cloudflare/agents agents@0.17.0 on GitHub

Minor Changes

#1758 6b46b04 Thanks @threepointone! - Add progress signalling and durable milestones for agent-tool sub-agents
(#1758, rfc-detached-agent-tools §progress, phases 4a + 4b).
A sub-agent running as an agent tool (awaited or detached/background) can now
report mid-run progress:
```
// Inside the child sub-agent (e.g. from a tool's execute):
await this.reportProgress({
  fraction: 0.6,
  phase: "deploying",
  message: "Generating menu page…",
});
```
These signals ride the child's own turn stream as a transient
data-agent-progress part, so they re-broadcast to the parent's connected
clients and surface on AgentToolRunState.progress via useAgentToolEvents — a
background-runs tray can render a live bar / phase / status line without drilling
in. Highlights:
- reportProgress({ fraction?, message?, phase?, data? }, { persist? }) on
  chat agents (@cloudflare/think, AIChatAgent); a no-op with a dev warning on
  the base Agent and when called outside an active agent-tool run. The framework
  resolves the run id from the active turn — no threading required. Bursts are
  coalesced (latest-wins; a fraction >= 1 "done" frame always flushes). data
  is live-only unless { persist: true }.
- onProgress(run, progress) parent hook, fired best-effort from the tail
  for both awaited and detached runs.
- Latest-snapshot persistence + recovery inspect. The child stores a
  progress_json + last_signal_at on its run row and surfaces it through
  inspectAgentToolRun().progress, so a rehydrated parent reconstructs progress
  after eviction.
- Resetting no-progress budget for detached runs. Once a detached child has
  reported at least one signal, the backbone gives up if it then goes silent for
  detachedNoProgressBudgetMs (default 1h; per-run override via
  detached: { noProgressBudgetMs }), surfaced as interrupted with the
  no-progress reason. A child that never reports is bounded only by the absolute
  detachedMaxBudgetMs ceiling — we never give up on a run merely for being slow.
Durable milestones (phase 4b)

Naming a milestone promotes a signal from the ephemeral tier to a durable
one — there is still only one emit method:
```
// Inside the child sub-agent:
await this.reportProgress({
  milestone: "sources-gathered",
  data: { sources: 2 },
});
```
- Persisted + replayable. Each milestone is one row on the child
  (cf_agent_tool_milestones / cf_ai_chat_agent_tool_milestones) with a
  monotonic per-run sequence. It rides the stream as a persisted
  data-agent-milestone part (vs. transient progress), so drill-in replay and a
  rehydrated parent both see it. Surfaced via inspectAgentToolRun().milestones
  and AgentToolRunState.milestones (deduped by sequence).
- onProgress fires for milestones too — the snapshot carries
  progress.milestone, so a consumer can branch on milestone vs. ephemeral.
- detached: { onMilestones } chat convenience (@cloudflare/think and
  AIChatAgent). When a configured milestone lands, the chat agent surfaces an
  idempotent synthetic chat message (keyed/idempotent per (runId, name))
  before the run finishes. Delivered from both the warm tail and the cold
  backbone reconcile; the deterministic id collapses them to at-most-once. Two
  modes (the string[] shorthand defaults to "narrate"):
  - "narrate" (default) — a synthetic assistant message injected directly
    (no inference): a cheap, honest status line that does not trigger a turn.
  - "react" — a user-role turn so the model responds to the milestone
    (steer, start dependent work). Costs a model turn.
```
detached: { onMilestones: ["preview-ready"] } // narrate (default)
detached: { onMilestones: { names: ["needs-approval"], mode: "react" } }
```
  Override the wording via formatDetachedMilestone(run, milestone). These
  synthetic messages carry metadata.source so clients can render them as an
  agent event rather than a human turn (the example does this).
The awaitable join point (awaitAgentToolMilestone, phase 4c) is intentionally
not included here — it is gated behind a design addendum.
#1790 190ea81 Thanks @threepointone! - Add typed action ledger observability events to the diagnostics channel event union.
#1790 190ea81 Thanks @threepointone! - Add typed action:pause:* (created/approved/rejected/swept) observability events to the diagnostics channel event union for durable-pause action approvals.
#1790 190ea81 Thanks @threepointone! - Add the ReplyAttachment type and an optional attachments field on ChatResponseResult, plus an action:reply-attached diagnostics event, to support the Think actions reply-attachment side-channel.
#1799 3c2afc9 Thanks @threepointone! - Stop reconnecting on terminal WebSocket close events and expose terminal connection failures via connectionError / onConnectionError on AgentClient, useAgent, and useAgentChat.
#1758 6b46b04 Thanks @threepointone! - Add first-class detached ("background") agent-tool runs with a durable
completion hook (#1752).
runAgentTool(cls, { detached }) now dispatches a sub-agent without blocking
the calling turn, returning a { runId, agentType, status: "running" } handle
immediately:
```
// Fire-and-forget — observe via agent-tool-event frames + onAgentToolFinish.
const { runId } = await this.runAgentTool(ImportAgent, {
  input,
  detached: true
});

// Or wire a durable, eviction-surviving completion callback (by METHOD NAME,
// like schedule()):
await this.runAgentTool(ImportAgent, {
  input,
  detached: { onFinish: "onImportDone", maxBudgetMs: 60 * 60 * 1000 }
});

async onImportDone(run: AgentToolRunInfo, result: AgentToolLifecycleResult) {
  // Branch on result.status: "completed" | "error" | "aborted" | "interrupted".
  // A budget give-up arrives as interrupted / reason "budget-exceeded".
}
```
Highlights:
- Durable, exactly-once-on-the-happy-path completion. A warm fast path
  (low-latency while the isolate is alive) plus a self-scheduling reconcile
  backbone (survives eviction / deploys) route through one guarded delivery
  funnel. Two independent ledger slots (finish / give-up) with a claim+lease
  mean a premature give-up can never dedupe a child's real late completion away.
- No silent abandonment. Detached runs are never sealed interrupted just
  because their dispatching turn ended (the normal state for a background run);
  the backbone owns them and re-arms on restart.
- Bounded. An absolute maxBudgetMs ceiling (default 24h, configurable via
  the detachedMaxBudgetMs static option) gives up — surfaced as interrupted
  with the new budget-exceeded reason — and tears the child down so an
  abandoned run cannot hold a concurrency slot forever.
- cancelAgentTool(runId) cancels a detached (or awaited) run by id through
  the same guarded path, so a wired onFinish still fires once with
  status: "aborted", and the terminal agent-tool-event is always broadcast
  to connected clients (a cancelled run's UI settles immediately).
- Recovery-safe delivery. A chat host (@cloudflare/think / AIChatAgent)
  runs the completion callback serialized on its turn queue, so an onFinish
  that mutates chat state can never interleave with a live LLM turn. Concurrent
  detached dispatches in one turn no longer race to arm multiple reconcile
  backbones (arming is serialized).
- Observability. New events agent_tool:detached:delivery_failed (a wired
  callback threw; the slot stays open for retry) and
  agent_tool:detached:live_count_warning (edge-triggered when live detached
  runs cross a threshold — a leak smoke alarm, since detached runs hold a
  concurrency slot for their whole life).
A detached run deliberately does NOT inherit options.signal (it must outlive
the spawning turn); cancel it explicitly with cancelAgentTool.
#1801 c58b401 Thanks @threepointone! - Add the shared agents/chat/react entry with useAgentChat, chat transport helpers, and shared chat wire types. The hook also adds syncMessagesToServer so hosts with server-authoritative transcript storage can keep setMessages local-only.

Patch Changes

#1790 190ea81 Thanks @threepointone! - De-duplicate three adapter-spine helpers shared by @cloudflare/ai-chat and
@cloudflare/think into agents/chat.
Three fragments that were duplicated byte-for-byte across both hosts now live
once as shared, @internal primitives:
- async-helpers.ts — the TIMED_OUT sentinel, awaitWithDeadline (a
  deadline-bounded promise race that always clears its timer), and
  drainInteractionApplies (the substrate-free interaction-apply completeness
  drain, parameterized by hasPending / getTail).
- classifyAgentToolChildRecovery(storage) (in recovery-incident.ts) — the
  parent's agent-tool reattach incident scan, with in-progress > failed > none
  precedence so a parent never gives up on a still-recovering child.
- interceptAgentToolBroadcast(msg, hooks) (in agent-tools.ts) — the #1575
  outgoing-frame snoop that forwards an agent-tool child's streamed progress to
  its live tailers (or captures its error), parameterized by an
  AgentToolBroadcastHooks substrate (the per-run forwarder / live-sequence /
  last-error maps, the host's response-frame type, and the host run-lookup).
Both hosts delegate through their existing private method names and
broadcast() overrides (which still call super.broadcast), so every call site
is untouched. This is a pure internal de-duplication with no observable behavior
or API change: the new symbols are @internal sibling-package support, not
public API, and both hosts' existing test suites pass unchanged.
@cloudflare/ai-chat and @cloudflare/think need no changeset for this
extraction.
#1790 190ea81 Thanks @threepointone! - Add the action:ledger:reclaimed diagnostics event to AgentObservabilityEvent, emitted when a stale pending action ledger row is reclaimed and re-run under the Think pending-retry lease.
#1790 190ea81 Thanks @threepointone! - Add channel:resolved, channel:delivered, notice:delivered, and notice:failed observability events to AgentObservabilityEvent for the Think channels surface. These route to a dedicated agents:channel diagnostics channel and are reachable via the typed subscribe("channel", cb) API (new ChannelEventMap bucket) rather than falling through to the catch-all lifecycle channel.
#1796 058a781 Thanks @mattzcarey! - Make the ai peer optional again. The root agents runtime and declaration graph no longer reference AI SDK types; AI-specific entry points still require the peer when imported.
#1802 391b034 Thanks @threepointone! - Ensure tool approval updates always retain a provider-facing approval id.
Older or hand-seeded transcripts can contain an approval-requested tool part
without an approval.id. When that part is approved and auto-continuation
re-enters inference, the AI SDK requires a matching approval id in the converted
model messages. Approval updates now synthesize a stable id from the
toolCallId when the transcript is missing one, preventing invalid prompt
errors while preserving existing approval metadata. @cloudflare/ai-chat now
routes its approval merge through the shared toolApprovalUpdate builder so it
benefits from the same fallback instead of its own divergent copy.
#1790 190ea81 Thanks @threepointone! - Extract the shared auto-continuation barrier into an AutoContinuationController
primitive in agents/chat.
The event-driven auto-continuation barrier (the tool-result → auto-continue flow,
#1649 / #1650) was duplicated, line-for-line, across @cloudflare/ai-chat
(AIChatAgent) and @cloudflare/think (Think) — the coalesce timer, the
double-fire guard, the create/update/defer scheduling branch, and the
completeness-gated drain orchestration. It now lives once as
AutoContinuationController, parameterized over a small AutoContinuationHost
interface (the stream-active signal, the incomplete-batch / pending-interaction
predicates, the apply-drain primitive, and each host's continuation-turn
pipeline). Both hosts delegate to it through thin wrappers, so every call site is
untouched.
This is a pure internal de-duplication with no observable behavior or API change:
the new symbols are @internal sibling-package support, not public API, and both
hosts' existing test suites pass unchanged. @cloudflare/ai-chat and
@cloudflare/think need no changeset for this extraction.
#1805 60e53e0 Thanks @threepointone! - Fix useAgentChat reordering a terminal/authoritative CF_AGENT_CHAT_MESSAGES snapshot when a protected streaming assistant is followed by a later assistant message (#1778). The protected-tail merge is still applied for stale mid-stream snapshots, but when the incoming snapshot already contains the protected assistant followed by a newer assistant (e.g. a Think HITL denial that persists the denied tool message and then appends a follow-up assistant response), protection is cleared and the snapshot is rendered in its authoritative order instead of moving the protected assistant to the end.
#1788 3b2af54 Thanks @threepointone! - Converge recovery forward-progress crediting between AIChatAgent and Think.
Both hosts now credit the recovery no-progress counter through one shared, host-agnostic rule (shouldCreditStreamProgress): a progress milestone (a started text/reasoning segment or a settled tool input/output) credits unconditionally, and mid-segment streaming deltas (text-delta/reasoning-delta/tool-input-delta) credit at most once per throttle window via a per-isolate StreamProgressCreditThrottle. Previously AIChatAgent credited only on chunk-type milestones while Think credited on its flush cadence, so a long single content segment spanning repeated crashes could read as "no progress" under AIChatAgent and false-fire its no_progress_timeout. The new rule is never coarser than either host's prior cadence, so it can only delay or avoid a false no-progress timeout, never hasten give-up.
#1430 d1c4342 Thanks @threepointone! - Support starting Agent workflows from sub-agent facets by preserving the originating facet path for callbacks and workflow Agent RPC.
- Route workflow callbacks, this.agent RPC, progress/completion/error, durable events, and state updates back to the exact originating facet via path-based dispatch.
- Match real Durable Object stub RPC semantics in path dispatch: reject built-in/prototype and JS-internal method names.
- Validate the workflow origin payload version so a mismatched SDK fails with a clear error instead of misreading the shape.
- Document the callback routing constraints (name-based resolution, sub-agent workflow tracking is facet-local, class names must survive bundling).
#1818 fa7bfec Thanks @threepointone! - Stop a tool-output-denied chunk from clobbering a settled or user-approved
tool part in agents/chat.
applyChunkToParts now treats tool-output-denied as first-write-wins: it
leaves a part already in output-available / output-error / output-denied
untouched, and — importantly — no longer flips an approval-responded
(user-approved) part to output-denied. An auto-continuation that re-validates
the transcript can legitimately emit tool-output-denied for an approval the
AI SDK deems unneeded (e.g. a tool without needsApproval); previously that
silently turned a granted approval into a denial in the persisted message. This
matches the first-write-wins guards already on the tool-input-* handlers and
benefits both @cloudflare/ai-chat and @cloudflare/think.
isReplayChunk now recognizes the same replayed tool-output-denied (for a
part already settled or in approval-responded). The server-side guard only
protects the persisted message; without this, the stale denial chunk was still
stored in the resumable-stream buffer and broadcast to connected clients, where
AI SDK v6's in-place updateToolPart would regress the rendered tool part back
to output-denied (and replay it on reconnect). Filtering it at the broadcast
boundary keeps the client UI consistent with the persisted state.
tool-approval-request gains the same treatment on both paths: a
first-write-wins guard in applyChunkToParts (so a replayed approval request
can't regress an already-approval-responded or settled part back to
approval-requested, discarding the user's decision) and a matching
isReplayChunk branch (so the replayed request isn't stored or broadcast,
which would otherwise revert an approved tool to re-showing Approve/Reject on
the client and on reconnect).
#1734 cd2c430 Thanks @whoiskatrin! - Allow McpAgent server-to-client requests to send from callbacks that do not inherit the agent's async context, including callbacks reached through Worker Loader RPC.
#1794 b6ad4d5 Thanks @threepointone! - De-duplicate the orphan-persist core shared by @cloudflare/ai-chat and
@cloudflare/think into agents/chat.
The genuinely-common skeleton of both hosts' _persistOrphanedStream — the
accumulate loop plus the getMessage → updateMessage(merge) XOR appendMessage
upsert — now lives once as the @internal persistReconstructedOrphan helper.
The deliberately host-specific bits stay in the callers: the buffer flush, the
fallback id, the prepare hook (Think strips internal parts and may skip;
ai-chat resolves the persist-target id), the merge hook (Think replaces;
ai-chat reconciles partials), and broadcast (Think after; ai-chat inside its
store's persistMessages).
Pure internal de-duplication with no observable behavior or API change: the new
symbol is @internal sibling-package support, not public API, and both hosts'
recovery suites pass unchanged. @cloudflare/ai-chat and @cloudflare/think
need no changeset for this extraction.
#1788 3b2af54 Thanks @threepointone! - Export reconcileOrphanPartial from agents/chat.
This is the shared primitive that merges a freshly-reconstructed orphaned stream
partial onto an assistant message that already owns its target id (an early
persist at tool-approval time, or a continuation resuming the prior assistant
message). It keeps all existing parts, appends only reconstructed parts whose
toolCallId is not already present (so a recovery replay never duplicates a
tool call), and overlays incoming metadata onto existing — preserving an
in-place tool result that lives only in storage rather than letting a replayed
chunk re-advance it. @cloudflare/ai-chat's orphan-persist path now uses it;
hosts whose orphan persist only runs at stream finalize don't need it (the
shared reconstruction is already idempotent by toolCallId).
Additive export only — no behavior change to existing APIs.
#1788 3b2af54 Thanks @threepointone! - Export the OrphanPersistStore<M = UIMessage> type from agents/chat.
This is the minimal message store the chat-recovery orphan-persist write goes
through — the write subset of SessionProvider (the getMessage,
appendMessage, and updateMessage methods). It is parameterized over the
host's message type so the seam itself is not AI-SDK-specific: the AI-SDK chat
hosts (@cloudflare/ai-chat, @cloudflare/think) instantiate it at the
UIMessage default, while SessionProvider satisfies it at its own
SessionMessage. Both hosts now route their orphan-persist write through a host
adapter typed against this interface, turning the previous by-convention
alignment into a type-enforced contract.
Additive export only — no behavior change to existing APIs.
#1803 c476265 Thanks @threepointone! - Fix AI SDK status getting stuck after a reconnect that races a turn's
pre-stream window (#1784).
A turn is "accepted but pre-stream" while it is queued, debouncing, or awaiting
async setup before its resumable stream starts. A client that connected or sent
a STREAM_RESUME_REQUEST in that window was answered with STREAM_RESUME_NONE
("nothing to resume"), so its short resume probe resolved null and AI SDK
status settled on ready even though the server went on to stream — leaving
the UI unable to render the in-flight turn until a full remount.
This adds a shared PreStreamTurns tracker (agents/chat) and a new
server→client cf_agent_stream_pending frame:
- The resume handshake now parks resume requests that arrive during the
  pre-stream window and emits STREAM_PENDING ("keep waiting") instead of
  STREAM_RESUME_NONE, then flushes parked connections into the normal
  STREAM_RESUMING handshake once the stream actually starts (and releases them
  with STREAM_RESUME_NONE if the turn is superseded/cleared before streaming).
- On STREAM_PENDING the client transport extends its resume probe from the
  5s fast-path to a 60s backstop so the probe stays open across the gap.
- useAgentChat re-probes the stream on a transparent socket reopen (e.g. a
  1006 reconnect that does not remount the component) so status recovers.
- Continuation affinity is relaxed via an optional isConnectionPresent host
  hook so a transparent reconnect (whose connection id changed) can resume a
  continuation whose original owner connection is gone.
Wired into both AIChatAgent and @cloudflare/think.
The pre-stream tracker is in-memory only; it is hibernation-safe because a turn
in its pre-stream window is an unresolved message-handler promise that pins the
Durable Object in memory, so eviction only happens once a stream is durably
recorded (and resumes via ResumableStream) or the turn has finished. Skipped
turns (supersede/generation change) settle without releasing parked
connections, so a client parked during the window survives onto the successor
turn instead of being cut loose by a premature STREAM_RESUME_NONE.
#1794 b6ad4d5 Thanks @threepointone! - Extract transcript repair into a shared agents/chat primitive.
@cloudflare/think's _repairToolTranscriptParts — which flips an interrupted
tool call (a tool-* / dynamic-tool part with no settled result, left behind
when a stream was cut off mid-flight) into an errored tool-result so the next
provider call doesn't 400 with AI_MissingToolResultsError, and normalizes
malformed tool input — now lives once as the shared, @internal
repairInterruptedToolParts primitive (plus the toolPartHasSettledResult
terminal-state check) in agents/chat.
The primitive is pure (returns a new messages array plus repair stats; never
touches storage, broadcast, or events) and is parameterized by an overridable
repairPart hook plus an optional shouldRepair(part) skip predicate (defaults
to repairing every interrupted part), so both AI-SDK chat hosts can run repair
logic before re-entering inference on a recovered turn — a host whose default
errors the part (ai-chat) uses shouldRepair to leave a part still awaiting a
client interaction verbatim. @cloudflare/think delegates through its existing
repairInterruptedToolPart hook with no shouldRepair (repairs everything) — a
pure internal refactor with no observable behavior or API change; its suites pass
unchanged.
#1772 d4f27fe Thanks @mattzcarey! - Include each package's documentation in its published package.
#1815 b20d6f6 Thanks @threepointone! - Move just-bash from a runtime dependency to an optional peer dependency so apps only install it when they use the skills bash runner.
#1790 190ea81 Thanks @threepointone! - Add stable approval descriptors for Think actions and preserve approval descriptor metadata on chat tool parts.
#1790 190ea81 Thanks @threepointone! - Add chat:turn:start and chat:turn:finish observability events for Think
turn execution.

cloudflare/agents agents@0.17.0 on GitHub

Minor Changes

Durable milestones (phase 4b)

Patch Changes

cloudflare/agents agents@0.17.0
on GitHub