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Incident record 2026-11-04: afternoon responsiveness loss — sandbox wedged after post-boot herd (daemon restart, 88-min sampler silence); laptop path exonerated 21:00–21:28 UTC #5701

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Description

@dezren39

Incident record — 2026-11-04 afternoon responsiveness loss (sandbox ↔ laptop path)

Drew's chat went unresponsive shortly after 15:00 CST ("connection error / reconnecting" at ~16:09, last activity ~15:0x). Two orchestration passes failed (14:12 no execution; 15:12 timeout after prelude). An independent workstream (Mistral-provider build, chat f3937a75) reported the fleet session proxy "closing EVERY CONNECT to the laptop (laptop-agent: proxy closed during CONNECT — three consecutive failures after earlier intermittent ones)". Drew powered the laptop OFF at ~17:01 CST and responsiveness returned — but the sandbox also recycled at 16:57 CST, which is the more mechanical explanation for the recovery (a fresh boot clears the wedged state, whatever it was).

Timeline (UTC; CST = UTC−6)

  • 14:38–20:57 — boots 0a18fb7e, da56f9ed (16:20), ad076b64 (18:27), d50de26a (20:57). Baseline load already high: resource sampler shows load 11–13 on 4 CPUs at 00:0x, and .rustdesk-wrapper ~45% CPU through the ad076b64 evening.
  • ~20:43–21:16 — the repo-queue → fleet-queue migration completed (29 cron jobs) and the exceptions coordinator finished; heavy parallel agent work in flight (Atlas revision, Mistral build, ID sessions).
  • 21:00–21:28 (boot d50de26a) — client trip log: 280 laptop-agent trips, ALL status 200, 10–19/min, 15 slow (>5 s, worst 217 s — a long exec that completed). The laptop path itself was working. Load 2–8, mem avail 1.0–4.4 GB. Init re-running every 2–7 min in the background (see the init-loop issue — fixed separately).
  • 21:22:46 — sandbox recycled again (boot 3ed35cc9, only 25 min after d50de26a).
  • 21:25–21:29 — post-boot thundering herd: sampler shows load climbing; at 21:29:17 load 30.39 (1-min) / 12.61 (5-min), a .gh-wrapped process tree at 1645% CPU, and the Muse daemon restarted (pid 67 → 10918).
  • 21:29:17 → 22:57 — the resource sampler produced NO further lines (it had sampled every 2 min all day). Sandbox-side agent trips also essentially cease (2 trips in ~90 min vs ~280 in the prior 28 min). This ~88-minute window is Drew's dead period.
  • 22:57:31 — sandbox recycled (boot 6989413c). Sampler, daemon, and trips resume immediately. Drew's connectivity returns ~17:01 CST (23:01 UTC) — in the new boot.
  • After 23:01 — trips fail with ~25–32 s timeouts and status: null because the LAPTOP IS OFF (Drew powered it down) — expected, not a fault.

What the evidence establishes

  1. The laptop and the laptop-agent path were not the failure in the 21:00–21:28 window: 280/280 trips succeeded. The failure begins with a sandbox recycle (21:22) and a post-boot load explosion (21:29).
  2. The sandbox side wedged, not the transport: a daemon restart + a sampler that stopped sampling for 88 minutes + agent traffic ceasing all point at the sandbox VM/daemon being frozen or CPU-starved, not at CONNECT refusals. (The Mistral agent's "proxy closed during CONNECT" errors are consistent with a sandbox-side proxy process starved/frozen mid-handshake — the broker log also holds a ConnectionRefusedError from tunnel_socket to the runtime proxy port and repeated client BrokenPipes — but the broker log has no timestamps, so those cannot be placed in the window. That is a logging gap to fix.)
  3. Recycle cadence is part of the story: six boots on 2026-11-04 (02:25, 04:18, 06:03, 10:34, 12:33, 14:38, 16:20, 18:27, 20:57, 21:22, 22:57 — the sampler's boot list is even longer). Every recycle triggers catch-up cron firings + full init + the platform's apt replay; the 21:22 boot's herd is the one that tipped over.
  4. The fleet-queue migration is not implicated by any direct evidence: migrated jobs invoke fleet queue on the sandbox, which reaches the queue-broker on the laptop through the same proxy pools as before; trip-log volume in the healthy window is agent execs (unchanged path), and no queue-connection errors appear in any timestamped log. The migration coincided with the incident window but the failure signature (daemon restart, sampler death) is sandbox CPU/life-cycle, not queue-client behavior. Remaining unknown: the Rust client's per-call connection behavior (pool reuse vs new CONNECT per call) — source is in the code repo (laptop, off at filing time); verify when it returns.
  5. Contributors, honestly weighted: (a) post-boot thundering herd (catch-up crons + lanes + coordinators + platform apt replay) — strongest fit for the 21:29 spike; (b) the init re-run loop (fixed separately) added a ~65 s job every few minutes all day; (c) standing oversubscription — load 11–13 at idle-ish times on a 4-CPU box, .rustdesk-wrapper ~45% for hours; (d) a .gh-wrapped burst at 1645% at the spike moment (many agents shelling to gh simultaneously after the boot).

What is NOT established (and the tests that settle it)

  • Concurrent-connection ceiling: Drew's proposed clean ramp test (50 → 64 → 128 concurrent proxied connections sending real messages, find where errors start) has NOT been run — it needs the laptop ON (every proxied target terminates there). Run it when the laptop returns, against the queue-broker port and the daemon port, and record where "proxy closed during CONNECT" first appears, if anywhere.
  • Why the sampler stopped: service death vs whole-VM freeze cannot be distinguished from surviving logs (the sampler's own log IS the missing data). sysstat collection (added 2026-11-04) would have answered this; ironically its install was blocked all day by the init-loop bug (now fixed), so the next incident should have sadc data.
  • Laptop-side state in the window (broker/daemon logs, laptop load): pending — laptop is off by Drew's choice; gather when it returns: laptop trips.jsonl (daemon side), fleet serve broker journals, daemon journal for 21:00–22:10 UTC.
  • Why the platform recycled the sandbox at 21:22 and 22:57: no platform-side reason is visible from inside the VM.

Transport findings from the same pass (code-cited; full analysis in the investigation report)

  • "proxy closed during CONNECT" decoded: the literal string (laptop-agent.py:78) fires on exactly one condition — EOF before the runtime proxy finishes answering a CONNECT. It is the runtime proxy closing mid-handshake, distinct from a refusal (non-200 → CONNECT refused: …) and from TCP-refused (an exception, surfaced via the broker as a 502). Three consecutive occurrences in the Mistral agent therefore mean the runtime proxy path itself was dropping handshakes during the window — consistent with the sandbox/runtime side being wedged, and NOT evidence of a laptop-daemon fault (the daemon is never reached when CONNECT itself fails).
  • Broker-mode failure chain: in broker mode, that same EOF makes tunnel_socket raise SystemExit, which the Python broker's except Exception does not catch — the handler thread dies silently, the client sees "broker closed", auto-retries once, then falls back to a direct re-POST. A timed-out /exec can consequently be submitted up to three times (broker attempt + client retry + direct fallback). Duplicate-execution risk on long execs is a real, separate defect worth its own fix.
  • Broker ownership flaps between implementations: the Python broker and fleet proxy serve share one socket; broker.log (untimestamped — a gap) shows them alternately owning it across boots, and at investigation time the Python fallback was the live broker — pool 12, no overflow wait — while the fleet broker (pool 50, 300 ms overflow wait) is what init-ensure.sh intends to launch with LAPTOP_AGENT_POOL=50. The two have materially different saturation behavior, so "which broker was live" is a variable in any future incident; making the broker log timestamped and the ownership deterministic belongs in the follow-ups.
  • The 660 s synchronous cap is ours: laptop-agent.py:108 (broker-socket timeout; the operative one) — a fleet-authored constant (daemon cap 600 + 60 headroom), not a platform default. The daemon caps a synchronous exec at 600 s total wall-clock per command regardless of output (output is buffered, never streamed; there is no idle-timeout reset, and /exec has no stdin channel at all — interactive programs like vim cannot run over it; detached jobs are the multi-hour path).

Actions taken in the same pass

  • Init FAILURES=1 loop root-caused and fixed (separate issue): sysstat apt-lock deferral; the marker now gets written and init stops re-running per-prelude.
  • Monitor + lane A + remaining repo-queue cron bodies migrated repo-first (hatch-personal a8f942c8d) per Drew's method.
  • Trip-log v2 designed (separate issue): four timestamps per trip so the next incident attributes each leg.
  • Quota-recorder laptop-broker redesign filed with recommendation (separate issue).

Acceptance criteria

  • The incident timeline and root-cause analysis are complete on this issue.
  • Every follow-up action is either filed as a linked issue or explicitly recorded as decided-against.
  • The responsiveness-loss trigger (post-boot wedge) is named with the evidence that supports it.

Activity

  1. dezren39 commented on Nov 4, 2026

    @dezren39
    MemberAuthor

    Investigation addendum — 2026-11-04 ~23:20 UTC (stage 1 complete; laptop power-on test staged)

    Shim verification (the Atlas coordinator's alarm does NOT reproduce). ~/tools/laptop-ssh.sh md5 = 5076becb0f01d80dc272ef6149a0857c (agent-delegating shim) and ~/tools/laptop-ssh-real.sh md5 = 95f647590274779bcaef7ea9a66f0670 (original SSH wrapper) — confirmed by md5sum, sha256sum, content header, and home-repo git log (last touch = the retirement commits; working tree clean). The laptop path is on the agent/proxy transport, NOT back on SSH. No restore was needed; the alarming measurement appears to have been a stale/fabricated read on the measuring side.

    fleet queue client behavior (probe, laptop off). fleet queue health --queue repo-health-code-pilot produced no output and was still blocked at a 25 s timeout; the session-proxy broker log did not grow during the call — the Rust queue client does not route via broker.sock (it carries its own proxy client) and it blocks/retries silently for a long time against an unreachable broker instead of failing fast. In the incident window the laptop was up, so this is not the incident mechanism; it is a herd amplifier after any future outage (dozens of jobs × long-blocking queue calls). Whether it pools or opens a CONNECT per call against a live broker is observable in the power-on window (connection watcher counts :3130 while a claim runs).

    Broker ownership flapping — observed live, twice in one hour. At ~23:04 UTC the socket owner was the Python broker (pid 1853, pool 12, no overflow wait). By 23:16 UTC the owner was fleet proxy serve (pid 22878, pool 50, 300 ms overflow wait). Nobody restarted it deliberately; the two implementations hand the socket off across boots and client auto-starts. Any incident analysis must record which broker was live — and during 21:00–22:10 UTC it is not recorded anywhere (broker.log has no timestamps). Follow-ups: timestamped broker log; deterministic single owner.

    Current baseline (watcher armed). A 10 s-cadence connection watcher is now logging to ~/workspace/goals/keep-the-four-repos-healthy/hidden_files/connection-watch-2026-11-04.log (broker identity+fds, established :3130 count, load, mem, agent/fleet process counts, last trip status). At rest with the laptop off: estab_3130 = 2–3, broker_fds = 8–10, load1 ≈ 11.5–11.9 on 4 CPUs (the box is hot even idle-ish: platform apt replay still running 16+ min, plus cron herd), trips failing 502 after ~16 s (broker retry chain against the dead target — matches the code: two attempts, then 502).

    Power-on window (staged, Drew-gated). Prepared: /tmp/connect-ramp.py — opens 50 → 64 → 128 concurrent tunnels through the real client path (laptop-agent.py's tunnel_socket) to the daemon port, one GET /health each, per-connection outcome + exact error strings logged to connect-ramp-2026-11-04.log beside the watcher log; stops at the first level with >5% failures. First minutes after power-on, in order: (1) watcher correlation — broker identity, :3130 count, trip latencies returning to ~0.4 s/200; (2) laptop-side evidence capture for 21:00–22:10 UTC (daemon-side trips.jsonl, daemon + broker journals) before the catch-up herd overwrites context; (3) one warm /exec sanity; (4) the ramp. Abort: any return of chat degradation stops the ramp (the only load this adds); the watcher keeps recording either way.

  2. dezren39 commented on Nov 4, 2026

    @dezren39
    MemberAuthor

    Correction to the addendum above — fleet queue probe result (supersedes two sentences)

    The completed probe output (it arrived after the addendum was written) changes the fleet-queue finding:

    • fleet queue health --queue repo-health-code-pilot (laptop off) did surface an error, after ~17.7 s: repo-queue: session proxy read failed: failed to fill whole buffer. The broker log did not grow during the call (302 lines before and after).
    • So the Rust queue client does use the session proxy (broker.sock) — the addendum's "does not route via broker.sock / blocks silently ≥25 s" is wrong and is retracted. (The error's own wording — "session proxy read failed" — is the proof.)
    • What actually happened: the client read a length-prefixed reply frame from the session proxy and hit EOF mid-frame ("failed to fill whole buffer"). With the laptop unreachable, that is the broker closing the connection without a complete reply — consistent with the known Python-broker defect in which tunnel_socket's sys.exit raises SystemExit, which do_request's except Exception does not catch, so the handler thread dies silently without replying (or with a broker ownership handoff in progress — ownership was flapping in that same ~23:13–23:16 window). A clean failure would have been a 502 frame, as ordinary laptop-agent client calls received.
    • Revised fleet-queue assessment: queue clients share the same session-proxy socket and broker as agent clients, so broker flapping and the silent-handler-death defect affect queue traffic too; and the queue client's failure mode against a dead laptop is a ~17.7 s hang ending in a framing EOF, not a fast failure. Still no evidence tying the migration to the incident window itself (laptop up, all traffic flowing 21:00–21:28); the power-on window observations now explicitly include a timed fleet queue health alongside the agent-path checks.
  3. added
    kind/infrastructureInfrastructure / host-portability work
    priority/normalOrdinary priority (the default)
    effort/sSmall: expected under 2 hours of work
    meta/enrichedIntake review done: acceptance criteria, links, and normalized labels added
    on Nov 5, 2026
  4. dezren39 commented on Nov 5, 2026

    @dezren39
    MemberAuthor

    Intake review

    Related: incident record for the 2026-11-04 afternoon responsiveness loss; the broker incident #5708 is a separate, later incident the same day. Notes: as an incident record, the deliverable is the completed timeline + root cause + filed follow-ups, not code. Risk: an unclosed incident record lets the same wedge recur unexamined. Suggested approach: finish the write-up, file any follow-ups as linked issues, then close.

    Validation: filed within the last hour and reviewed against its own body this run; no merged PR resolves it (the work it describes has not been implemented). Acceptance criteria appended to the body; labels normalized by the fleet monitor.

    🤖 Agent note · intake enrichment

    • Agent: fleet monitor (repo-fleet-monitor)
    • Session / ID: monitor run 2026-11-04 18:12 CST
    • Found via: monitor reconciliation
    • Task: Duty 2 intake enrichment (protocol §5)
  5. dezren39 commented on Nov 5, 2026

    @dezren39
    MemberAuthor

    Stage 2 results — laptop power-on window, 2026-11-04 18:19–18:35 CST

    (a) Connection ramp test — NO ceiling found up to 128 concurrent tunnels

    Ran the staged /tmp/connect-ramp.py (real client path: laptop-agent.py's tunnel_socket, one GET /health per tunnel to the daemon :4799), 2026-11-05T00:21:00–00:22:00Z. Log: hidden_files/connect-ramp-2026-11-04.log.

    Level Attempted OK Fail Wall
    50 50 50 0 6.5s
    64 64 64 0 8.2s
    128 128 128 0 14.6s

    Independent correlation (connection watcher, 10s cadence): estab_3130 peaked at 54 during the 50-level and 130 during the 128-level; every trip 200; broker stayed fleet proxy serve (pid 22878). Latency scales ~linearly with concurrency (serialized CONNECT setup) but nothing fails at 2.56× the production pool. The pool config was never touched: LAPTOP_AGENT_POOL=50 in ~/tools/init-ensure.sh before and after; the ramp only opens tunnels. Verdict: no connection ceiling exists at or below 128 concurrent; the incident mechanism remains the stage-1 conclusion (sandbox wedge + post-boot herd), not a transport ceiling. Supporting live checks in the same window: timed fleet queue health = 0.30s end-to-end; fleet secrets get = 0.41s; warm trips 184–525ms.

    (b) Laptop-side evidence for the incident window (15:00–16:57 CST / 21:00–22:57Z)

    • Journals are gone: the laptop's user AND system journals retain only the current boot (first entry 18:17:48 CST) — volatile journaling across the power-off. Journal evidence for the window no longer exists; that absence is itself recorded here.
    • The surviving record — daemon ~/.local/state/laptop-agent/trips.jsonl — shows a healthy daemon: 272 exec trips in hour 21Z, last pre-gap trip 21:30:16Z (exit 0, 10ms), only 2 nonzero exits all hour (ordinary workload exit-1s with normal stderr), longest daemon-side durations 217s/57s/46s all completed (long execs, not stalls). Silence 21:30:16Z → 00:18:47Z spans first the sandbox wedge (no calls arrived) and then the laptop power-off — the daemon logged nothing because nothing reached it, and it answered immediately at boot (00:18:47Z, exit 0).
    • Broker/opencode journals for the window: unrecoverable (same volatile journal). opencode.service, queue-broker.service, secrets-broker.service, laptop-agent.service all active and healthy post-boot; brokers verified through the real client route (see (a)).

    Stage-2 conclusion: the laptop side shows zero abnormality in the window. Combined with stage 1, the incident stays a sandbox-side wedge; the laptop path is exonerated on direct laptop-side evidence, not just trip-log inference.

    (c) Rust client connection behavior — code-cited (laptop ~/git/code, origin/main af0847d)

    Two layers, opposite answers:

    • Clients open a NEW connection per call. Every Rust client is a one-shot CLI process and dials fresh per invocation/roundtrip: fleet-proxy/src/client.rs:149 ensure_broker — new UnixStream::connect(broker.sock) + hello negotiation per call; fleet-queue/src/client.rs:100 — new TcpStream::connect per request to the queue-broker with Connection: close, read-to-end; fleet-queue/src/client.rs:182 unix_roundtrip — new UnixStream per roundtrip via the session proxy; fleet-secrets/src/lib.rs:264 — UnixStream::connect per call. These are local unix-socket / LAN hops (cheap); no cross-invocation cache exists or could exist for one-shot processes.
    • The expensive tunnels ARE pooled — in the broker. fleet-proxy/src/serve.rs:7-13,100 TunnelPool: per-port pools of warm CONNECT tunnels through the runtime proxy to the laptop; size from LAPTOP_AGENT_POOL, compiled default 50 (serve.rs:60ff — sized from the epic: one fleet multicall binary — search, queue, dispatch, proxy — with capability-selected builds #5412 benchmark: 12 cliffed at ~12 concurrent consumers, 50 covers the burst); checkout with bounded wait, overflow grows rather than failing. So per-call client churn terminates at the broker's unix socket; the :3130 CONNECT tunnels are reused from the pool.
    • Atlas CLI (pkgs/atlas-search): atlas-core/src/turso.rs:100-107 builds one ureq::Agent per transport instance (ureq pools keep-alive connections per agent) — reused within a run/service lifetime (atlas-search/src/service.rs:88,269), cold per one-shot CLI invocation, against Turso's HTTPS /v2/pipeline. No per-query TCP churn beyond the process boundary.

    Phase-1 additions (Drew steer 18:20 CST)

    • Init duration breakdown → filed as its own issue Init job duration: ~60s of every ~75s run is a telemetry du of nix-persist that times out and returns 'unknown' #5717: named restore steps total ~4s; ~60s of every ~75s run is one telemetry du -sh of nix-persist that hits its 60s timeout and returns unknown every time; secondary costs = quota snapshot (≤30s budget), net check ~3–4s; the sysstat apt path is minutes-long when it wins the lock race (now deferred). Removing/caching the du takes init to ~10–15s.
    • RustDesk wrapper cost (feeds design: remote desktop through the fleet brokers (RustDesk transport, secrets, pre-warming, virtual desktops) #5694): on the current boot the .rustdesk-wrapper process is not running (full /proc scan: absent; cost now 0%). On the previous boot the resource sampler (~/logs/resource/resource-2026-11-04.log) recorded it as the top CPU process in 30 samples at 26.9–32.4% sustained (19:13–20:03 UTC), and stage 1 read ~45% during the incident window — i.e. roughly a third to a half of one core, continuously, whenever it is present. No systemd unit and no file at the usual roots (~/.rustdesk-wrapper, ~/tools, ~/.openclaw) on this boot, so its launch path/cmdline could not be captured live; it appears with the platform/OpenClaw layer rather than any unit we own. Measured only, per instructions — not killed, replacement not built here.
  6. dezren39 commented on Nov 5, 2026

    @dezren39
    MemberAuthor

    WS-C — Connection performance: decomposition, round-trip census, design (2026-11-04 ~19:30 CST)

    Workstream WS-C/C of the sandbox performance program. All numbers below are from the client trip log + live probes this evening, cross-checked by a second method where consequential (the fabrication rule). Laptop footprint kept light/read-only; the ramp was NOT re-run — its outcome is consumed from the stage-2 comment above.

    1. trips.jsonl stats (client side, sandbox)

    File: ~/.local/state/laptop-agent/trips.jsonl, n=1149, span 2026-11-04T20:28:53Z → 2026-11-05T01:26:04Z (the log's entire life is today CST; it begins with the agent's first day). Status mix: 200 ×963, 502 ×119, none ×73 (6 trips unaccounted by status bucketing are non-200/502/none edge rows in path parsing — counts are by exact status field).

    Subset n p50 p90 p99 mean
    All trips 1149 523 ms 23,738 ms 100,412 ms 7,262 ms
    Status 200, <2 s (pure warm transport — long execs excluded) 800 369 ms 1,020 ms 1,797 ms 496 ms
    /exec, status 200, <2 s 779 369 ms 1,039 ms 1,810 ms 499 ms
    Status 502 119 16,294 ms 16,776 ms — —
    Status none (client died/timed out) 73 25,965 ms 29,606 ms — —
    /health, status 200 5 372 ms 799 ms — 444 ms

    The all-trips p90/p99 are dominated by (a) real long-running exec work and (b) the 16–26 s failure cluster — not by warm transport. Hourly warm p50 improved through the day: 471 ms (20Z) → 382 ms (21Z) → 337 ms (00Z) → 308 ms (01Z).

    2. Decomposition of a warm ~445 ms call (trip aedc705d4294 verified both sides: client 445 ms, daemon 1 ms)

    Component ms Basis
    Daemon work (trivial exec) 1–11 MEASURED — laptop daemon trips.jsonl (aedc705d4294 = 1 ms; live tail this evening = 5–11 ms)
    Client Python startup + client imports (wall only, outside trip) ~80–116 wall (baseline python3 -c pass: 46–75) MEASURED — repeated timed runs this evening
    Unix-socket hop client→session proxy ~0–4 MEASURED — local unix round-trip floor 0.1–4.2 ms in-process
    Pooled-tunnel HTTP request/response over runtime proxy :3130 + DERP hairpin ~170–600 (the entire remaining trip) MEASURED as a whole — in-process broker /health round trips 482–940 ms under this evening's load; same-minute trip pair below. INFERRED internal split (proxy forwarding vs DERP propagation vs daemon HTTP stack) — no instrumented breakdown exists inside the path
    Per-call CONNECT setup (warm path) 0 CODE — warm calls reuse a pooled tunnel; no CONNECT per call
    Cold CONNECT setup (when a tunnel must be created) ~1,200 (this evening) / ~1,800 (earlier measurement) MEASURED — same-minute pair: LAPTOP_AGENT_NO_BROKER=1 health trip 1,434 ms vs warm trip 212 ms right after; wall 1,592 vs 425 ms
    Token read / headers / JSON <1–few CODE — broker reads token per request from file (broker do_request); client↔broker framing is length-prefixed JSON (laptop-agent.py:_broker_roundtrip, _log_trip is one O_APPEND write after the reply)

    Per-call setup steps on the warm path, code-cited (Python client; the Rust fleet proxy serve now owns the socket — pid 22878 verified live — and mirrors this protocol per the stage-2 (c) citations):

    1. New unix socket to broker.sock per call — laptop-agent.py:117-122 (_broker_roundtrip); one length-prefixed JSON frame each way :123-138.
    2. Broker checks out a pooled tunnel (Python broker: laptop-agent-broker.py:85-92 pool_get; Rust: TunnelPool per stage-2 (c)) — no CONNECT unless pool empty/stale.
    3. Broker sends HTTP/1.1 request with X-Agent-Token (read from file per request) + X-Trip-Id over the tunnel — laptop-agent-broker.py:106-117; on any exception, ONE retry on a FRESH connection (new CONNECT) :103-125.
    4. Direct fallback path (broker bypassed): new TCP to :3130 + CONNECT with Proxy-Authorization, response read one byte at a time — laptop-agent.py:56-85 (tunnel_socket), then a fresh HTTPConnection per call :181-190.
    5. No TCP_NODELAY anywhere in the Python stack (grep: laptop-agent.py, laptop-agent-broker.py, laptop-agent-daemon.py — zero hits); daemon is HTTP/1.1 + Content-Length, single wfile.write (laptop-agent-daemon.py:190-199). Nagle/delayed-ACK contribution is a plausible INFERRED slice of the warm RTT, unproven without packet capture.

    Live probes this evening (sandbox load ~15 on 4 CPUs, laptop load 5–12 — numbers are pessimistic vs the 00Z hourly p50 of 337 ms): 5× exec -- true wall 346/382/614/719/604 ms; health wall 344 ms; exec-batch of 10 trivial commands in ONE request: 483 ms wall total.

    3. Round-trip census (1 transport round trip = 1 trip through the session proxy over a pooled tunnel)

    Operation Round trips today Implied warm wall
    (a) Single trivial exec 1 ~0.35–0.7 s (trip p50 369 ms + ~90 ms client startup)
    (b) fleet queue claim — ONE claim 1 — call("/claim") → one broker roundtrip → one unix roundtrip (repo-queue crate crates/repo-queue/src/main.rs: cmd_claim, call, broker_roundtrip, unix_roundtrip). The full claimant launch flow is claim+lane+bind = 3 separate calls/invocations ~0.3–0.6 s per claim; ~1–2 s per launch flow
    (c) Small file fetch from laptop 1, via a hack — there is NO file verb; fetch is an exec running base64 -w0 <file> (measured: /etc/hostname, 301 ms wall), 1 MiB/stream cap, +33% size, no offsets/resume. Detached-job polling is the other multi-trip shape: run = 1 + poll every 3 s (client-side sleep, laptop-agent.py poll loop) 1 trip + encoding overhead

    Note: fleet queue health measured 5,774 ms and 2,100 ms in two probes tonight (vs 0.30 s in the stage-2 window) — it resolves secrets ("resolved via bitwarden") in addition to querying, i.e. multiple internal round trips, and is highly load-sensitive. Flagged in the census issue.

    4. Ramp outcome (consumed, not re-run)

    Stage-2 comment above: 50/64/128 concurrent tunnels, zero failures, wall 6.5/8.2/14.6 s — latency scales ≈ linearly (serialized CONNECT setup), no ceiling ≤128, pool left at 50. Conclusion for design: pool SIZE is not the constraint; per-RTT cost and round-trip COUNT are. Raising the pool to 128 buys nothing measured and worsens the recovery stampede.

    5. Design filed (Drew's bar: most performant possible — wire format and round trips both on the table)

    6. Implementation decision

    No code fix applied. The only small-fix candidates live in the Python client/broker, but the live broker is the Rust fleet proxy serve (verified pid 22878) — Python-path changes (e.g. TCP_NODELAY in tunnel_socket, recv(1) CONNECT parsing) would not move a single live number, and touching the live Rust proxy during another coordinator's switch/ramp window violates the light-footprint constraint. The honest small wins are already filed as #5758 items. If the Python broker ever retakes the socket, the byte-at-a-time CONNECT read (laptop-agent.py:76-82) is the first fix to make.

    Open unknowns

    • Internal split of the warm RTT (runtime-proxy forwarding vs DERP propagation vs HTTP stack behaviour) — needs packet timing inside :3130, which no current log records.
    • Whether fleet proxy serve sets TCP_NODELAY / how its TunnelPool checkout wait behaves at saturation (source is on the laptop checkout; not read tonight to keep the laptop footprint light).
    • Why fleet queue health varies 0.30 s → 5.8 s: internal round-trip count not instrumented client-side.
  7. dezren39 commented on Nov 5, 2026

    @dezren39
    MemberAuthor

    WS-C correction/addendum (same evening) — fleet-proxy source located on the sandbox

    My WS-C comment above listed "whether fleet proxy serve sets TCP_NODELAY" as an open unknown and said the source was not read. That was incomplete: the source IS on the sandbox in the roadmap worktree ~/git/wt-code-roadmap-2026-11-04/pkgs/fleet/crates/fleet-proxy/ (read after the comment posted; the worktree is a branch snapshot, so treat line numbers as indicative for the live binary, not proof of its exact build):

    • The Rust tunnel DOES set TCP_NODELAY: crates/fleet-proxy/src/tunnel.rs:198 — stream.set_nodelay(true). So the Nagle/delayed-ACK hypothesis in my decomposition applies at most to (a) the Python fallback broker/client stack (no NODELAY anywhere) and (b) the laptop-side Python daemon socket (ThreadingHTTPServer, no NODELAY) — NOT to the live sandbox-side Rust tunnel. This strengthens the main conclusion: the warm ~170–600 ms is path/propagation + proxy forwarding cost, not a local Nagle artifact on the primary path.
    • The Rust broker mirrors the Python constants: serve.rs:42 KEEPALIVE_S=180, idle-exit default 3600 s (checked on a 5 s tick, serve.rs:315-334), pool size from LAPTOP_AGENT_POOL (serve.rs:56ff). The header comment in this snapshot still says "default 12" while Incident record 2026-11-04: afternoon responsiveness loss — sandbox wedged after post-boot herd (daemon restart, 88-min sampler silence); laptop path exonerated 21:00–21:28 UTC #5701 stage-2 (c) records the compiled default as 50 on the laptop checkout — the live sandbox launch sets LAPTOP_AGENT_POOL=50 explicitly in ~/tools/init-ensure.sh, so the live value is 50 regardless.

    Net effect on the filed design (#5756/#5757/#5758): none to the proposals; the TCP_NODELAY acceptance item in #5756 should be read as "keep/extend the existing tunnel.rs nodelay to any new framed transport and to the daemon side", not as net-new on the client tunnel.

  8. dezren39 commented on Nov 5, 2026

    @dezren39
    MemberAuthor

    WS-C audit note: the three design issues filed with the WS-C comment above are #5756 (multiplexed streams), #5757 (round-trip coalescing + file verb), and #5758 (fail-fast / pool policy). The references in the two WS-C comments above have been edited in place to these numbers — an earlier draft of this note pointed at #5722/#5723/#5724 (unrelated issues) because a tool output in the filing session returned the wrong creation URLs; verified correct numbers via gh search + api before editing.

  9. dezren39 commented on Nov 5, 2026

    @dezren39
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    Literature cross-link (Drew's 2026-11-04 ask): the bufferbloat technical review is filed as PR #5930 — doc/2026-11-04_bufferbloat-technical-reference.md.

    What it does with this incident's numbers (WS-C measurements: warm p50 369 ms vs 1–11 ms daemon work; 502 trip p50 16.3 s; no-status 26.0 s; serialized connection setup):

    Verdict in one line: bloat plausibly owns the tail of this problem (herds, bulk interference), not the warm median — the failure tax looks more like stacked timeouts/retries than standing queues, and measurement 6 in the doc would settle that.

  10. added a commit that references this issue on Nov 5, 2026
  11. dezren39 commented on Nov 5, 2026

    @dezren39
    MemberAuthor

    Detached du measurement dropped entirely, per Drew's ruling (2026-11-05 01:50 CST: "yes drop it").

    Removed (dezren39/hatch commit 1017de239, pushed to main): in tools/init.sh — the detached setsid nohup … du -sh /home/hatch/nix-persist … cache-writer, the cache read that fed nix_persist_size, and the stale comments/log wording (nix_persist=deferred → unmeasured). nix_persist_size now keeps its truthful unknown default; disk usage is covered by the #5925 telemetry rollup as designed.

    Zero consumers, verified fresh: rg --no-ignore --hidden '\.nix-persist-size' across all of /home/hatch (public repo + hatch-personal + workspace) returns only tools/init.sh itself (before the edit), the cache file, and doc/log/transcript mentions — no code reader anywhere; targeted greps of hatch-personal/scripts, systemd user units, and the nix-program goal workspace were also empty; no systemd unit or timer was involved (the detached launch lived only in init.sh).

    Live pieces: a detached du from the 07:50 init was still running — its process group was killed. The cache file logs/.nix-persist-size was moved to recoverable trash (trash_id 20261105-080103-efadcb18be984307a7b7bbd359d42d05, restorable until 2026-12-05).

    Verified: full run of the edited init.sh exited 0 and rewrote ~/logs/init-status (boot 139684af, result=SUCCESS, nix_persist_size=unknown, all other keys intact); init-ensure.sh exits 0 instantly; the cache file was NOT recreated by the run and no detached du exists.

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