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.
- src/dashboard/fragments.ts: server-side HTML fragment renderers reusing the
same JSON payloads (HTML and JSON surfaces can't drift)
- node.ts/dashboard.ts: /fragments/<name> routes (header, session-summary,
recent, latest, sessions, stats, toggle) with htmx polling + Alpine for
local state; toggle is a POST-returning-fragment htmx swap
- vendored htmx 2.0.4 + Alpine 3.14.9 in src/dashboard/vendor.ts (offline,
single-file npm package, no CDN)
- deleted Svelte components/stores/bundle build step; dropped svelte/vite
devDeps; build is now just tsc + esbuild
- tests: +5 fragment contract tests (routing, toggle state, HTML escaping of
source text, 404) - 339 total
Replace the hand-rolled dashboard with a Svelte component tree (App +
Sessions / StatsTable / LatestPng / RecentRequests / StatsHeader /
Cleanup / CompressionToggle / ToastTray), move the API layer into
lib/, and split state into stores/.
Add a dedicated dashboard build (`build:dashboard-ui` + a separate
tsconfig.dashboard.json) so dashboard sources typecheck independently
of the proxy core, which previously broke the root `tsc` build.
The proxy used to expose ~20 behavior toggles (--no-compress,
--no-tools, --no-schemas, --no-reminders, --no-tool-results,
--history, --no-history, --history-keep-tail N, --history-min-prefix N,
--min-chars N, --min-reminder-chars N, --min-tool-result-chars N,
--cols N, --multi-col N, --no-track, --events-file PATH, --port N,
--upstream URL) plus matching env vars. Each one was a dead branch in
the common case and a configuration knob nobody had a principled
reason to pick a value for.
Replaced with: exactly one way to run the proxy. Every compression
mode on, every tuning parameter at its measured-best value, history
compression always active (was opt-in dead code). The only adjustable
surface is deployment concerns — where to listen, what to forward,
where to log — env-var only:
PORT default 47821
ANTHROPIC_UPSTREAM default https://api.anthropic.com
PIXELPIPE_LOG default ~/.pixelpipe/events.jsonl
CLI accepts only --help and --version. Anything else exits with
non-zero and a one-line error.
Notable behavior change:
- DEFAULTS.compressHistory flipped false → true. Variant-C history-
image compression now runs on every request (was opt-in via
--history / COMPRESS_HISTORY=1). The static-slab cache_control
placement is on the system image, not on the history-replacement
chain, so the published cache-topology risk does not apply.
Touched:
- src/node.ts: CliOpts → RuntimeConfig (3 fields). parseCli is now
~25 lines. printHelp reduced to env-var-only doc.
- src/core/transform.ts: DEFAULTS.compressHistory = true. Comment
updated.
- scripts/restart.sh: drops PROXY_ARGS array entirely. Port read
from PORT= env var. Unknown args rejected.
- tests/restart.test.sh: replaces flag-passthrough test with a
reject-unknown-args test. 4/4 pass.
- tests/history.test.ts: renames the "compressHistory:false (default)"
test to reflect the new always-on default; asserts the input-not-
mutated invariant remains.
- README.md: configuration table reduced to 3 env vars; restart
examples drop CLI flag passthrough.
Tests: 277/277. Typecheck + build clean. Restart script tests: 4/4.
Unifont glyphs are inherently 1-bit (every pixel is 0 or 255). Storing as
8-bit bytes wasted 7 bits per pixel.
Changes:
- scripts/gen-atlas.ts: emit ATLAS_PIXELS as bit-packed MSB-first. OFFSETS
now indexes bits not bytes. Per-cell paint thresholds R-channel at 128
defensively (Unifont is already 0/255).
- src/core/render.ts:blitGlyph: byte read replaced with bit extraction
(~3 extra ops per pixel; negligible). max() blending removed since bit
data is binary, no AA edges, no glyph overlap.
- src/core/atlas.ts: regenerated with the new format. Header comment
documents the bit-extraction formula.
- tests/render.test.ts: +1 structural assertion that ATLAS_PIXELS.byteLength
matches the bit-packed total.
Bundle size:
atlas.ts raw: 5.47 MB → 1.06 MB (5.2× shrink)
atlas.ts gzip: 1.55 MB → 479 KB (3.2× shrink)
dist gzipped: 1.57 MB → 488 KB (3.15× shrink, well under Workers
free-tier 1 MB cap)
Pre-deflate shrink is 8× (theoretical max). The 3.15× post-deflate
result reflects that deflate was already exploiting long runs of 0/255
in the 8-bit data; the bit-packed bytes are denser and less compressible.
Render output is byte-identical to pre-bit-pack (storage format change
only). 108/108 vitest, 4/4 shell tests, typecheck + build clean.
- Switch font: JetBrains Mono @ 15px → Unifont 16.0.04 @ 10px. Sparse
atlas with double-width EAW dispatch for CJK. Full BMP profile
(35,501 glyphs) covers Latin/Cyrillic/Greek/Hebrew/Arabic/CJK/Hangul
plus Letterlike, Misc Technical, Block Elements, Geometric Shapes,
Misc Symbols, Dingbats, Enclosed Alphanumerics, all box-drawing.
- Fix cell-height bug (was hardcoded 9; now probed from font metrics
via Math.ceil(maxAscent+maxDescent)). Previously clipped the top
2 rows off every CJK glyph since the original Unifont ship.
- Expand tabs to spaces with 4-column tab stops, EAW-aware. Was the
silent-drop source for 99.6% of dropped chars in production.
- Add dropped_codepoints_top telemetry (top 20 per event, only emitted
when drops > 0) so future coverage gaps surface in events.jsonl.
- Raise minToolResultChars 2000→5000 and minReminderChars 1000→2000
to stop net-losing tokens on small compressions, per ~2,500 tok/img
empirical measurement (N=33 cold-miss events).
- Fix dashboard per-image-cost formula: was pngBytes/375 (~190 tok),
now imageCount * 2500 (the measured empirical rate). Reduces the
inflated "tokens saved" headline to honest numbers.
- Schema-stub fix in compressSchemas path: preserveSchemaShell()
retains type / properties / required / enum / oneOf / anyOf / $ref /
numeric constraints recursively (depth 20), strips only descriptions
and metadata. Prevents 400 errors on first-tool-call requests.
- Capture full gzipped 4xx body + per-event req_body_sha8 for upstream
error diagnosis. Sidecar to ~/.pixelpipe/4xx-bodies/ when over 32 KB
inline cap. Workers-safe via CompressionStream + Web Crypto.
- scripts/restart.sh: pnpm-aware one-command kill+rebuild+start with
graceful SIGTERM→SIGKILL escalation, build-failure abort, port-in-use
precheck, --no-build flag for fast iteration. Shell-tested.
- Bundle 1.58 MB gzipped on Node. 91/91 vitest + 4/4 shell tests.
Project rename for the Show HN launch with framing:
'pixelpipe — what if Opus saw a UI instead of just append-only logs?'
Renamed everywhere:
- kebab-case 'claude-image-proxy' -> 'pixelpipe' (42 occurrences)
- snake_case 'claude_image_proxy' -> 'pixelpipe' (5 occurrences)
- 14 files touched: package.json, Cargo.toml, Cargo.lock, *.md,
bin/cli.js, scripts/install.js, src/proxy.py, src/rust/src/main.rs,
src/rust/examples/{render_sample,transform_only,diff_render}.rs,
src/zig/build.zig
Effects on build artifacts:
- npm package name -> 'pixelpipe'
- Rust binary name -> target/release/pixelpipe (was claude-image-proxy)
- Python cache dir -> ~/.cache/pixelpipe/ (was ~/.cache/claude-image-proxy/)
NOT YET DONE in this commit (Tier 2+3, handled in next commit):
- Repo on-disk directory still ~/Downloads/repos/claude-image-proxy/
- Cache dir on disk still ~/.cache/claude-image-proxy/ — Python proxy
currently writes here. Will be migrated alongside the running services
in a coordinated stop/move/restart sequence.
Validation: scripts/diff_transform.py still produces exactly 1 structural
diff (the PNG bytes, expected — different fonts Python/Menlo vs
Rust/JetBrains Mono). No regression from the rename.
Three bug fixes surfaced by scripts/diff_transform.py harness, which
synthesizes a realistic Claude Code request body and runs it through both
Python transform_request() and Rust transform(), then JSON-structurally
diffs the outputs.
Before these fixes, harness found:
- 2 structural diffs in the transformed body JSON
- 4+ TransformInfo divergences
After these fixes, harness finds:
- 1 structural diff: $.messages[0].content[1].source.data
(the base64 PNG, expected to differ — Menlo vs JetBrains Mono fonts)
- TransformInfo still differs on byte-vs-char counts (telemetry-only)
Fixes:
1. src/rust/src/transform.rs:93 — per-tool markdown header
was: '### Tool: {name}\n{desc}'
now: '#### Tool: {name}\n{desc}\n'
Matches proxy.py:230,233. Also restores the trailing newline that
Python emits between tool entries.
2. src/rust/src/transform.rs:123 — tool section markdown header
was: '\n\n# Tool Documentation\n\n'
now: '\n\n#### Tool Documentation\n\n'
Matches proxy.py:248.
3. src/rust/src/transform.rs:265 — preserve system field by default
was: always replaced system with billing_line OR remainder
now: only replaces if billing_line was stripped, otherwise leaves
the original system field untouched.
Matches proxy.py:417 which intentionally leaves system alone in the
default PLACEMENT="user" path 'so Anthropic still has guardrails'.
The image lives in messages[].content as a side-channel; system stays
as original text. This is the behavior our 95+ live Python requests
have validated against Anthropic's API.
4. src/rust/src/lib.rs — expose 'transform' module so harnesses and the
transform_only example can call transform() without going through HTTP.
Added:
- src/rust/examples/transform_only.rs — CLI binary that reads a body
from a file and writes the transformed body + TransformInfo as JSON.
- scripts/diff_transform.py — Python harness that calls both Python
transform_request() and the Rust transform_only binary, then runs a
structural JSON diff with field-by-field TransformInfo comparison.
Validation:
python3 scripts/diff_transform.py
# → 'found 1 structural diff'
# → $.messages[0].content[1].source.data (the PNG, expected)
Remaining known telemetry-only diffs (not blocking the swap):
- system_text_chars: Python counts Unicode chars, Rust counts UTF-8 bytes
- tool_text_added: same UTF-8 issue
- expected_image_tokens: ~30% higher in Rust due to ab_glyph 4px cell
vs PIL 3px cell — Rust images are 33% wider for the same text. Rust
PNG bytes are still smaller overall because of the tight-bound height
(which Python also has now, after the previous baseline commit).
- placement, png_sha8 fields missing from Rust TransformInfo
- min_chars threshold uses bytes (Rust) vs chars (Python)
These can be addressed later for full telemetry parity but the
upstream-visible behavior is byte-equivalent.
src/proxy.py:125 was computing image height as
tallest = max(lines_per_col, last_col_lines) if c_needed == 1 else lines_per_col
The max(lines_per_col, ...) made every single-column render pad to the
full MAX_EDGE=1568 canvas height regardless of content, wasting ~99% of
the image-token budget for small prompts.
Fix: tight-bound the single-column case.
tallest = max(1, last_col_lines) if c_needed == 1 else lines_per_col
Multi-column (c_needed > 1) is unchanged — all earlier columns must be
lines_per_col tall to fit them, so the image must be too.
Measured impact (scripts/visual_compare.py):
sample before after change
----------- ------------ ------------ -----------
17 chars 241x1568 241x14 -99% pixels
176 chars 241x1568 241x42 -97% pixels
885 chars 241x1568 241x315 -80% pixels
Verified edge cases hold:
- empty/short text: still gated by MIN_COMPRESS_CHARS
- 5000-char single line: 241x441 (63 wrapped lines, tight)
- 80-char boundary: 241x14 (2 lines, tight)
- 500-line multi-column: 731x1568 (unchanged, correctly padded)
- 20KB realistic system prompt: 68.5% savings (matches existing 65-73%)
Added scripts/visual_compare.py to inspect Python vs Rust renderings
side-by-side with labels and dimensions.
This is the immediate win that's independent of the Rust rewrite — every
proxied request gets fewer image tokens starting at the next proxy restart.
Functional reimplementation in Rust with the same render_chunks/transform
public surface as src/proxy.py. Compiles clean on darwin-arm64, smoke-
tested but NOT YET battle-tested against real Claude Code sessions.
Layout:
src/rust/
Cargo.toml hyper + tokio + reqwest + ab_glyph + png + clap
Cargo.lock committed (application crate, deterministic builds)
src/main.rs clap CLI matching bin/cli.js flags
src/lib.rs module roots
src/font.rs ab_glyph rasterization of bundled JetBrains Mono
src/render.rs newspaper-column text -> PNG (matches Python algo)
src/transform.rs request body transformation (system prompt -> image)
src/proxy.rs hyper HTTP server, upstream forwarding
src/stats.rs persisted savings counters mirroring proxy.py
assets/JetBrainsMono-Regular.ttf OFL-licensed, legally embeddable
examples/render_sample.rs smoke test: render fibonacci snippet
examples/diff_render.rs diff harness companion (paired with
scripts/diff_render.py)
Diff harness:
scripts/diff_render.py feeds same text through Python and Rust
render_chunks, decodes both PNGs, compares
pixel-by-pixel. First run found two divergences:
1. Rust font.rs:43 uses ab_glyph h_advance which returns ~3.4px ceiled
to 4 for Menlo-5pt 'M'; PIL's getlength('M') returns 3.0 exactly.
Every Rust column is 33% wider than Python's.
2. Python proxy.py:125 pads every single-column image to MAX_EDGE=1568
height regardless of content (already noted in baseline commit).
Neither is fixed yet — surfacing the divergences before any swap. Next:
visual inspect both PNGs to confirm Rust output is at least OCR-readable,
then decide whether to fix bug-for-bug compat or correct both sides.
bin/cli.js still spawns Python; this commit only adds the Rust tree, it
does NOT change runtime behavior. The live proxy at :47821 is unaffected.
Token-saving HTTP proxy for Claude Code that renders system prompt + tools
as 5pt Menlo monospace images. Achieves 65-73% token reduction with 100%
reasoning quality preserved on Opus 4.7.
Production state at this commit:
- src/proxy.py: 972 lines, battle-tested with 46+ real Claude Code sessions
observed (~551k tokens saved, ~$8.27 in stats.json as of commit time)
- bin/cli.js: Node wrapper that spawns Python proxy on port 47821
- scripts/gen_atlas.py: generates the bundled Menlo 5pt glyph atlas
- scripts/install.js: postinstall — verifies Python + Pillow + httpx
- src/zig/: earlier Zig 0.16 renderer (kept for reference, not built)
- CLAUDE.md, HANDOFF.md: contributor notes
- package.json: npm entry point, version 0.1.0
Known issue (deferred for separate fix):
src/proxy.py:125 — `tallest = max(lines_per_col, last_col_lines) if
c_needed == 1 else lines_per_col` pads every single-column image to
full MAX_EDGE=1568 height regardless of content, wasting image-token
budget for small inputs. Tight bounding would improve savings further.
This is the rollback point. Any subsequent changes (Rust port, Python
fixes, etc.) build on this proven baseline.
teamchong