mobkit_gateway and the SDK-facing
rpc_gateway, bind 127.0.0.1 on an ephemeral port unless the launch selects
another address. This page explains the posture, the three shipped ways to
publish a gateway, and the exposure gate a non-loopback bind has to pass.
Why loopback is the default
Everything a gateway serves over HTTP hangs off one listener: the bundled console, console JSON-RPC, blobs, SSE event streams, and (when enabled) the live WebSocket transport.mobkit_gateway serves its protected console
surfaces open by default when top-level auth_config is absent. Supplying
that init parameter installs the shared JWT/OIDC configuration and requires
app auth on those surfaces. rpc_gateway is fail-closed by default: it trusts
no signing key and refuses protected console requests until the host passes
runtime_options.auth_config or explicitly opts out with
runtime_options.console_require_app_auth = false. Without gateway auth,
loopback or an authenticating front proxy must provide the access boundary.
See Authentication for the shared auth shape.
Loopback is therefore a security posture, not an oversight. The SDK process that
spawns a gateway shares its network namespace and reads the exact
http_base_url from the mobkit/init result, so nothing on the host needs a
fixed or public port.
Publishing a gateway
Same host or same network namespace: proxy to http_base_url
The pattern the shipped hosts use. The SDK runtime exposes the base URL after
connect() (runtime.rust_http_base_url in Python, runtime.rustHttpBaseUrl
in TypeScript); the host’s own web server proxies /console and the routes it
wants to publish to that base and authenticates in front. Works for a process
on the same machine, a Kubernetes sidecar in the same pod, or a Docker
container started with --network container:<gateway>. The port is ephemeral,
so read it at runtime rather than configuring it.
mobkit_gateway additionally records http_base_url in its runtime registry
under the gateway state directory, so a same-host proxy can discover a resumed
runtime without holding the init handshake.
Separate containers: bind a non-loopback address
A reverse proxy in another container on a bridge network cannot reach127.0.0.1 inside the gateway’s container. For that topology bind the listener
on the container’s interface and let the gate below decide whether the bind is
allowed:
- Python (rpc_gateway)
- TypeScript (rpc_gateway)
- mobkit_gateway
- Raw mobkit/init (rpc_gateway)
http_listen takes an IP literal and port (0.0.0.0:8080, [::]:8080,
192.168.0.10:8080); hostnames are refused so the bind cannot resolve
differently on the next host. HOST:0 still asks the kernel for a port.
The init result then carries two base URLs:
The public base is advertised, never bound: it is the operator’s statement of
how clients reach the proxy in front of the gateway. The Python runtime exposes
it as
rust_http_public_base_url (falling back to the same-host base when
none was declared) and TypeScript as rustHttpPublicBaseUrl.
Rust library host: serve the router on your own listener
UnifiedRuntime::run(listener, decisions, shutdown) and ::serve(listener, decisions) accept any TcpListener, and GatewayHttpBinding::bind(addr) is
the shared admission type the binaries use. examples/library_mode_reference.rs
(MOBKIT_REF_ADDR) is the template. A library host owns its own exposure
decision; run validate_http_bind_policy if you want the same gate.
The exposure gate: auth or acknowledgement
The shared gate refuses a non-loopbackhttp_listen at init, before any runtime
is bootstrapped, unless one of two things is true in its admission-time state:
- The console enforces app auth.
require_app_authis on AND the trusted JWKS carries at least one key, which is whatauth_config(Python.auth(...), TypeScript.auth(...)) produces. The listener then carries its own access boundary. Note that the fail-closed default,require_app_authwith an empty key set, does not count: refusing everyone protects the listener but authenticates nobody, and is not a deployment anyone intends. - The launch acknowledges the exposure with
allow_remote. This is the same word and the same rule as--allow-remoteonrkat-rpc --tcpandrkat mob host --listen-tcpin Meerkat: an explicit transport-exposure opt-in, not an auth mechanism. Pass it only when an authenticating proxy fronts the listener.
rpc_gateway applies its runtime_options.auth_config before this check.
mobkit_gateway accepts the same JWT/OIDC shape as top-level auth_config,
but its earlier exposure gate currently uses the open default decision state,
not the later auth overlay used by the HTTP router. On that binary a
non-loopback bind therefore still requires allow_remote (init param,
--allow-remote, or MOBKIT_HTTP_ALLOW_REMOTE=1), even when auth is configured.
On both binaries a refused bind answers mobkit/init with a -32602 error on
the request id whose message names the address and every way out.
The listener is bound right behind the gate, before any bootstrap. A fixed
http_listen port makes “address already in use” a realistic init failure,
and it is answered the same way: -32603 on the request id naming the
address, with nothing built behind it (no runtime, no session store, and no
schedule executor lease that a process exit would leave held for its full
duration).
At serving startup, every admitted non-loopback listener logs one WARN line on
stderr naming the bound address and the final serving auth posture. On
mobkit_gateway this includes any configured auth_config overlay, unlike the
open decision state used by its earlier exposure gate. It cannot be silenced
below WARN by the default filter.
Reading schedule watchdog diagnostics
Both gateways install a resident watchdog that probes every 60 seconds when persistent schedule-service inputs are available. Ephemeral launches and launches whose schedule store is unavailable do not install it. An immediate boot probe runs after the firing host successfully starts; if host startup fails, startup logs that failure and the resident watchdog still runs. Only Pending occurrences more than 120 seconds overdue under an authoritative Active parent contribute to a firing-pipeline stall, its count, and its oldest due time. A boot backlog logs WARN; a new or changed periodic stall logs ERROR, with a WARN heartbeat every ten unchanged polls. Paused and Deleted parents can retain Pending occurrences without a firing fault. The DEBUGschedule overdue pending parent attribution record reports
separate active, paused, deleted, and unresolved counts; the probe does
not modify those rows. Enable meerkat_mobkit::schedule_wiring=debug in
RUST_LOG to see these buckets.
Missing parent evidence or failed/poisoned reads log observation incomplete
at ERROR, including at boot, rather than claiming health or attributing a
stall to inactive work. A mixed report retains unresolved evidence alongside
any known active backlog. Executor owner and fencing-token observations explain
an active backlog only; they never grant firing authority.
Building with openai-live: link the system Opus
The openai-live feature pulls Meerkat’s WebRTC transport, whose opus
dependency builds bundled Opus with CMake when pkg-config finds no system
library. Install the system library in the build stage so the build links it
and never runs CMake (which also avoids the CMake 4 incompatibility of the
bundled sources):
OPUS_STATIC=1 in the build
stage alongside libopus-dev.
Docker sketch
http_base_url); only the proxy is
published. If the proxy instead shares the gateway’s network namespace, keep
the loopback default and proxy to http_base_url.
Resume behaviour (mobkit_gateway)
The HTTP listen address and the advertised http_public_base_url are both
part of the runtime resume fingerprint, like --control-listen. Relaunching
with a different http_listen or a different (or newly dropped)
http_public_base_url creates a runtime with the values you declared instead
of silently reporting a live runtime started with other ones; with a fixed
port that new runtime cannot bind while the old one still holds the port, and
init says so. A resumed launch (same fingerprint) reports the http_base_url
and http_public_base_url the live runtime was started with, which are by
construction the ones you declared.
Repairing a refused durable session
A member whose committed WholeBlob document fails meerkat’s audited-endpoint guard (SessionError::WholeBlobAuditedEndpointDivergence) is parked with a
typed session_repair_required hold instead of retrying: it shows as
needs_repair in the console and on mobkit/member_health, and the hold
carries the two exact rkat commands for the runtime store this gateway
opened. Both gateways derive that scope from their own storage composition,
never from a guess:
- the default persistent launch opens
<state_dir>/runtime.sqlite, so the commands arerkat session repair-wholeblob <session_id> --runtime-store <state_dir>/runtime.sqlite --json(diagnose) and the same with--apply --json(repair; add--accept-shorteronly when the diagnose report says the live transcript is shorter than the audited endpoint); - a composite storage provider’s meerkat-level realm renders as
rkat --state-root <state_dir> --realm mobkit session repair-wholeblob <session_id> ...; - an in-memory or declared-ephemeral runtime store has no document to repair,
so no scope is derived and the commands keep explicit
<state-root>/<realm>placeholders.
mobkit/reload_member on the identity; the same
verb, with no extra flag, resumes the same session and generation and clears
the hold.
Reading a gateway exit
Both gateways log on stderr, throughtracing, at the default filter (no
RUST_LOG needed). When the run loop ends, the binary writes one INFO line
naming which branch ended it, runs the graceful shutdown sequence, then writes
a closing bookend:
reason= is one of these tokens; signal= (SIGINT or SIGTERM) is present
only when the reason is signal.
mobkit_gateway does not exit on stdin EOF. It logs stdin closed by the launching process; mobkit_gateway keeps serving HTTP until SIGINT or SIGTERM
and stays up, so a later exit is attributed to what actually ended it. After a
signal it exits once shutdown completes whether or not stdin is still open (a
terminal, or a parent holding the pipe); both gateways exit explicitly on that
path because tokio’s stdin read cannot be cancelled.
Panics are reported through the same stream at ERROR, with thread, file,
line, column and payload fields, before the standard panic message
(RUST_BACKTRACE still works). A panic on a tokio worker unwinds one task and
the process keeps running, so this line may be the only record of one.
How to read a gateway that is gone:
- The “loop ended” line is present with
reason=signal: a supervisor or operator stopped it. Check who sent the signal (container stop, health check timing out during a long console operation,kill). reason=stdin_closedonrpc_gateway: the SDK host process exited or closed the pipe; look at the host first.- The “loop ended” line is present but the bookend is not: the shutdown sequence wedged or the process was killed during it.
- Neither line, but a
panicERROR: a crash; the line names the source location. - No line at all: the process was killed from outside (SIGKILL, an OOM kill,
a stack overflow) or aborted. The exit status names which;
137is SIGKILL,139is a segfault or stack overflow,134is an abort.
WorkGraph realms for mob members
Meerkat builds every mob member in the realmmob.<mob_id> and rescopes the
WorkGraph service the gateway hands the mob runtime to that realm, so a member
resolves its attention bindings there and nowhere else. The gateway’s own
WorkGraph service is scoped to the same realm at construction, which is why a
goal bound to a member from the console or the RPC surface lands where the
member reads it.
Two consequences matter to an operator:
- A goal, binding or reassignment whose target names a member of another mob
(an explicit
ownerkey of the formmob/<other>/agent/<identity>) is refused with JSON-RPC-32602anddata.kind = "attention_target_realm_mismatch". It is not stored anywhere. Create that work through the other mob’s own runtime. - Bindings written before this rule existed are moved at bootstrap. A child
mob spawned by an agent tool used to share the parent runtime’s service
unscoped, so a goal bound to a child-mob member lived in the parent realm
and the child member found it there; it no longer does. On every bootstrap
the runtime scans its realm for active or paused bindings whose owner key
names another mob, re-creates each in that mob’s realm over the same store
(title, description, mode, policies, priority, labels, timing fields,
external and evidence refs, delegated authority, projection policy and the
paused state carried; edges of the original item are not), and cancels the
original goal, which stops its binding. A second bootstrap finds nothing to
move.
mobkit/capabilitiesreports the run underworkgraph_realm_migration(mode,scanned_bindings,skipped_terminal,migrated[]with the old and new binding and item ids, and anoutcomethat records a failed scan or write instead of aborting the launch). Library hosts choose the mode withMobBootstrapSpec::with_workgraph_realm_migration(apply,dry_run,off).
Blob ids are not meerkat content blob ids
A MobKit blob store applies one of two digest recipes depending on how an object enters it. Images that arrive through meerkat’sBlobStore face
(Base64BlobStoreAdapter::put_image, used by the gateway, the unified runtime
and the console voice host) and images uploaded through the console
(mobkit/blob/upload, multipart image_upload placeholders) are addressed
with meerkat’s content_blob_id, sha256(canonical_media_type || 0x00 || base64_text) over the base64 form, so meerkat’s read-back verification
(durable fork preflight, realtime image hydration) accepts them. Objects
written through MobKit’s native BinaryBlobStore::put_bytes (non-image
mobkit/blob/* objects), and image blobs written by MobKit builds that
predate this rule, carry MobKit’s own address, sha256(media_type || 0x00 || raw_bytes) over the decoded bytes (meerkat-mobkit/src/blob_store.rs,
compute_blob_id). Both render as sha256:<64 hex digits>, so the same PNG
under the two recipes carries two visually indistinguishable ids. The store
resolves both forms through both faces, so references written before the rule
keep hydrating; still, compare ids only within one recipe. The side by side
recipe, provenance rules and the planned unification are documented in the
meerkat storage operations runbook under “Blob digests in meerkat and MobKit”.
See also
- Configuration: the
http_listen,http_public_base_urlandallow_remoterows - Authentication: configuring
auth_config - Console: the console surface these binds publish
- Unified runtime:
GatewayHttpBindingin a library host
