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6 Commits

Author SHA1 Message Date
Kpa-clawbot 467b01a1b3 fix(#1285): exclude RTC-reset outliers from clock-skew hash median + recent bad count (#1288)
Red commit: 97c9a22a55 (CI:
https://github.com/Kpa-clawbot/CoreScope/commit/97c9a22a55b07d1576c579aa9d23b290dad33eb6/checks)

Fixes #1285.

## What was broken

**Bug A — outlier-dominated hash-evidence median.** On the per-hash
evidence panel a single observer reporting an RTC-reset advert (firmware
emitting factory timestamp, ~700d off) dragged the displayed median to
"median corrected: -704d 18h" even when every other observer of that
hash saw a normal value.

**Bug B — false "N of last K had nonsense timestamps" warning.**
`recentBadSampleCount` lumped RTC-reset adverts in with "bimodal-bad"
samples. On the repro node every recent skew was -16…-22s (healthy), but
the lone RTC-reset advert that landed inside the recent window was
counted as bad → "3 of last 5 adverts had nonsense timestamps" fired and
the node was misclassified `bimodal_clock`.

Root cause of B: the recent-window split (`cmd/server/clock_skew.go`
~L575) classified anything `|corrected skew| > 1h` as "bad". That
conflates true bimodal RTC oscillation (1h…24h) with factory-timestamp
resets (>24h, already surfaced via the RTC-reset badge).

## Fix

- New `rtcResetOutlierThresholdSec = 24h`. Rationale: real µC drift is
sub-second/advert; real bimodal RTC misbehaves in the hours range;
anything >1d is not a drift signal.
- Recent-window split puts `|skew| > 24h` in a third bucket excluded
from both `recentSampleCount` and `recentBadCount`.
- New `hashEvidenceMedian()` filters outliers before computing the
per-hash median. UI labels the hash "insufficient data (N RTC-reset
outliers excluded)" when every observer saw a reset-shaped advert.
- Three pre-existing #845 tests used -50M-sec "bad" samples (RTC-reset
range) — re-pointed to -7200s (true bimodal range), what `bimodal_clock`
actually models.

## Preflight overrides
- check-branch-clean: cross-stack: justified — backend computes
counts/median; frontend renders the new label.

## Browser verification
Confirmed staging node `c0dedad…` repro matches the test fixture. No new
CSS vars.

## E2E assertion added
`cmd/server/clock_skew_issue1285_test.go:81` and `:103`.

---------

Co-authored-by: corescope-bot <bot@corescope.local>
2026-05-19 01:17:12 -07:00
Kpa-clawbot b47587f031 feat(#690): expose observer skew + per-hash evidence in clock UI (#906)
## Summary

UI completion of #690 — surfaces observer clock skew and per-hash
evidence that the backend already computes but wasn't exposed in the
frontend.

**Not related to #845/PR #894** (bimodal detection) — this is the UI
surface for the original #690 scope.

## Changes

### Backend: per-hash evidence in node clock-skew API (commit 1)
- Extended `GET /api/nodes/{pubkey}/clock-skew` to return
`recentHashEvidence` (most recent 10 hashes with per-observer
raw/corrected skew and observer offset) and `calibrationSummary`
(total/calibrated/uncalibrated counts).
- Evidence is cached during `ClockSkewEngine.Recompute()` — route
handler is cheap.
- Fleet endpoint omits evidence to keep payload small.

### Frontend: observer list page — clock offset column (commit 2)
- Added "Clock Offset" column to observers table.
- Fetches `/api/observers/clock-skew` once on page load, joins by
ObserverID.
- Color-coded severity badge + sample count tooltip.
- Singleton observers show "—" not "0".

### Frontend: observer-detail clock card (commit 3)
- Added clock offset card mirroring node clock card style.
- Shows: offset value, sample count, severity badge.
- Inline explainer describing how offset is computed from multi-observer
packets.

### Frontend: node clock card evidence panel (commit 4)
- Collapsible "Evidence" section in existing node clock skew card.
- Per-hash breakdown: observer count, median corrected skew,
per-observer raw/corrected/offset.
- Calibration summary line and plain-English severity reason at top.

## Test Results

```
go test ./... (cmd/server) — PASS (19.3s)
go test ./... (cmd/ingestor) — PASS (31.6s)
Frontend helpers: 610 passed, 0 failed
```

New test: `TestNodeClockSkew_EvidencePayload` — 3-observer scenario
verifying per-hash array shape, corrected = raw + offset math, and
median.

No frontend JS smoke test added — no existing test harness for
clock/observer rendering. Noted for future.

## Screenshots

Screenshots TBD

## Perf justification

Evidence is computed inside the existing `Recompute()` cycle (already
O(n) on samples). The `hashEvidence` map adds ~32 bytes per sample of
memory. Evidence is stripped from fleet responses. Per-node endpoint
returns at most 10 evidence entries — bounded payload.

---------

Co-authored-by: you <you@example.com>
2026-05-02 10:30:54 -07:00
Kpa-clawbot 441409203e feat(#845): bimodal_clock severity — surface flaky-RTC nodes instead of hiding as 'No Clock' (#850)
## Problem

Nodes with flaky RTC (firmware emitting interleaved good and nonsense
timestamps) were classified as `no_clock` because the broken samples
poisoned the recent median. Operators lost visibility into these nodes —
they showed "No Clock" even though ~60% of their adverts had valid
timestamps.

Observed on staging: a node with 31K samples where recent adverts
interleave good skew (-6.8s, -13.6s) with firmware nonsense (-56M, -60M
seconds). Under the old logic, median of the mixed window → `no_clock`.

## Solution

New `bimodal_clock` severity tier that surfaces flaky-RTC nodes with
their real (good-sample) skew value.

### Classification order (first match wins)

| Severity | Good Fraction | Description |
|----------|--------------|-------------|
| `no_clock` | < 10% | Essentially no real clock |
| `bimodal_clock` | 10–80% (and bad > 0) | Mixed good/bad — flaky RTC |
| `ok`/`warn`/`critical`/`absurd` | ≥ 80% | Normal classification |

"Good" = `|skew| <= 1 hour`; "bad" = likely uninitialized RTC nonsense.

When `bimodal_clock`, `recentMedianSkewSec` is computed from **good
samples only**, so the dashboard shows the real working-clock value
(e.g. -7s) instead of the broken median.

### Backend changes
- New constant `BimodalSkewThresholdSec = 3600`
- New severity `bimodal_clock` in classification logic
- New API fields: `goodFraction`, `recentBadSampleCount`,
`recentSampleCount`

### Frontend changes
- Amber `Bimodal` badge with tooltip showing bad-sample percentage
- Bimodal nodes render skew value like ok/warn/severe (not the "No
Clock" path)
- Warning line below sparkline: "⚠️ X of last Y adverts had nonsense
timestamps (likely RTC reset)"

### Tests
- 3 new Go unit tests: bimodal (60% good → bimodal_clock), all-bad (→
no_clock), 90%-good (→ ok)
- 1 new frontend test: bimodal badge rendering with tooltip
- Existing `TestReporterScenario_789` passes unchanged

Builds on #789 (recent-window severity).

Closes #845

---------

Co-authored-by: you <you@example.com>
2026-04-21 09:11:14 -07:00
Kpa-clawbot a0fddb50aa fix(#789): severity from recent samples; Theil-Sen drift with outlier rejection (#828)
Closes #789.

## The two bugs

1. **Severity from stale median.** `classifySkew(absMedian)` used the
all-time `MedianSkewSec` over every advert ever recorded for the node. A
repeater that was off for hours and then GPS-corrected stayed pinned to
`absurd` because hundreds of historical bad samples poisoned the median.
Reporter's case: `medianSkewSec: -59,063,561.8` while `lastSkewSec:
-0.8` — current health was perfect, dashboard said catastrophic.

2. **Drift from a single correction jump.** Drift used OLS over every
`(ts, skew)` pair, with no outlier rejection. A single GPS-correction
event (skew jumps millions of seconds in ~30s) dominated the regression
and produced `+1,793,549.9 s/day` — physically nonsense; the existing
`maxReasonableDriftPerDay` cap then zeroed it (better than absurd, but
still useless).

## The two fixes

1. **Recent-window severity.** New field `recentMedianSkewSec` = median
over the last `N=5` samples or last `1h`, whichever is narrower (more
current view). Severity now derives from `abs(recentMedianSkewSec)`.
`MeanSkewSec`, `MedianSkewSec`, `LastSkewSec` are preserved unchanged so
the frontend, fleet view, and any external consumers continue to work.

2. **Theil-Sen drift with outlier filter.** Drift now uses the Theil-Sen
estimator (median of all pairwise slopes — textbook robust regression,
~29% breakdown point) on a series pre-filtered to drop samples whose
skew jumps more than `maxPlausibleSkewJumpSec = 60s` from the previous
accepted point. Real µC drift is fractions of a second per advert; clock
corrections fall well outside. Capped at `theilSenMaxPoints = 200`
(most-recent) so O(n²) stays bounded for chatty nodes.

## What stays the same

- Epoch-0 / out-of-range advert filter (PR #769).
- `minDriftSamples = 5` floor.
- `maxReasonableDriftPerDay = 86400` hard backstop.
- API shape: only additions (`recentMedianSkewSec`); no fields removed
or renamed.

## Tests

All in `cmd/server/clock_skew_test.go`:

- `TestSeverityUsesRecentNotMedian` — 100 bad samples (-60s) + 5 good
(-1s) → severity = `ok`, historical median still huge.
- `TestDriftRejectsCorrectionJump` — 30 min of clean linear drift + one
1000s jump → drift small (~12 s/day).
- `TestTheilSenMatchesOLSWhenClean` — clean linear data, Theil-Sen
within ~1% of OLS.
- `TestReporterScenario_789` — exact reproducer: 1662 samples, 1657 @
-683 days then 5 @ -1s → severity `ok`, `recentMedianSkewSec ≈ 0`, drift
bounded; legacy `medianSkewSec` preserved as historical context.

`go test ./... -count=1` (cmd/server) and `node
test-frontend-helpers.js` both pass.

---------

Co-authored-by: clawbot <bot@corescope.local>
Co-authored-by: you <you@example.com>
2026-04-20 22:47:10 -07:00
Kpa-clawbot ba7cd0fba7 fix: clock skew sanity checks — filter epoch-0, cap drift, min samples (#769)
Nodes with dead RTCs show -690d skew and -3 billion s/day drift. Fix:

1. **No Clock severity**: |skew| > 365d → `no_clock`, skip drift
2. **Drift cap**: |drift| > 86400 s/day → nil (physically impossible)
3. **Min samples**: < 5 samples → no drift regression
4. **Frontend**: 'No Clock' badge, '–' for unreliable drift

Fixes the crazy stats on the Clock Health fleet view.

---------

Co-authored-by: you <you@example.com>
2026-04-16 08:10:47 -07:00
Kpa-clawbot a815e70975 feat: Clock skew detection — backend computation (M1) (#746)
## Summary

Implements **Milestone 1** of #690 — backend clock skew computation for
nodes and observers.

## What's New

### Clock Skew Engine (`clock_skew.go`)

**Phase 1 — Raw Skew Calculation:**
For every ADVERT observation: `raw_skew = advert_timestamp -
observation_timestamp`

**Phase 2 — Observer Calibration:**
Same packet seen by multiple observers → compute each observer's clock
offset as the median deviation from the per-packet median observation
timestamp. This identifies observers with their own clock drift.

**Phase 3 — Corrected Node Skew:**
`corrected_skew = raw_skew + observer_offset` — compensates for observer
clock error.

**Phase 4 — Trend Analysis:**
Linear regression over time-ordered skew samples estimates drift rate in
seconds/day. Detects crystal drift vs stable offset vs sudden jumps.

### Severity Classification

| Level | Threshold | Meaning |
|-------|-----------|---------|
|  OK | < 5 min | Normal |
| ⚠️ Warning | 5 min – 1 hour | Clock drifting |
| 🔴 Critical | 1 hour – 30 days | Likely no time source |
| 🟣 Absurd | > 30 days | Firmware default or epoch 0 |

### New API Endpoints

- `GET /api/nodes/{pubkey}/clock-skew` — per-node skew data (mean,
median, last, drift, severity)
- `GET /api/observers/clock-skew` — observer calibration offsets
- Clock skew also included in `GET /api/nodes/{pubkey}/analytics`
response as `clockSkew` field

### Performance

- 30-second compute cache avoids reprocessing on every request
- Operates on in-memory `byPayloadType[ADVERT]` index — no DB queries
- O(n) in total ADVERT observations, O(m log m) for median calculations

## Tests

15 unit tests covering:
- Severity classification at all thresholds
- Median/mean math helpers
- ISO timestamp parsing
- Timestamp extraction from decoded JSON (nested and top-level)
- Observer calibration with single and multi-observer scenarios
- Observer offset correction direction (verified the sign is
`+obsOffset`)
- Drift estimation: stable, linear, insufficient data, short time span
- JSON number extraction edge cases

## What's NOT in This PR

- No UI changes (M2–M4)
- No customizer integration (M5)
- Thresholds are hardcoded constants (will be configurable in M5)

Implements #690 M1.

---------

Co-authored-by: you <you@example.com>
2026-04-14 23:22:35 -07:00