Skip to content

antst/sessionbus

v0.4.0

Generic Sessionbus guidance for managed Qwen launches and lanes. Ordinary Qwen discovers the skill without starting a Sessionbus MCP helper.

GitHub

Qwen Sessionbus package

One Go binary supplies qwen-peer and its private sibling alias qwen-peer-mcp. The native Qwen installation supplies its own Node runtime; this package adds no Node adapter or npm dependencies. Use the archive so the lane worker can resolve its exact private sibling executable.

scripts/package-product qwen ./dist
mkdir -p ./dist/qwen-install
tar -xzf ./dist/qwen-peer-linux-amd64.tar.gz -C ./dist/qwen-install
sh ./dist/qwen-install/install

Select the archive for the target platform. The literal installer replaces ~/.local/libexec/sessionbus/qwen, links ~/.local/bin/qwen-peer, and uses native qwen extensions uninstall/install for the owned sessionbus extension. Reinstall replaces the owned plugin payload, including removed skills. It preserves unrelated extensions and native history. The archive contains one generic skills/sessionbus/SKILL.md, covering every product through the same public tool; there are no separate product lane skills.

Current lane interface

The daemon starts the token-selected worker with no model input. It owns one native qwen --acp session and one shared Worker/Caller. Fresh Open adopts the native session/new ID. Resume uses the retained native ID and rejects a conflicting returned ID. The per-session MCP configuration uses the absolute private sibling executable and a unique endpoint for that native session. The helper forwards the single public tool to that existing Caller.

Call mcp__sessionbus__sessionbus with {action, arguments}. Qwen may defer the tool behind native tool_search; use select:mcp__sessionbus__sessionbus to discover it. Successful helper initialization proves helper startup only, not completed native tool discovery or permission to call a tool. Preserve native refusals; do not force a grant or change deferral to obtain success.

Use describe with product:"qwen-peer" for supported Open fields, and spawn with a product, child name and explicit open object. The current fields are cwd, permission_mode, model, reasoning_effort and arguments. Omitted/default permission uses native policy; bypassPermissions is an explicit caller choice. Model and supported effort values are passed through their native configuration paths. Unsupported values and arguments conflicting with owned lane controls are rejected. No default permission grant is added.

start returns session_id/run_id; run, status and wait read without consuming. Receive a done result or report an unavailable reason before ack; never acknowledge running. Interrupt acknowledgment is not a terminal result. The one shared run remains owned until its native prompt and admitted delivery and cancel operations settle. Closing or losing the worker invalidates its unacknowledged results. See the generic skill for the action examples, completion pointers and independent lifetime policies.

Idle stage retains only never-submitted messages in a bounded memory FIFO; queued_for_next_turn is not native admission. A seeded wake returns written after the full native prompt request write. Active delivery waits for native craft/drainMidTurnQueue and writes at most ten messages per response. Written does not mean injected or consumed. Native late recovery owns handed-off messages; the wrapper never replays them. An unsent message remains staged if the current run ends without a native pull.

Close and automatic close retire the lane and leave native Qwen history in place. Forget removes the daemon's resume recipe, not native history. There is no wrapper database, result journal or restart recovery. The shared result cursor and staging are bounded worker memory.

Interactive launches and ordinary Qwen

The installed extension contains one generic skill and no MCP registration. Ordinary native Qwen can discover the guidance but does not start this package's MCP helper. qwen-peer adds its private sibling through one per-launch native --mcp-config; dedicated ACP lanes use their per-session configuration instead. Existing settings and other extensions retain native precedence.

Native initial selectors (including bare/title/ID resume, continue and fork) remain native arguments. Native subcommands and help/version pass through. Repeated -g/--group comma lists and -n/--name/--peer-name are wrapper options before --; tokens after -- remain untouched. No generated native ID or title resolver is used. Explicit native permission arguments remain unchanged and omitted policy stays omitted. Headless input belongs in a lane. The wrapper reserves --input-file, --json-file and --json-fd, and requires native chat recording for titles.

A single caller --mcp-config is composed in its original position. Existing files use native file-only JSON comment handling; inline input is strict JSON. Wrapped mcpServers and direct maps retain raw server values, numeric tokens and unknown fields. Both caller input and combined output are capped at 65536 UTF-8 bytes. Duplicate flags, malformed input and an explicit caller sessionbus server fail clearly. Caller files are never edited. No second config flag, all-extension enablement, global toggle or permission grant is introduced.

After MCP initialization, the helper reserves an empty exclusive launch claim after native env and live launch-ancestry validation, then asynchronously matches the first native session_start, its native QWEN_CODE_SESSION_ID, and a live launch-owned native process/registry record. Registry publication is source-bound ordering after normal input-watcher construction; native caught watcher-init failures mean it is not universal watcher-health proof. Linux checks native process-start and PID-namespace tokens; macOS native records have null tokens, so live sysctl process identity and a registry timestamp after that process start qualify the weaker native record. Tools remain cancelable while binding is pending.

Native camel-case aliases of the managed input/output, recording and MCP-config options have the same reserved/composition rules as their dashed spellings. Recording-disable aliases are rejected; caller configuration is still composed into one argument at its original position.

Initial -n uses literal /rename -- <name> so flag-like names cannot select auto-rename. Names use native whitespace normalization (runs become one space) and the native 200 UTF-16-code-unit limit; empty, multiline, invalid UTF-8 and NUL-containing names are rejected before launch. The rename is appended once after that gate, then published only after matching native custom_title confirmation. Existing historical title text cannot confirm this new rename. Later native title changes, including clearing a name, update the same bus connection. An empty per-launch exclusive claim prevents restarted or overlapping helpers from creating another owner or repeating the rename; a failed owner requires a fresh launch. This includes a native updater that restarts Qwen within the same launcher: exit that replacement and start a new qwen-peer process. Integration is not transferred to the replacement helper. The claim contains no session metadata.

Initial daemon absence and later daemon connection loss keep the same helper and native session alive. The helper retries the launch's socket and publishes the current session name after reconnecting. Calls during an outage return not_connected; old calls and deliveries are never replayed. A rename on an already admitted connection keeps delivery admission while its updated hello is pending. Supersession, a refused hello, and native/helper exit remain terminal; they do not start another owner. Lane Workers retain their single connection lifetime.

The launcher owns its native child, unique temporary input file and native event FIFO until native exit. One claimed helper reads the initial native event and then drains/discards output; it does not store an answer transcript. Native may open before or after the reader. The reader closes and joins on cancellation. The input file remains append-only during the live launch, with an 8 MiB per-record wrapper limit and no total-byte ceiling; it is never truncated or rotated because native consumed-offset guarantees are absent. Native event and history observation records are bounded at 8 MiB. Directory/file watches are bounded at eight, and incoming bus handler work at 32. This is temporary native transport, not a wrapper history/recovery store.

Terminal-group SIGINT is left to native Qwen; the launcher does not convert it into TERM or send a duplicate interrupt. Normal exit/TERM joins the child and removes those resources. Helper EOF, native-parent loss or launcher loss cancels its sole Caller and observers. If the launcher is killed abruptly, the integration retires but native processes and unique files may remain; there is no claim of reaping/cleanup by a dead launcher and no recovery from these files.

Session switching limitation

The owner has accepted the released native interfaces' session-switch limit: Sessionbus binds to the launch's initial native session. After an in-process /new, /clear, /resume or other switch, outbound MCP calls can retain that old identity while input-file deliveries reach the displayed session. Presence, delivery and completion-pointer attribution across that switch are outside supported guarantees. Exit and start a fresh qwen-peer using the native selector to use Sessionbus with another session. This is guidance, not an enforced switch ban or a race-free withdrawal mechanism. ACP lanes each own a dedicated session and are unaffected. No native patch is a prerequisite.

The lane runtime was exercised on unmodified Qwen 0.23.0: new/resume startup, native ToolSearch plus public list, staged delivery, seeded wake, active pull, interrupt, repeated collection/acknowledgment and healthy following runs. Receipt limits and later process-absence evidence are retained separately; these observations are not an interactive or all-policy acceptance claim. The same permanent installation now has native interactive identity/name/groups, public ToolSearch/list, parent/child completion-pointer collection, inbound observation, fresh-process title resume and ordinary skill-only checks. Native 0.23.0 executed the model rows; native auto-update moved later zero-model resume/ordinary/lifetime checks to 0.23.2. See the acceptance ledger for exact evidence and limits, including updater relaunch and abrupt cleanup.