The presence-roster work (#1460) moved the delivery pump into
CoreStreamProcessor.openConnection; re-applied the D20 protocol there:
batches carry state read alongside streamMaxOffset, every subscription
gets an initial push, events: false is state-only mode. subscribe()
keeps both new options (events + subscriber) end to end, including the
capnweb RpcTarget override.

Tests reconciled with presence facts (every subscribe/unsubscribe now
appends a fact, so exact batch counts/empty-events assertions raced):
assert on delivered content and per-batch invariants instead.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…ook (useItx) (#1472)

## What

Two halves of one decision: stream subscriptions become the ONE reactive
primitive, and the browser layer collapses onto it — one hook, no query
cache, no SSR, no reconnect machinery. Net **−951 lines** against main,
with the deleted test files making the suite smaller than it was.

### Half 1 — the protocol: subscriptions carry reduced state (DECISIONS
D20)

- **Every batch carries `state`.** The pump (now in
`CoreStreamProcessor.openConnection` after the presence-roster merge)
attaches the core reduced state to every delivery, read in the same
synchronous block as `streamMaxOffset` so the two always correspond. The
OS capability projects it through the exact mapping `getState()` uses
(`coreStateToStreamState` is the single shared projection), so
subscribe-state === getState-state by construction.
- **`events: false` = state-only mode.** Same batches with `events: []`
(empty array, not omitted — shape stability), one delivery per state
advance with missed appends coalesced. Replay without events is
meaningless, so state-only subscriptions are implicitly live-from-now.
- **The initial push.** EVERY subscription immediately receives one
batch (current state + `streamMaxOffset`, folded into the replay batch
when there is one), so a subscriber paints its first render from the
subscription alone — no separate getState call.
- **Kernel surface.** `ItxStream.subscribe(onBatch, { afterOffset,
events? })` plus `ItxStream.onStateChange(cb)` sugar (state-only
subscribe with explicit callback-stub retention).

### Half 2 — the browser layer: ONE hook (DECISIONS D21, supersedes D19
and one-socket-per-tab)

The TanStack-Query-for-itx + SSR + shared-socket architecture was too
complicated. `apps/os/src/itx/use-itx.ts` replaces all of it:

- **`useItx(context?)`** suspends (React 19 `use()` on a per-context
module-singleton promise) until a WebSocket to `/api/itx[/<ctx>]` is
connected, and returns the live `RpcStub<Itx>`.
`getBrowserItx(context?)` is the same singleton for non-hook code.
That's the whole API.
- **No reconnect machinery.** Socket death evicts the map entry;
subscribers re-render via useSyncExternalStore, dial fresh, re-suspend —
the initial push repaints them with current state. No backoff, no offset
resume, no liveness probes. Multiple sockets per tab are fine.
- **No SSR for itx components — the hook THROWS on the server.** A
forever-pending `use()` during streaming SSR would hold the response
stream open (React waits for suspended boundaries); a throw inside a
Suspense boundary streams the fallback and recovers client-side, and
outside one it fails loudly instead of hanging the worker. Consumers sit
under `ssr: false` routes (streams pages), `<ClientOnly>` (the repl's
activity tail), or the admin layout's client-only connect gate.

Consumers rewritten: the stream tree browser is now LIVE (one
`onStateChange` per loaded node, refresh = re-subscribe; react-query
gone), the streams index/detail routes use `useItx` under Suspense
(loader prefetch deleted), breadcrumb popovers fetch childPaths on open
into local state, and `ItxActivityTail` is a kernel `subscribe` from
"start" into component state (500-event cap, offset-deduped
re-subscribe). The repl keeps its own `createBrowserReplSession` — it
needs dispose/reconnect-on-demand semantics the singleton deliberately
lacks.

### Deleted

`apps/os/src/itx/react/` (provider, backoff-reconnect connection, query
bridge, stream-tail multiplexer, `useStreamEvents`, all their tests),
`itx/server.ts` (`getServerItx`), `itx/loader.ts`
(`getLoaderItx`/`prefetchItxQuery`), `lib/itx-queries.ts`, and the
`itx-server-handle` worker test harness (+ its package.json script and
knip entries). `itx/errors.ts` stays (error codes still matter to catch
blocks); its test moved next to it.

### Docs

DECISIONS **D20** + **D21**, `itx-orpc-replacement-plan.md` browser/SSR
sections rewritten to the one-hook model, `tasks/os-orpc-teardown.md`
updated (getServerItx marked superseded; route-conversion guidance now
references `useItx`).

## Notes

- Merged with `main`'s subscriber-presence work (#1460): the D20 pump
changes were re-applied inside `CoreStreamProcessor.openConnection`, and
`subscribe()` carries both new options (`events`, `subscriber`). Tests
that asserted exact batch counts/empty-events were reconciled with
presence facts (every subscribe/unsubscribe appends one) to assert
delivered content and per-batch invariants instead.
- `subscribeOutbound` (processor hosts) shares the pump, so outbound
connections also get state-bearing batches and an initial `events: []`
batch on (re)connect — `StreamProcessor.ingest` no-ops on empty batches.

## Tests

- **Pump level** (`packages/streams` stream.workers.test.ts): state
matches the DO's own reduced state on every batch; immediate initial
batch on live-only subscribe; initial push folds into replay; `events:
false` state-only mode — all green alongside main's presence-roster
tests.
- **Capability loopback** (`pnpm test:itx-stream-subscribe`, 13
passing): batch state === getState shape end-to-end, live-only initial
push, state-only mode, `onStateChange` across real Workers RPC hops.
- **Hook core** (`apps/os/src/itx/use-itx.test.ts`): the connection map
— stable entry per context, eviction + notification on death,
identity-guarded eviction, fresh dial after eviction.
- **e2e** (itx-subscribe.e2e.test.ts, runs in preview CI) unchanged.
- Full: `pnpm typecheck && pnpm lint && pnpm knip && pnpm format && pnpm
test` all green at root after merging main.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Large architectural cutover across streams protocol, OS UI, and
deleted SSR/prefetch paths; live views may stall until refresh if Stream
DOs evict without server-side subscription recovery.
> 
> **Overview**
> **Stream subscriptions** now carry reduced **`state`** on every batch
(same shape as `getState()`), with an **immediate initial push** so UIs
can paint without a separate fetch. **`events: false`** is state-only
mode (live-from-now, coalesced updates). **`ItxStream.onStateChange`**
is the reactive sugar on top.
> 
> **Browser itx** collapses to **`useItx` / `getBrowserItx`**:
per-context WebSocket singletons, Suspense until connected, **no SSR**
(throws on server), **no** TanStack Query bridge, reconnect backoff,
stream-tail multiplexer, or **`getServerItx`** loader prefetch.
**`ItxProvider`** and **`~/itx/react/`** are removed.
> 
> **UI** is rewired: the stream tree uses live **`onStateChange`** per
node; streams routes are **`ssr: false`** + Suspense; breadcrumbs
**`getState`** on popover open; **`ItxActivityTail`** uses kernel
**`subscribe`** from `"start"`. Docs/decisions (**D20**, **D21**) and
tests are updated; the itx-server-handle harness is deleted.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
3d7754a. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

<!-- CLOUDFLARE_PREVIEW -->
## Environment Config Lease
<!-- CLOUDFLARE_PREVIEW_STATE -->
<!--
{
  "apps": {
    "os": {
      "appDisplayName": "OS",
      "appSlug": "os",
      "status": "deployed",
      "updatedAt": "2026-06-10T20:20:50.857Z",
      "headSha": "3d7754a7838bb5e0da93ea4cf213644ba5559652",
      "message": null,
      "publicUrl": "https://os.iterate-preview-6.com",
"runUrl": "https://github.com/iterate/iterate/actions/runs/27303571586",
      "shortSha": "3d7754a"
    }
  },
  "environmentConfigLease": {
    "dopplerConfig": "preview_6",
    "leasedUntil": 1781126280948,
    "leaseId": "d920039e-82ea-4bbd-b93a-affdf57e3fc1",
    "slug": "preview-6",
    "type": "environment-config-lease"
  }
}
-->
<!-- /CLOUDFLARE_PREVIEW_STATE -->
Lease: `preview-6`
Doppler config: `preview_6`
Type: `environment-config-lease`
Leased until: 2026-06-10T21:18:00.948Z

### OS
Status: deployed
Commit: `3d7754a`
Preview: https://os.iterate-preview-6.com
[Workflow
run](https://github.com/iterate/iterate/actions/runs/27303571586)
Updated: 2026-06-10T20:20:50.857Z
<!-- /CLOUDFLARE_PREVIEW -->

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

#1479)

## Streams review — Stages 4–7 (browser robustness, perf, dead code,
docs)

The final batch of the `packages/streams` adversarial review
(`tasks/streams-review-fixes.md`), bundled into one PR per request.
Stages 0/1/3 already shipped (#1455, #1458, #1459); **Stage 2 (lazy
init) was abandoned** — #1460's subscriber-presence model appends a
`subscriber-connected` fact on every `subscribe()`, which fundamentally
conflicts with "don't initialize storage until the first `append()`".
`created`/`woken` stay eager.

All findings were re-verified against current `main` after #1460/#1457
moved the codebase; items those PRs already fixed or made obsolete are
called out below.

### Stage 4 — browser-runtime correctness
- **C1-browser** — the server delivery pump is fire-and-forget for
inbound subscribers and never reports a failed `ingest`, so a browser
mirror that fails to apply a batch silently desyncs forever. The browser
now self-heals: `ingestWithSelfHeal` resubscribes from the persisted
checkpoint with bounded exponential backoff on ingest failure.
- **B1** — connection-epoch guard so a stale connection's late status
callback can't clobber the live connection.
- **B2** — `appendBatch`/`runtimeState` await connection readiness
(`whenStreamReady`) instead of throwing "disposed" during a transient
reconnect; only throw when actually disposed.
- **B3** — the `ROLLBACK` in `stream-db.worker.ts` `batch()` is now in
its own try/catch so it can't mask the original error (which
`withBusyRetry`/`isBusyError` need to see).
- **B4** — reconcile guards on stream incarnation (server `createdAt` +
a `mirror_meta` table): rebuild the mirror on incarnation change rather
than trusting the offset comparison after a `reset()`.
- **B5** — `AbortSignal` on the Web Lock request (released on disposal)
+ the request rejection is surfaced instead of `void`-swallowed.
- **B6** — query lifecycle: arm GC at query creation (not only on
unsubscribe), skip listenerless queries in `#onChange`, and
equality-check before notifying to avoid spurious `useSyncExternalStore`
churn.

### Stage 5 — performance
- **P1** — `browser-event-feed` O(n²) write amplification: coalesce to
one op per `local_index` (was a cumulative op per event, each
re-serializing the whole accumulated array).
- **P2** — bound group rows with `MAX_GROUP_EVENTS = 200` so one
dominant event type can't grow a single blob unboundedly.
- **P3** — drop the per-event full-state `stateSchema.parse` in core
`reduce`; state is validated only at the KV/recovery trust boundary now.
- **P4** — already fixed by #1460 (subscribe override forwards
`eventTypes`; filtering is server-side). No change.

### Stage 6 — dead code / elegance (~247 lines deleted)
- **E1** dead exports in `shared/stream-processors.ts`; **E2**
`waitForOpen`; **E3** unreachable circuit-breaker `paused` guard; **E5**
dead `waitForEvent`/`messageInbox.error` machinery in `subscription.ts`;
**E6** redundant circuit-breaker `consumes` entries.
- **E4 obsolete** (#1460 removed `processor-registered`; the shared
`circuit-breaker-types` is a live, separately-imported hierarchy, not
dead code). **E7 declined** — post-#1460 the subscribe override
genuinely needs to retain the client callback / wire `onRpcBroken`, so
folding it into the generic `makeRpcTargetClass` isn't worth it.

### Stage 7 — docs
- **D1** `design.md`: status banner, fixed 1-based offsets + core-event
examples, the callable subscriber spec, SQLite/512KB-chunking storage,
live-tail `replayAfterOffset` default, OPFS mirror; superseded banners
on the never-shipped `implementProcessor`/`connectStream` sections.
- **D2** `README.md`: real browser export
(`withStreamConnectionFromBrowser`), sync `Disposable`, `?path=` route
map; new "Append & subscription semantics" section (D5).
- **D3** ADR 0001 superseded with the shipped per-`(namespace, path,
slug)` singleton model.
- **D4** remaining comment drift (`beforeAppend`→`validateAppend`,
`afterAppendBatch`→`processEventBatch`).

### Testing
`pnpm typecheck`, `pnpm lint`, node (79) + workers (15) suites, and
example-app typecheck all green. Example-app Playwright e2e run locally
against a clean `vite dev` (real Stream DO via Miniflare): **26
passed**. `origin/main` merged in (no `packages/streams` overlap; the
new project-config stream-processor consumers don't touch any deleted
exports).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Touches browser reconnect, mirror discard, and ingest self-heal paths
that affect live viewers and local SQLite mirrors; server stream DO
behavior is mostly unchanged aside from core reduce hot-path
optimization.
> 
> **Overview**
> Closes out **Stages 4–7** of the `packages/streams` adversarial
review: browser mirror reliability, feed/core hot-path perf, dead-code
removal, and doc alignment. Stage 2 (lazy stream init) stays
**abandoned** and is only noted in `tasks/streams-review-fixes.md`.
> 
> **Browser runtime** (`stream-browser-store.ts` and friends) is
reworked so the OPFS mirror can recover instead of silently drifting.
Inbound delivery is fire-and-forget, so failed `ingest` now triggers
**`ingestWithSelfHeal`** (resubscribe from the last checkpoint with
capped exponential backoff). Reconnects go through one
**`scheduleReconnect`** path with a **connection epoch** so stale
WebSocket callbacks cannot tear down the replacement connection.
**`appendBatch` / `runtimeState`** use **`callWhenReady`** /
**`whenStreamReady`** during transient reconnects instead of throwing
“disposed”. Mirror trust uses server **`createdAt`** as incarnation
identity via new **`mirror_meta`** helpers in
**`stream-browser-db.ts`**. Web Lock **`release()`** aborts pending lock
requests; the SQLite worker preserves the original batch error if
`ROLLBACK` fails; reactive queries GC earlier, skip unobserved
refreshes, and avoid notify when snapshots are unchanged.
> 
> **Performance:** `browser-event-feed` **`planFeedOps`** coalesces one
SQL op per group row and caps groups at **`MAX_GROUP_EVENTS` (200)**.
Core **`reduce`** no longer exit-parses the full `stateSchema` on every
appended event.
> 
> **Cleanup:** ~247 lines removed (unused `stream-processors` exports,
`waitForOpen`, dead subscription `waitForEvent` machinery, trimmed
circuit-breaker `consumes` and an unreachable guard). **Docs:** `README`
(real browser API, `?path=` routes, append/subscription semantics),
`design.md` and ADR 0001 marked superseded where they diverge from
shipped code.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
f52f305. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

<!-- CLOUDFLARE_PREVIEW -->
## Environment Config Lease
<!-- CLOUDFLARE_PREVIEW_STATE -->
<!--
{
  "apps": {
    "os": {
      "appDisplayName": "OS",
      "appSlug": "os",
      "status": "deployed",
      "updatedAt": "2026-06-10T22:02:58.860Z",
      "headSha": "f52f305a9f1ab43c9749f80e30bcd96705cbce59",
      "message": null,
      "publicUrl": "https://os.iterate-preview-3.com",
"runUrl": "https://github.com/iterate/iterate/actions/runs/27309066809",
      "shortSha": "f52f305"
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  "environmentConfigLease": {
    "dopplerConfig": "preview_3",
    "leasedUntil": 1781132382486,
    "leaseId": "52648479-bd91-469d-91e5-a3338534feae",
    "slug": "preview-3",
    "type": "environment-config-lease"
  }
}
-->
<!-- /CLOUDFLARE_PREVIEW_STATE -->
Lease: `preview-3`
Doppler config: `preview_3`
Type: `environment-config-lease`
Leased until: 2026-06-10T22:59:42.486Z

### OS
Status: deployed
Commit: `f52f305`
Preview: https://os.iterate-preview-3.com
[Workflow
run](https://github.com/iterate/iterate/actions/runs/27309066809)
Updated: 2026-06-10T22:02:58.860Z
<!-- /CLOUDFLARE_PREVIEW -->

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

…1483)

Steps B and C of the agents roadmap (after #1460 and #1475): the LLM
request handoff stops embedding the conversation, and the two LLM
request processors become deliberate, tidy siblings sharing pure
helpers.

## Request-by-reference (no more embedded body)

`agent/llm-request-requested` used to carry the full chat request. Since
the conversation grows with the stream, every request stored a complete
copy of it — O(N²) stream growth. The `llmRequestId` already IS the
requested event's offset, so the body is redundant: providers can
rebuild it from committed history.

Before:

```ts
// agent processor, on handoff
payload: {
  model,
  runOpts,
  body: buildLlmChatRequest(stateAtRequest), // full conversation, every time
}
```

After:

```ts
// agent processor: just the reference + how to run it
payload: { model: stateAtRequest.llmConfig.model, runOpts: stateAtRequest.llmConfig.runOpts }

// provider, at execution time (both cloudflare-ai and openai-ws):
// Request-by-reference: the requested event carries no body; rebuild the
// chat request from committed history up to the request's own offset.
const body = buildAgentLlmRequestBody({
  events: await this.deps.readStreamEvents(),
  llmRequestId, // === the requested event's offset
});
```

The rebuild reduces history `events.filter((e) => e.offset <=
llmRequestId)` through the same `reduceAgentEvents` +
`buildLlmChatRequest` pair the agent itself uses, so the model-visible
context is reproducible from the stream forever — including for
crash-recovery retries, which re-derive exactly what the dead
incarnation would have sent.

**Breaking change** to the `agent/llm-request-requested` payload (and
`cloudflare-ai/llm-request-started`, which also embedded the body). No
backcompat bridge; prd gets redeployed.

## Providers as siblings, not an abstraction

`cloudflare-ai` and `openai-ws` were ~500/790-line copy-pasted state
machines. Rather than an abstract base class, they're now deliberate
siblings: same method names, same control flow, same comments where the
logic matches — each keeps its own event types (which scales better as
providers diverge) and its own transport (one `AI.run()` call vs a
shared Responses WebSocket). What they share are four stateless
functions in `llm-request-helpers.ts`:

```ts
buildAgentLlmRequestBody({ events, llmRequestId });     // the request-by-reference rebuild
isAgentLlmRequestStillCurrent({ events, llmRequestId }); // stale-output guard before agent-visible appends
findDanglingLlmRequestIds({ requests, executedLlmRequestIds }); // crash-recovery candidates
parseLlmRequestRequestedEventAt({ events, llmRequestId });      // typed re-derivation for recovery
```

Both implementation files open with the same note: *"When you fix
something here, check whether the sibling needs the same fix."*

## Bounded execution-claims set

`#executedLlmRequestIds` (the instance-scoped set distinguishing "this
incarnation is executing it" from "a dead one was") previously only
grew. Both siblings now drop a claim when the request's own completed
fact reduces back:

```ts
case "events.iterate.com/cloudflare-ai/llm-request-completed":
  // The completed fact is durable; this instance can never need to
  // (re-)execute this request again, so drop the claim — this is what
  // keeps the executed set bounded.
  this.#executedLlmRequestIds.delete(event.payload.llmRequestId);
  return;
```

## Tests

- New in both provider suites: *rebuilds the chat request from history
up to the request's offset* — history rows after the requested event's
offset are excluded from what the model sees.
- The agent handoff test now asserts the requested payload is `{ model,
runOpts }` with no `body`.
- Provider fixtures lost their embedded bodies; conversation content now
flows through `readStreamEvents` history, matching production.

`pnpm typecheck && pnpm lint && pnpm format && pnpm test` all green.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Breaking event payload shapes for `llm-request-requested` and provider
started events; correctness now depends on history reads and
offset-bounded rebuild at execution time, including crash recovery
paths.
> 
> **Overview**
> **Request-by-reference LLM handoff** stops embedding the full
conversation on `agent/llm-request-requested` (and drops `body` from
`cloudflare-ai/llm-request-started`). Handoffs are now `{ model, runOpts
}` only; `llmRequestId` stays the requested event’s offset, and
**cloudflare-ai** / **openai-ws** rebuild model input at execution via
shared `llm-request-helpers.ts` (`buildAgentLlmRequestBody` reduces
history with `offset <= llmRequestId`).
> 
> The two provider processors are aligned as **siblings** (shared
helpers for rebuild, still-current checks, dangling recovery, typed
re-parse) instead of duplicated logic. **`#executedLlmRequestIds`** now
drops entries when each request’s provider **completed** event reduces,
so long-lived instances don’t grow the claim set forever.
> 
> Tests assert handoff payloads have no `body` and that providers
exclude stream rows after the request offset when building chat input.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
83ed554. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

<!-- CLOUDFLARE_PREVIEW -->
## Environment Config Lease
<!-- CLOUDFLARE_PREVIEW_STATE -->
<!--
{
  "apps": {
    "os": {
      "appDisplayName": "OS",
      "appSlug": "os",
      "status": "deployed",
      "updatedAt": "2026-06-10T22:06:49.277Z",
      "headSha": "83ed55497ec2f4d04aeb172f36d2dddd34b8dcfc",
      "message": null,
      "publicUrl": "https://os.iterate-preview-7.com",
"runUrl": "https://github.com/iterate/iterate/actions/runs/27309177659",
      "shortSha": "83ed554"
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    "leasedUntil": 1781132576419,
    "leaseId": "7f1ba814-5c43-4cdd-ae72-2f569050a9d5",
    "slug": "preview-7",
    "type": "environment-config-lease"
  }
}
-->
<!-- /CLOUDFLARE_PREVIEW_STATE -->
Lease: `preview-7`
Doppler config: `preview_7`
Type: `environment-config-lease`
Leased until: 2026-06-10T23:02:56.419Z

### OS
Status: deployed
Commit: `83ed554`
Preview: https://os.iterate-preview-7.com
[Workflow
run](https://github.com/iterate/iterate/actions/runs/27309177659)
Updated: 2026-06-10T22:06:49.277Z
<!-- /CLOUDFLARE_PREVIEW -->

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

The last batch of outstanding work from the agents audit (after #1460,
#1475, #1483): the section-3 dead-code sweep and the UI shrink. Net
**−188 lines** (−503/+315).

## One agent setup form

`agents/new.tsx` and `agents/new-preset.tsx` were ~270-line,
~90%-identical forms (provider/model/runOpts/system-prompt/custom-events
fields plus the YAML preview pane). They now share one
`AgentSetupFormPage` component; each route keeps only what genuinely
differs — its path normalization, its preview builder, and its submit
mutation:

```tsx
<AgentSetupFormPage
  title="New Agent"
  pathLabel="Agent path"
  buildPreview={(values) => buildPreviewEvents({ projectId: project.id, values })}
  submitIdleLabel="Create agent"
  isPending={createAgent.isPending}
  onSubmit={({ preview }) => createAgent.mutate(preview)}
  ...
/>
```

The routes drop from ~270 lines each to ~125, and the next form tweak
happens once instead of twice.

## Legacy Slack preset filter deleted

`agent-presets.ts` carried `isLegacyGeneratedSlackOpenAiPreset` — a
content-sniffing filter that suppressed an old auto-generated
`/agents/slack` preset by matching its system-prompt text. Checked prd
before deleting: the iterate project has **zero** stored presets, so the
filter guards nothing. The intentional behavior next to it (Slack agents
never inherit the generic `/agents` preset) stays, with its tests.

## Stale migration headers

Every processor under
`apps/os/src/domains/{agents,slack}/stream-processors/` opened with
"Migrated from `packages/shared/src/stream-processors/...`" — a
directory that no longer exists. Those provenance paragraphs are gone.
Where they carried a live constraint, the constraint survives in its own
words:

```ts
// Appended event types, payload shapes, and idempotency-key derivations
// (`agent/<key>@<sourceOffset>`) are stable wire formats — changing them
// breaks dedup against events already committed to streams.
```

## Audit bug status (no code change needed)

- **2.4 zombie `pendingTriggerCount`** — fixed by construction since
#1460: the reconcilers guarantee dangling requests reach a terminal
event, and a queued count only ever represents real user inputs whose
follow-up turn rebuilds from full history.
- **2.3 cancellation check-then-act race** — still a theoretical window;
closing it needs conditional appends (append-if-still-current at the
stream layer), which is its own design, not a cleanup.

`pnpm typecheck && pnpm lint && pnpm format && pnpm test` all green.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Mostly UI deduplication and comment edits; Slack preset selection is
slightly broader if old auto-generated presets exist in storage, which
the PR assumes is empty.
> 
> **Overview**
> Introduces **`AgentSetupFormPage`** so **New Agent** and **New Agent
Preset** share one form (provider, model, run options, system prompt,
custom events YAML, live preview). Each route only keeps path handling,
its preview builder, and submit logic—roughly halving page size.
> 
> **Removes** the legacy **`isLegacyGeneratedSlackOpenAiPreset`** filter
and its test from `agent-presets.ts`. Slack agents still only match
Slack-scoped presets; stored `/agents/slack` presets are no longer
sniffed and ignored by prompt text.
> 
> **Trims** stale “migrated from `packages/shared`…” headers across
agent and Slack stream-processor modules, leaving short notes where wire
formats and idempotency keys must stay stable.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
c9cf738. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

<!-- CLOUDFLARE_PREVIEW -->
## Environment Config Lease
<!-- CLOUDFLARE_PREVIEW_STATE -->
<!--
{
  "apps": {
    "os": {
      "appDisplayName": "OS",
      "appSlug": "os",
      "status": "deployed",
      "updatedAt": "2026-06-10T22:24:45.981Z",
      "headSha": "c9cf738e2dad4877de8286cf370cf50cedd81eeb",
      "message": null,
      "publicUrl": "https://os.iterate-preview-4.com",
"runUrl": "https://github.com/iterate/iterate/actions/runs/27310094398",
      "shortSha": "c9cf738"
    }
  },
  "environmentConfigLease": {
    "dopplerConfig": "preview_4",
    "leasedUntil": 1781133683378,
    "leaseId": "51ccdfaf-05f8-4f1c-a8ed-1b26dec7500b",
    "slug": "preview-4",
    "type": "environment-config-lease"
  }
}
-->
<!-- /CLOUDFLARE_PREVIEW_STATE -->
Lease: `preview-4`
Doppler config: `preview_4`
Type: `environment-config-lease`
Leased until: 2026-06-10T23:21:23.378Z

### OS
Status: deployed
Commit: `c9cf738`
Preview: https://os.iterate-preview-4.com
[Workflow
run](https://github.com/iterate/iterate/actions/runs/27310094398)
Updated: 2026-06-10T22:24:45.981Z
<!-- /CLOUDFLARE_PREVIEW -->

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Post-merge grooming after the agents workstream landed (#1460, #1475,
#1483, #1484). Grooming rules (docs/tasks-grooming.md) say tasks are
deleted when done:

- **Deleted** `tasks/streams-core-processor-host-homogenization.md` —
the plan of record for what shipped in #1460.
- **Deleted** `tasks/agents-system-audit-and-reconciler-design.md` — the
audit knowledge dump; every verified bug and design direction in it is
now either shipped or carried by a live task file.
- **Updated** the two deferred follow-ups
(`streams-core-clock-durable-timers.md`,
`streams-event-kinds-metadata.md`) to drop their `dependsOn`/background
references to the deleted docs, pointing at the merged PRs instead.
- **Added** `tasks/streams-conditional-appends.md` — the one audit
finding that survived everything: the check-then-act window between a
provider's still-current check and its `agent/output-added` append.
Backlog, with the conditional-append direction written down so it isn't
lost with the audit doc.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Documentation-only changes under `tasks/` with no runtime or API
impact.
> 
> **Overview**
> **Grooms the `tasks/` backlog** after agents/streams work landed in
#1460 and related PRs, per `docs/tasks-grooming.md` (delete tasks when
done).
> 
> **Removes** the shipped plan-of-record
(`streams-core-processor-host-homogenization.md`) and the umbrella
audit/knowledge dump (`agents-system-audit-and-reconciler-design.md`),
since their content is either merged or split elsewhere.
> 
> **Refreshes** deferred follow-ups:
`streams-core-clock-durable-timers.md` and
`streams-event-kinds-metadata.md` drop `dependsOn` on deleted tasks and
cite PR #1460 in background instead of dead links.
> 
> **Adds** `streams-conditional-appends.md` (backlog) to capture the
remaining audit item—the LLM output **check-then-act** race—and the
direction (stream-level conditional append / CAS), so it isn’t lost with
the audit doc.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
d9b9d7f. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>