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.
- keepSharp: caller predicate pins exact-match-critical blocks (IDs, hashes,
paths) as text, overriding the chars/token heuristic. Reported via
info.keptSharpBlocks. Never forces imaging; throwing predicate = false.
- emitRecoverable: optional recovery map (block -> original text + provenance)
so a stateful caller can re-inject or re-fetch imaged content. The recover
half of the fidelity contract; documented mitigation for lossy recall.
- edge/Workers-safe: process.env read is typeof-guarded; @napi-rs/canvas moved
to devDependencies (atlas is build-time only, runtime PNG encoder is pure-JS).
- comments: trimmed ~1,640 lines of essay/derivation/changelog narration across
src/ (transform.ts -73%), keeping one-line rationale; deep math points to docs/.
- New exports/types in index.ts + library.ts; +12 tests (keep-sharp, recoverable).
Build clean; 354/354 tests pass.
Tokens are the durable invariant; the dollar figure is a pricing-dependent
consequence that evaporates if Anthropic reprices.
- README: headline + intro now lead with input-token reduction; the
~59-70% end-to-end bill is demoted to a downstream effect 'at current
Fable list prices', with the dollar math pointed to the FAQ
- dashboard: stop claiming Claude's replies are 'never compressed' (false
for any session past keepTail) — scope to latest messages + live output
Demo clip moved to Google Drive (committed copy was too low-res); README keeps the preview thumbnail linking to the Drive video. Restoring the thumbnail also un-breaks the demo image on the npm 0.3.0 page. Version 0.3.0 -> 0.3.1 + CHANGELOG.
Attach the recorded plain-vs-pxpipe demo (cost-ab fix + effective-context recall) plus a poster thumbnail, embedded in a new Demo section with an honest caption (Opus opt-in; demo 2 shows pxpipe surfacing the lossy-count limit rather than fabricating). Fable headline clip to follow when Fable is back.
The library-use constants table still showed the pre-0.3.0 values (DENSE_CONTENT_CHARS_PER_IMAGE 5000, MAX_HEIGHT_PX 1568), contradicting the 'how it works' section and the shipped code. Updated to 1932 / 92160 + DENSE_CONTENT_COLS 384; test count 323->342; 'Fable-5 only' -> 'Fable-5 by default, Opus opt-in'.
- Remove eval/corpus/{sessions,text-blocks}.json from the repo — they are real captured transcripts (file paths, project names, message content). gitignore eval/corpus/; local copies kept for the eval scripts.
- gen_sweep.mjs: replace a hardcoded /Users/<name> absolute import with a relative path.
- README: 'holds ~92k readable chars' -> 'up to ~92k chars' (don't overclaim legibility at the new page density).
- CHANGELOG: note OCR legibility at the larger page size is not independently re-eval'd.
Fable 5 / Opus 4.8 accept up to 2576px / 4784 visual tokens per image, but a
request with >20 images (pxpipe always sends many) is held to the stricter
<=2000px/side rule, so the real ceiling is ~1932x1932 (1928x1928 = 69x69 = 4761
tokens). MAX_HEIGHT_PX 1568->1932; dense tool/history pages now render at
DENSE_CONTENT_COLS=384 / DENSE_CONTENT_CHARS_PER_IMAGE=92160 (1928x1928 full
page) -- fewer image blocks at the same OCR-validated 5x8 cell. The static slab
is unchanged (313 cols / 1573x1280).
Also fixes a regression the code review caught: the break-even gate,
truncateForBudget, and estimateImageCount predicted against the slab geometry
(313 cols / 159 rows) while the dense renderer emits 384 cols / 240 rows, so
large tool_results were truncated far earlier than the 10-image cap required --
silently dropping output that would have rendered. A per-page char budget is
threaded through the prediction chain (defaults to READABLE so the slab and unit
tests are byte-identical) plus a denseGateGeometry helper, so the gate prices the
same page the renderer actually produces.
- ON 47823 / OFF 47824 with own PXPIPE_LOG files: operator session can
never pollute bench measurement (separation by construction)
- resume = skip existing patch files; clean stop on quota errors
- Docker grading documented as proxy-free (no model calls in containers)
- README: mention Pro pilot alongside Lite
Does the model actually read pixelpipe's render, or coast on memorized answers?
- novel random-number problems (un-memorizable): text 100% vs image 93% (-7pp real reading tax)
- GSM8K (in training data): 97% vs 96% -- inflated ~3pp by recall
- verbatim recall from a dense render: 0/15
README 'Benchmarks' section leads with the clean 93% and reports the failure
rows too (no cherry-pick). Harness in eval/gsm8k/: gen_novel.py, render_cfg.mjs
(pixelpipe's real renderTextToPngs), bench.py -- claude -p, exact-match grading.
Widen the model gate to /^claude-opus-4-(?:[7-9]|[1-9]\d)(?:-|$)/ (Opus 4.7
and newer; previously 4.6/4.7). Wire isPixelpipeSupportedModel into the proxy
boundary in proxy.ts — the proxy previously gated on economics only and
ignored the model, so it compressed 4.8 traffic despite the docs claiming a
4.6/4.7 scope. Unsupported models now pass through with reason
'unsupported_model'.
Update public-api tests to the 4.7+ spec (320/320 pass).
Correct the docs to live measurement: reverse the POSTMORTEM "dead" verdict
(pixelpipe is a lossy gist-compressor saving ~68% on real dense Claude Code
traffic; the verbatim 0/15 needle finding stands as a caveat, not the
verdict), rewrite README Status/Limitations, and add a correction pointer to
the eval README. Original POSTMORTEM body preserved below the correction.
BREAKING CHANGE: Opus 4.6 and older are no longer supported.
Verbatim-risk guard (skip imaging unique IDs/hashes/exact values) still pending.
Steven Chong