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interface AgentServerAdapterTransportAdapterPublic v1 name for TransportAdapter plus optional high-level
capabilities. Renamed to reflect that this interface now denotes the
full agent-server protocol contract (not merely wire transport):
any object that satisfies it can back a useStream call. See
plan-custom-transport.md §4 for the rollout.
The extra optional methods let adapters surface thread state and
history without the framework needing to issue a parallel HTTP
request — useStream.hydrate() calls getState?() when present
and falls back to client.threads.getState otherwise. Adapters
that don't know how to produce these values can simply omit them.
The legacy TransportAdapter export is retained for back-compat and
resolves to the same structural type; new code should prefer
AgentServerAdapter.
Thread ID this transport currently targets.
Shuts down the transport and releases any underlying resources.
Streams incoming protocol messages from the remote peer. Used by WebSocket transports where all events share one connection.
Fetch a slice of checkpoint history for the bound thread. Used by branching and time-travel UIs. Optional — omitting it turns those UIs into no-ops rather than surfacing an error.
Fetch the latest checkpointed state for the bound thread via
GET /threads/:threadId/state (or an adapter-specific override).
When omitted, StreamController.hydrate falls back to
client.threads.getState().
Opens the underlying connection (e.g. WebSocket handshake). For HTTP/SSE transports this is a no-op.
Opens an independent filtered SSE event stream.
Each call creates a new server connection with the given filter.
Returns undefined when the transport does not support per-subscription
streams (e.g. WebSocket), in which case the caller should fall back to
command-based subscriptions over events.
Replay contract. Implementations MUST buffer events emitted for
the thread/run and replay them through every newly-opened stream
whose filter matches. The SDK's shared-stream rotation relies on
this: when a subscription's filter widens the union, the SDK opens
a fresh stream and expects to receive the run's full history from
seq=0 (deduplication is handled client-side via event_id). The
SDK also defers the open until after run.start has committed the
thread server-side to avoid a 404: Thread not found, which means
events emitted during that window MUST be delivered to the late
opener. The protocol v2 server implements this via a bounded
per-run replay buffer; custom adapters should mirror that.
Sends a command and optionally returns an immediate response.
Rebind this transport to a different thread.
client.threads.stream(threadId, { transport }) calls this (when
implemented) whenever the framework binds or re-binds the active
thread — including the lazily-minted id from the first submit() on
a threadId: null controller. Implementing it lets an adapter be
constructed once (optionally with no threadId) and reused as the
active thread becomes known, so the framework doesn't have to tear
down and rebuild a custom transport when the thread id appears.
Optional: adapters that bake threadId at construction can omit it,
in which case the per-call threadId is ignored (prior behaviour).