }}</output>
       <output aria-label="Error" data-testid="error">{{ view().error }}</output>