A fresh same-session prior within the TTL is no longer sufficient to price
the text counterfactual warm: deriveBaselineWarmth now also requires the
static-prefix hash (system_sha8) to match. When opencode rotates the system
prompt / tool docs mid-session, the cacheable prefix changes, so a text-only
client would hit a new provider cache key too — pricing it warm against a
cold actual fabricated a huge phantom "loss" (the dashboard's 800%-worse
report). cr>0 still rescues a genuine warm read with no in-memory prior.
Wired through update(), replay(), and aggregateSessions via system_sha8.
Also surface losses honestly in the recent table (Saved/lost: negative
deltas in red instead of hidden as "—") and clarify headings as
billing-equivalent input tokens. Docs updated to match.
The savings accounting priced the text baseline as cold whenever pxpipe's own
image cache missed this turn (cr==0), fabricating a 1.25x create the text path
would never have paid and inflating reported savings ~2x. Decouple them: the
text prefix reads warm whenever a fresh same-session prior exists within the
300s TTL (wall-clock), unioned with an observed read (cr>0) for the post-restart
case. Centralised in deriveBaselineWarmth; used by all three call sites
(sessions, dashboard, fragments).
Empirical replay over ~/.pxpipe/events.jsonl (13,402 message rows): honest
headline 504.6M tokens saved vs the old cr-gated 1.05B; 1,409/12,305 fresh-prior
rows (11.4%) read warm despite a busted image cache. Dashboard now narrates the
busted-image case explicitly. Adds baseline/sessions/context-map regression
tests. Measurement only — no change to proxy behavior.
typecheck + 600 tests + build all green.
b9418bf repriced cr>0-but-no-prior turns warm in dashboard.ts (update + replay)
but left the identical gate in sessions.ts unfixed — so the Sessions panel still
fabricated inflated savings after a restart/eviction or on the first tracked turn
(a cr>0 turn priced cold bills the text counterfactual a 1.25x create on a prefix
we KNOW was cached). Mirror the dashboard fix so "honest cache math" holds on every
panel.
- sessions.ts: warm follows the observed read (cr>0) alone; with no fresh prior,
assume the cacheable prefix was fully reused (prevCacheable = cacheable) rather
than mispricing a known-warm read.
- sessions.test.ts: the "real prefix compression" case had cr=100 on its first
turn (observably warm) yet asserted the cold-priced 22490 fabrication; corrected
to the honest 1790 (warm) + 95 = 1885. Now a regression guard for this fix.
- dashboard.ts: drop the stale "no per-session state" replay comment — replay now
mirrors update()'s per-session warmth.
Found by adversarial review of b9418bf. 462 tests pass; tsc clean.
Collapse old conversation history into rendered PNG sections so the model
reads a compact image instead of re-billed text, while preserving prompt
caching and tool-call behavior. Measures real vs compressed token/cost.
Core:
- GPT history collapse (openai-history.ts): append-only, o200k token-length
sectioning. Sections seal only at a tool-closed boundary (open call-id set
empty), so a function_call and its function_call_output never split across
the collapse cut. Fixes the OpenAI 400 "No tool call found for function
call output with call_id ..." that hit long Responses-API sessions.
- Anthropic cache contract (history.ts): append-only per-chunk rendering;
cache_control markers are preserved/moved, never added; chunk boundaries
align with caller marker seams for byte-stable prefix caching.
- GPT image budget (openai.ts): detail:'original' for gpt-5.x, flagship
vision-multiplier fix, patch cap; schema-strip preserves real descriptions.
- Savings accounting (openai-savings.ts): cached_tokens + vision-token basis.
Model scope (applicability.ts):
- Default imaged scope = claude-fable-5 + gpt-5.6.
- gpt-5.5 and claude-opus-4-8 stay opt-in: same pipeline, but they degrade
reading dense imaged history (gist drift), so silently imaging them by
default is wrong. Promotion is gated on an OCR/recall threshold.
Dashboard: GPT + Anthropic rendering, per-family model toggles, persisted
metrics, thumbnail-expired session UI, reflow/newline handling.
Tests: cache-alignment (GPT + Anthropic), history sectioning + tool-boundary
invariants, savings, dashboard, sessions/restart-restore. 452 passing.
Per-turn and per-session savings are the real baseline_eff - actual_eff with no
floor: a net-losing turn (cache_create-heavy image rewrite that costs more than
the text prefix it replaced) now reports the real loss instead of a fabricated
0. Updates baseline.ts and the caller comments that claimed a >=0 clamp the code
never applied -- the negative is intended and covered by tests/sessions.test.ts.
The headline saved%/saved$ numbers are now MEASURED, not estimated:
baseline = sum of /v1/messages/count_tokens(originalBody).input_tokens
actual = sum of (input + cache_create×1.25 + cache_read×0.10)
saved = baseline − actual
Output is excluded from both sides — it's identical with or without
compression (same prompt → same response), so it cancels in the
numerator and would only drag the percentage toward zero. The proxy
now makes one parallel side call to /v1/messages/count_tokens (free,
no billing) before forwarding /v1/messages, and the result lands on
TransformInfo.baselineTokens → TrackEvent.baseline_tokens → the
DashboardState rollup.
Removed (~280 lines of dead code):
- FALLBACK_ALPHA, FALLBACK_ALPHA_LOW, FALLBACK_ALPHA_HIGH constants
- estImageTokens(), baselineCost(), effectiveCost() helpers
- FitSample interface + FIT_SAMPLE_CAP + fitSamples ring buffer
- DashboardState.fitCosts() (~218 lines of OLS regression)
- Three-mode ladder (joint / constrained / stale) and all UI for it
- saved_pct_low/high, saved_effective_tokens_low/high range fields
- renderSavingsMath() range/regime branches
- m_pct_regime DOM node + its color/text wiring
- cost_fit payload field + all frontend consumers
/proxy-stats payload is now: requests, compressed_requests,
baseline_input_tokens, actual_input_weighted, saved_input_tokens,
saved_pct, saved_usd, pricing_assumptions, uptime_sec,
compression_enabled. Nothing else.
The recent-requests table now shows baseline / actual / saved per
row (input-side, matching the cards) instead of the old img-tok
estimate + effective_actual (which mixed output × 5 in inconsistently).
Sessions panel: per-session tokensSavedEst now uses the same real
baseline−actual formula. Events without both a count_tokens probe
AND an upstream usage block don't contribute to the rollup — no
synthetic 4-char/tok fallback.
Tests:
- dashboard-fit.test.ts: deleted (fitCosts is gone)
- proxy-usage.test.ts: inverted the privacy regression — count_tokens
is now explicitly expected as the one whitelisted side path; added
baselineTokens-attachment and count_tokens-failure-survives tests
- sessions.test.ts: rewrote the two savings tests against the new
baseline_tokens + usage formula
The sessions table previously only supported per-row deletion via the
"del" button — no way to clear many at once. Add an industry-standard
multi-select pattern.
Pattern follows Gmail / GitHub / Linear / Vercel:
- Leftmost cell on each row is a checkbox; data-id binds to session id.
- Header checkbox is tri-state (empty / indeterminate / all-on-page)
driven by a single source of truth (selectedSessionIds: Set<string>).
- Shift-click on a row checkbox does range-select from the
last-clicked anchor to the current row, applying the new checked
state to every row in between (macOS Finder / Gmail convention).
- Contextual action bar slides in above the table when ≥1 row is
selected, showing "N selected · Delete selected · Clear (Esc)".
- Confirm modal shows count + first 3 session id prefixes + "and N
more" for sanity-check before destructive action.
- Esc key clears the selection (no-op when an input is focused).
- Selection is keyed on session id and reapplied after each diff
render — innerHTML rewrites no longer clobber checked state.
- Vanished sessions auto-drop from selection.
Backend:
- PruneOptions gains sessionIds?: string[] alongside the existing
single sessionId. Unknown ids are silently skipped (race-safe with
concurrent prunes). Composes with sessionId if both are set.
- handlePrune plumbs sessionIds through; the bulk-delete action calls
/api/sessions/prune once with all ids.
- 3 new selectSessionsToRemove tests: bulk select, unknown-id skip,
sessionId+sessionIds composition.
Tests: 266 → 269 (+3). Typecheck + build clean.
The dashboard headline was showing 0% saved because the math was
apples-to-oranges:
- orig_chars = static slab + tool docs ONLY (~135 KB)
- image_count = ALL images including reminders + tool_results (~33)
- txtReplaced = 135k/4 = 33.7k tokens
- imgTokensEst = 33 × 2500 = 82.5k tokens
- extraText = max(0, 33.7k - 82.5k) = 0 ← clamped negative
- baseline == paid → 'saved 0%' headline despite real savings happening
Two fixes:
1. Track 'compressedChars' separately from 'origChars'. It accumulates
only when a block actually image-renders (passes the break-even gate
AND any per-block min thresholds). Includes the static slab + all
compressed reminders + all compressed tool_results.
2. Remove the Math.max(0,...) clamp in baselineCost(). Negative savings
surface honestly — they're the signal that small-block compressions
are cost-bleeding, which the break-even gate is supposed to prevent.
Wires:
- TransformInfo.compressedChars (new field, mandatory).
- All 4 image-render success paths accumulate (static slab + reminder
+ tool_result string branch + tool_result array branch).
- TrackEvent.compressed_chars (new optional field, emitted when > 0).
- dashboard.baselineCost() takes compressedChars now; clamp removed.
- sessions.aggregateSessions() also uses compressed_chars + honest math.
229/229 tests passing. Bundle stays at 496 KB gzipped.
Post-restart, the dashboard 'tokens saved' will show real numbers
including negatives. Empirically expect ~1-5% net positive in
steady-state cache-hit traffic.
Two distinct improvements in one slice:
1. History-image compression (Variant C — opt-in, default OFF).
New src/core/history.ts module:
- findClosedPrefixBoundary(): walks tool_use_id openSet, returns largest
fully-closed prefix index. Mid-flight tool_use blocks bail the collapse.
- blocksToText(): linearises content blocks for the history image. Drops
thinking blocks (per Opus 4.7+ docs: only most-recent must be bit-perfect),
renders tool_use args + tool_result inner text, emits [image] placeholder
for nested images.
- collapseHistory(): orchestrates. Applies isCompressionProfitable() gate.
Returns a synthesized {role:'user', content:[text,image,text]} prepended
message + the elided turns dropped from messages[].
New TransformOptions: compressHistory (default false), historyKeepTail (4),
historyMinPrefix (10). Wired through src/node.ts + src/worker.ts as
COMPRESS_HISTORY / HISTORY_KEEP_TAIL / HISTORY_MIN_PREFIX env vars.
Cache_control: history-image carries NO cache_control on this first cut.
Static slab keeps its 1 breakpoint. Conservative — telemetry will reveal
whether the cache-miss rate on history images warrants the round-3
rebalance in a follow-up slice.
29 new tests in tests/history.test.ts: closed-prefix detection (parallel
tool calls, mid-flight, openSet straddling), block linearisation, full
collapse flow, isCompressionProfitable gate firing on small histories.
2. Per-session savings: honest formula (fixes task #63).
Previous src/sessions.ts computed saved = orig_chars - image_bytes — a
nonsense comparison of chars to PNG bytes, then clamped via Math.max(0,...).
Result: charsSaved/tokensSavedEst was 0 for every session including ones
with hundreds of MB of compressed traffic.
New formula mirrors src/dashboard.ts:
textTokens = orig_chars / 4
imageTokens = image_count × 2500
tokensSaved = textTokens − imageTokens (CAN be negative)
Negatives are NOT clamped — they surface the cost-bleed on small-block
compressions that the per-block break-even check is supposed to prevent.
2 new tests: positive-net case, all-negative case (must report negative).
229/229 tests passing. Bundle ~500 KB gzipped.
Pivot from prior CLI subcommands (stats, sessions) to dashboard-based UI.
bin/cli.js becomes a minimal proxy starter; all functionality lives at
http://127.0.0.1:47821/.
New endpoints:
GET /api/sessions.json — session list + Claude Code mapping
GET /api/sessions/:id.json — session detail (bodies redacted by default)
POST /api/sessions/prune — dry-run-first cleanup with atomic rewrite
GET /api/disk.json — events.jsonl + 4xx-bodies disk usage
GET /api/stats.json — full-history aggregate (replaces CLI 'stats')
GET /sessions/:id — HTML detail page
Dashboard HTML extended with sessions panel + stats panel + cleanup panel.
Smooth-poll: 2s tick for legacy live counters, 5s tick for sessions/stats/disk.
Session rows diff-rendered (no full-table flash). Destructive actions show
window.confirm() with dry-run preview of impact.
Session mapping: synthetic ID from first_user_sha8 (already on every event)
+ opportunistic enrichment by fingerprinting against ~/.claude/projects/*.jsonl.
Falls back gracefully if Claude Code's session dir is missing.
Atomic events.jsonl rewrite (write to .tmp, fsync, rename) preserved from
the prior CLI design — trigger is now HTTP POST.
+51 new tests (33 sessions + 18 dashboard-api). 149/149 total.
Steven