Readiness Audit

Upstream-readiness audit

Standing structure for offering fork work back to chilli-axe/mpc-autofill one self-contained chunk at a time, without ever sending an omnibus. This document is a survey, not an action — nothing here has touched upstream's repo. Phase 2 (cutting actual branches) happens only after the owner picks specific chunks off the ladder below.

Phase 2 status (owner decision, 2026-07-18)

Upstreaming continues at minimal investment — this audit satisfies docs/infrastructure.md's check-in requirement, and the frontend-direction question (whether chilli-axe is actually dropping the Node.js frontend) goes to the maintainer directly via a P.S. on an unrelated upcoming message, rather than being speculated on here. Full Phase-2 scope waits on that answer.

One branch cut now, as pattern-proof: upstream-feat-local-file-source (Tier 1 #2 below), chosen for best survival odds if the frontend answer turns out to matter — it's 100% backend, no frontend surface at all. Pushed to origin (this fork) at commit 93874645, cut from upstream/master at c3d10253. Pre-commit (ruff/isort/black/mypy) green in the extracted context; test coverage hand-verified where the sandbox's missing Docker/Postgres/ES made the real test suite uncollectable. Draft PR description at drafts/upstream-feat-local-file-source.md. Not opened anywhere — sits ready until the owner sends it.

Card DOM API (Tier 1 #1) and the dead-image/error-states pairing (Tier 1 #4+#5) are deferred, not dropped — next up once the frontend question is answered, since both are frontend chunks and their value depends on there still being a Node.js frontend for upstream to accept changes into.

CI added for the ladder, 2026-07-18 (while dormant, per a separate request): .github/workflows/upstream-branch-verification.yml and upstream-drift-monitor.yml, detection-only, described in full in conventions.md's "CI for the ladder" section. Neither fires for real until this branch merges to master (GitHub only schedules workflows that exist on the default branch) — docs/upstreaming/drift-log.md is seeded by hand in the meantime with the same computation the workflow will run.

0. Method and ground truth

git diff upstream/master origin/master (two-dot, tree-level) is the only diff form that works here — there is no merge-base between the upstream remote (chilli-axe/mpc-autofill) and this fork's origin history as normally cloned, because the drives.csv history rewrite (see docs/infrastructure.md) scrubbed a leaked-secrets range. A three-dot diff or A..B commit range silently returns nonsense (or nothing) against that gap.

Two gotchas hit while producing this audit, both worth carrying forward:

• Shallow-clone false alarm. A shallow clone (the default for this session) makes the merge-base gap look total — git cat-file -t on every SHA in docs/upstreaming/vote-system.md fails, git merge-base returns nothing, and it reads exactly like the history-rewrite incident happened again. It didn't. git fetch --unshallow origin (fetching either remote unshallows the shared object store) restores the real picture: merge-base is 3c717d2a (matching vote-system.md's 2026-07-13 finding exactly), every historical SHA resolves, and upstream/master has moved exactly 2 commits past that point as of 2026-07-18. Any future session doing extraction work must git fetch --unshallow before trusting a "no merge-base" or "SHA not found" result as real — it's much more likely to be this artifact than a second history-rewrite incident.
• upstream/master genuinely does move. 2 commits in 5 days (2026-07-13 → 2026-07-18) at the observed rate, mixed dependabot and human PRs. Re-verify merge-base and re-diff the target file set immediately before cutting or updating any extraction branch — don't trust a stale check.

The one PR of ours already merged upstream: #467, "Fix toSearchable to not strip mid-string 'the'" (completes backend PR #460), merged 2026-07-18 by maintainer Nicholas de Paola. Full characterization in §6 / conventions.md — it's the house style every upstream/* branch should match.

Standing risk, foregrounded per docs/infrastructure.md: upstreaming is currently deprioritized — chilli-axe has signaled plans to drop the Node.js frontend, which could waste further upstreaming effort. This audit is the "checking in first" the doc asks for; it does not override it. Nothing below should be sent without the owner re-confirming that's still worth doing, chunk by chunk.

1. Full chunk decomposition

Three independent passes: backend (MPCAutofill/, schemas/), frontend (frontend/), and everything else (CI, docker/, image-cdn/, desktop-tool/, root config) + conventions mining. Total diff size: MPCAutofill/ +20,058/−439 (105 files), schemas/ +584/−2 (44 files, all net-new), frontend/ +14,906/−2,594 (150 files), everything else +6,352/−61 (38 files). Migrations 0001–0049 are byte-identical to upstream; everything from 0050 on (0050–0064, 15 migrations) is fork-only.

Legend — Value: (a) useful to every instance, (b) useful to forks like us, (c) ours-only. Risk: extraction/entanglement risk if cut into its own branch.

1.1 Backend (MPCAutofill/, schemas/)

Provenance column added per the owner's license-provenance amendment (§9) — own-work (net-new fork code, no upstream equivalent) or upstream-GPL3 (a modification/extension of an existing upstream file, same license, same repo tree — not a third-party import). See §9 for the one-time external-origin sweep this ladder itself is exempt from (none of these 11 chunks involve code from outside the fork/upstream tree).

Chunk	What	LOC	Value	Risk	Depends on	Provenance
A. Printing-tag vote system (core)	Weighted-consensus engine (AbstractWeightedVote, VoteSource) + CanonicalPrintingMetadata/CardPrintingTag, printing-candidate search, ES re-rank hook	~700 (migrations 0050–0051)	(a)	Low	none — foundation	own-work
B. Artist + tag weighted voting, unified queue	Extends A to artist/tag attributes, 2/voteQueue/	~1,300 (migrations 0052–0055, 0057)	(a)	Medium	A	own-work
C. Tag taxonomy (Stage 3)	Seeded Tag rows + fuzzy filename matching, display_name split	~500 (migration 0056)	(b)	Low	none (functional dep on B)	upstream-GPL3 (extends upstream's existing Tag model)
D. Unified question feed	2/questionFeed/, single prioritized review stream replacing the 3-tab switcher	~600	(a)	Medium	A, B, F	own-work
E. Moderation layer	Discord OAuth, privileged-vote co-sign gate, CardReport, Reports/Drives admin queue	~1,300 (migrations 0057–0059)	(b), mechanism only	Medium-high	A, B, C	own-work
F. Deductive printing-tag backfill	Logic-only vote casting (D1/D2 tiers) for logically-entailed printings	~600	(a)	Low	A, C	own-work
G. Local OCR/phash identification pilot	Tesseract + perceptual-hash + fallback engines, run-cohort revocability	~6,700 (migrations 0060–0064)	(a) with caveats — pilot-status, fork-tuned constants	High	A, F, I	own-work (uses the real pytesseract/imagehash PyPI deps, not copied algorithm code — see §9)
H. LOCAL_FILE source type	Real implementation of upstream's already-anticipated stub; local-disk cataloging + path-traversal-safe image serving	~320	(a)	Low	none — most self-contained chunk in the diff	upstream-GPL3 (completes a stub upstream's own schema/enum already defined)
I. Image-CDN backend fetch helper	image_cdn_fetch.py, server-side full-res fetch for OCR/hashing	~77	(c) as written	Medium	Worker/R2 infra (out of scope)	own-work
J. Decklist printing-aware line formatting	format_decklist_line() appends (SET) NUM when the import API gave printing data	~50 (entangled in a 107-line file diff)	(a)	Low, but needs hunk-split	none	upstream-GPL3 (edits an existing upstream file)
K. Ours-only operational settings	Sentry removal, CORS branding, Discord/session-cookie env wiring	interleaved in settings.py	(c)	N/A — strip, don't port	—	upstream-GPL3 (edits upstream's existing settings.py)

Full per-chunk detail (files, tests, exact dependency chains, entanglement notes) is in the backend research pass; the table above is the actionable summary. One correction to the original brief: "PDF layout backend support" and "XML 2.0 backend support" do not exist — both are 100% frontend-only (confirmed: zero xml matches anywhere in MPCAutofill/'s diff).

1.2 Frontend (frontend/)

Same Provenance convention as §1.1. IV.5 is the one row that's genuinely mixed — the ordering-tab logic is own-work, but its flag icon assets are real external-origin content, already found and fully triaged by §9's sweep (not a new finding this table introduces).

Chunk	What	LOC	Value	Risk	Depends on	Provenance
I.1 PDF layout extraction (computeLayout)	Pure, side-effect-free page-layout math pulled out of render components	336, both new files	(a)	Very low	none	own-work
I.2 WYSIWYG page preview	Canvas preview using I.1, no real PDF render needed	541 + pdfjs-dist build step	(a)	Low	I.1	own-work
I.3 PDF dead-image blocking	Blocks/warns instead of silently shipping blank cards on a failed image fetch	~739	(a)	Low	none	upstream-GPL3 (modifies existing image-fetch/render logic)
I.4 XML 2.0 export + decklist round-trip	Versioned, backward-compatible XML with optional printing data; stripFoilMarker import fix	~360	split (a)/(b)	Low (format/foil-fix) / Medium (suffix payload)	suffix payload needs A/D	upstream-GPL3 (extends upstream's existing XML export)
II.1 Grid-selector UX/a11y pass	Keyboard nav, modal autofocus fix, mobile filters default	285	(a)	Very low	none	upstream-GPL3 (modifies the existing grid-selector component)
II.2 Card image error/loading states	"Still loading…" hint, styled error placeholder replacing a harsh black 404 PNG — the display-side of dead-link handling	404	(a)	Very low	none	upstream-GPL3 (modifies the existing Card component)
II.3 Card DOM API	data-card-* attributes + mpc:card-selected event, additive/generic	~300	(a)	Very low	none — already flagged "pending upstream" in fork memory	own-work
II.4 DeckbuilderConfirmAffordance	In-context printing-confirm badge in the editor	650	(b)	High	IV.3, I.4, A	own-work
II.5 General UI/mobile/a11y polish	Mobile stacking, scroll-chain fix, a11y sweep	~424	(a)	Low (verify Navbar.tsx isolation)	none	upstream-GPL3 (modifies existing components)
III.1–III.8 "What's That Card?" frontend	QuestionFeed, PrintingTagPicker, attribute voting/chips, reporting, moderation UI, /whatsthat page	~6,300	(b)/(c) mixed	High	A, B, C, D, E	own-work
III.2 questionFeed count-semantics fix	The specifically-requested candidate — confirmed real historically (a0e2aa08), but fully subsumed into III.1's current 970-line file, not separable today	n/a now	(b)/(c), inherits III.1	N/A — would need reconstruction from git history if pursued alone	III.1	own-work
IV.1 Google Drive "Save PDF to Drive"	Write-scoped OAuth flow, independent of the existing read-only picker	174	(a)	Very low	none	own-work
IV.2 Search filters	Mature-content toggle (generic) + resolved-attribute filters (needs backend)	511	split (a)/(b)	Low / Medium	ResolvedAttributeFilter needs A/D	upstream-GPL3 (modifies existing filter UI)
IV.3 API error surfacing + toasts	Real backend error messages + friendly 429 handling	250	(a)	Low	none	upstream-GPL3 (modifies existing API-error handling)
IV.4 Keyrune set-icon rendering	Real MTG expansion-symbol glyphs via icon font	~115	(a)	Very low	none	own-work (rendering code only — draws on the real keyrune npm package as a normal, gitignored install-time dependency; not the same thing as §9's finding of a second, separately-vendored copy of keyrune's font+license in the backend OCR pilot)
IV.5 Print-export ordering tabs + flags	NotMPC/PringlePrints tabs, vendored flag SVGs	227	(c) unambiguously	High (vendor content)	none	own-work (tab logic) + external (flag SVGs: lipis/flag-icons, MIT — §9 finding, already attributed in-repo)
IV.6 Telemetry/Sentry removal	Deletes fork's own error-tracking opt-out	−64	(c)	None to extract	—	upstream-GPL3 (removes upstream's own integration)
IV.7 Branding & site identity	About page, logo, footer, nav copy	~148	(c)	N/A	—	own-work (original identity content; no external-origin assets found here per §9)
IV.8 Support-modal removal	Deletes upstream's donate/support-developer modals	−180	(c)	None	—	upstream-GPL3 (removes upstream's own modals)
IV.9 Build/tooling & test-infra	Mostly ours-only config; one candidate: msw+playwright patch	~110 + lockfile	mostly (c), one (a)	Low	verify upstream has same dep pair first	upstream-GPL3 (modifies existing config)

1.3 CI / tooling / infra (everything outside frontend/, MPCAutofill/, schemas/)

cloudflare-static-site/, github-release-reverse-proxy/, and every root config file (readme.md, pyproject.toml, mypy.ini, .prettierignore, .python-version, uv.lock) are byte-identical to upstream — zero drift, nothing to reconcile there. All branding lives in frontend/.

Chunk	What	Value	Risk	Provenance
restart: unless-stopped on all 5 compose services	Host-reboot resilience, live-verified with a real reboot test	(a)	Very low	upstream-GPL3 (edits existing compose files)
Postgres/ES bound to 127.0.0.1 not 0.0.0.0	Security hardening, stops exposing DB/search ports to the internet	(a)	Very low	upstream-GPL3 (edits existing compose files)
nginx Host/X-Forwarded-Proto header fix	Fixes nginx's proxy_pass defaulting Host to the upstream container's own name, breaking absolute-URL construction behind a reverse proxy	(a) (the 2-line header fix specifically)	Very low	upstream-GPL3 (edits existing nginx config)
image-cdn full-tier rate limiter + CORS fix	The "client-side rate pacer" from the original brief — it's a Cloudflare Worker chunk in image-cdn/, not frontend/. Adds real rate limiting + an intentional (not accidental) CORS header for lh4.googleusercontent.com full-res fetches	(a)	Low	own-work
desktop-tool PIL.Image → PILImage TYPE_CHECKING rename	Avoids an import-shadowing footgun	(a)	Trivial	upstream-GPL3 (edits an existing upstream file)
.dockerignore	Stops uploading the whole repo (incl. gigabyte+ node_modules) as Docker build context	(a), minus one .claude line	Low	upstream-GPL3 (edits an existing upstream file)
CI mypy numpy-pin lesson	"An unpinned transitive dep can resolve differently in CI's mypy sandbox than local dev" — a portable insight, not a standalone diff	(a) as a lesson only	N/A alone	N/A — no diff, nothing to classify
GIT_SHA build-arg baking + staleness gate	Detects a deployed image running stale migrations	(b)	Medium — split across Docker + backend	own-work
entrypoint.sh: always migrate, drop blocking first-boot catalog bootstrap	Real behavior change — a fresh instance no longer auto-populates on first boot	(b)	Medium-high, must be opt-in not a silent default flip	upstream-GPL3 (edits upstream's existing entrypoint.sh)
GA/Sentry removal from CI, GH Pages deploy pipeline, docker-compose.prod.yml env branding, test-backend dropped from build-frontend's needs	Fork hosting/telemetry choices	(c)	N/A	upstream-GPL3 (edits existing upstream CI/deploy files)

2. Dependency graph

graph TD
    A["A: Printing-tag vote<br/>system (core)"] --> B["B: Artist/tag voting<br/>+ unified queue"]
    C["C: Tag taxonomy"] -.functional.-> B
    A --> F["F: Deductive backfill"]
    C -.functional.-> F
    B --> D["D: Question feed"]
    F --> D
    A --> E["E: Moderation layer"]
    B --> E
    C --> E
    A --> G["G: Local OCR/phash pilot"]
    F --> G
    I["I: image_cdn_fetch"] --> G
    H["H: LOCAL_FILE source"] -.optional hook.-> I

    A --> III["III.1-8: What's That Card?<br/>frontend cluster"]
    B --> III
    C --> III
    D --> III
    E --> III

    IV3["IV.3: API error surfacing"] --> II4["II.4: DeckbuilderConfirmAffordance"]
    I4["I.4: XML 2.0 (suffix payload)"] --> II4
    A --> II4
    D --> II4

    A --> IV2b["IV.2b: ResolvedAttributeFilter"]
    D --> IV2b

    II3["II.3: Card DOM API"] -.sibling helper, no dep.-> III

    I1["I.1: PDF layout<br/>(computeLayout)"] --> I2["I.2: WYSIWYG preview"]

    classDef ready fill:#2d6a4f,color:#fff;
    classDef risky fill:#9d0208,color:#fff;
    class II3,H,I1,I2,II2,II1,IV1,IV4,I3 ready
    class G,III risky

Loading

Roots with zero dependency on any other fork-only code (green in the graph): Card DOM API (II.3), LOCAL_FILE source (H), PDF layout extraction (I.1), PDF dead-image blocking (I.3), grid-selector pass (II.1), card image error states (II.2), Google Drive Save-to-Drive (IV.1), Keyrune icons (IV.4), all the CI/tooling one-liners. These are the ones a maintainer can review with zero context on the rest of the fork.

Chunk A is the true foundation of everything "What's That Card?"-shaped (B through G, III.1–8 all trace back to it) — proposing it is the highest-leverage single move if the vote system is ever pitched at all, but it's also the biggest single non-trivial-review-size chunk in that family (~700 LOC plus the search/ES hooks it wires into).

3. The ladder

Ranked by (upstream value × extraction ease). Tier 1 chunks need no other fork-only code, have no fork branding, and are small enough to review as one PR each — these are what Phase 2 should draw from.

Tier 1 — ready now, near-zero prep

1. Card DOM API (frontend II.3) — additive, generic, zero deps, already informally flagged as "pending upstream" in this fork's own working notes before this audit even started.
2. LOCAL_FILE source type (backend H) — completes a stub upstream's own schema/enum already anticipated; the most self-contained chunk in the whole diff; 17 tests need no network/credentials.
3. PDF layout extraction / computeLayout (frontend I.1) — pure refactor-for-testability, two new files, nothing else touched.
4. Card image error/loading states (frontend II.2) — the display half of dead-link handling; replaces a harsh black 404 PNG with a real placeholder + slow-load hint.
5. PDF dead-image blocking (frontend I.3) — a real silent-data-loss bug fix (blank cards shipped to a print vendor with no warning); strong "why this matters" story for a reviewer.
6. Grid-selector UX/a11y pass (frontend II.1) — keyboard nav + autofocus + mobile-default fixes, all correctness bugs.
7. Google Drive "Save PDF to Drive" (frontend IV.1) — a generically valuable capability extension to a feature upstream already has.
8. Keyrune set-icon rendering (frontend IV.4) — real MTG set-symbol glyphs, zero fork data shape required.
9. stripFoilMarker decklist-import fix (embedded in frontend I.4, needs extracting from the larger XML-2.0 commit) — tiny, generic bug fix for foiled-card collector-number parsing.
10. Docker/infra one-liners: restart: unless-stopped, Postgres/ES bound to 127.0.0.1, the nginx Host/X-Forwarded-Proto fix, desktop-tool's PIL.Image rename. All trivial, all universal.
11. image-cdn full-tier rate limiter (the actual "rate pacer" — it's in image-cdn/, not frontend/, correcting the original brief) — self-contained Worker module + 6 tests, fixes an accidental (not intentional) CORS pass-through as a side effect.

Tier 2 — real value, moderate prep

• WYSIWYG PDF preview (I.2) — needs its pdfjs-dist/postinstall build step to travel with it.
• API error surfacing + friendly 429 toasts (IV.3).
• General UI/mobile/a11y polish (II.5) — isolate Navbar.tsx's branding lines first.
• .dockerignore — strip the one .claude reference.
• Decklist printing-aware line formatting (backend J) — clean content, needs hand-splitting out of a file that also carries two unrelated changes.
• Mature-content filter toggle only (IV.2, not the resolved-attribute half) — pure UI surfacing of an existing setting.
• msw+playwright patch (IV.9) — verify upstream's package.json actually has the same dependency pair before proposing.
• XML 2.0 format mechanism, minus the canonical-printing-suffix payload (I.4 partial) — versioned/backward-compatible export format on its own merits.

Tier 3 — high value, needs a real feature-sized pitch

• Printing-tag vote system: Chunk A (+ optionally B, D) — the single most upstream-pitchable big idea in this fork (community disambiguation of which Scryfall printing a catalog image depicts), but it's feature-sized, not quick-win-shaped, and its frontend half (Cluster III) is ~6,300 LOC that doesn't work without it. This is docs/upstreaming/vote-system.md's territory — see §5 below for that doc's current accuracy.
• Moderation layer (E) — the mechanism (privileged-vote co-sign, pluggable moderator grant) generalizes; the Discord-specific wiring doesn't, and would need reframing as provider-agnostic OAuth first.
• GIT_SHA build-arg + staleness gate (CI + backend) — needs the Docker and backend halves coordinated in one pitch.
• entrypoint.sh migrate-always change — a real behavior change (drops first-boot auto-catalog-population); must be pitched as opt-in, not a silent default flip, or it breaks upstream's documented quick-start experience.

Tier 4 — not upstream-pitchable (ours-only, catalog and skip)

Branding (About page, logo, footer, nav copy), Discord OAuth specifics, PringlePrints/NotMPC ordering tabs (vendor-specific business content), Sentry/GA telemetry removal, support-modal removal, the GitHub Pages deploy pipeline, docker-compose.prod.yml env/branding additions, CORS_ALLOWED_ORIGINS swap, dropping test-backend from CI (fork is missing upstream's secrets, not a bug).

Tier 5 — too large/risky for any near-term PR

Local OCR/phash identification pilot (backend G, ~6,700 lines). Real and reusable in mechanism (never-resolve-alone gate, checkpointing, run-cohort revocability via PilotRunLedger), but explicitly pilot-status: ~12.8-day single-process full-catalog runtime, tuning constants (fetch DPI, crop boxes, phash thresholds) empirically derived from this fork's own small sample images, a RunPython data migration splitting production vote data (0060), and the heaviest shared-file entanglement of any chunk. Would need splitting into several independently-reviewable PRs (OCR engine / phash engine / fallback engine / orchestration) and a re-validation pass against a different catalog's images before it's honestly presentable — not a Phase-2 candidate.

Tier 6 — blocked on a precondition that doesn't exist yet

Federation verdict-exchange consumer component (subscriber-side: verdict table, phash tooling, signature verification, agreement badge — docs/federation-v1.md). Not large or risky like Tier 5 — the opposite, actually: deliberately dependency-free, no vote/consensus/moderation stack required, the single most upstream-shaped idea in the whole federation program. It sits here instead of Tier 1 for a different reason than size or entanglement: there's no live peer to subscribe to yet, and this fork's own v1 posture is publisher-only (see federation-v1.md's "Participation modes"), so there's nothing real to demo or extract against. Revisit once federation has an actual second instance on the other end — not before, and not on a schedule.

4. Candidates from the original brief — verified, corrected, or dropped

• questionFeed count semantics — real (fixed a0e2aa08, backend get_remaining_estimate()/QuestionFeedCounts), but not separable in the current tree: fully absorbed into QuestionFeed.tsx's current 970-line state. Demoted off the ladder; would need reconstruction from git history if pursued as a standalone fix, and only makes sense bundled with a Chunk D pitch anyway (question feed doesn't exist upstream to patch).
• CI/tooling hygiene fixes — confirmed, several genuinely good ones found beyond what the brief named (restart policy, port binding, nginx header fix, PIL.Image rename, .dockerignore, the mypy-numpy-pin lesson).
• Dead-link handling — confirmed real and split cleanly into a frontend display half (II.2) and a PDF-export half (I.3), both Tier 1.
• PDF layout extraction (computeLayout) — confirmed, Tier 1.
• Client-side rate pacer — does not exist in frontend/; the actual feature is the image-cdn Worker's rate limiter (image-cdn/, Cloudflare Workers code, not the Next.js app). Real and Tier 1, just mis-scoped in the original ask.
• XML 2.0 (+ import round-trip) — confirmed, real, splits into a generic format mechanism (Tier 2) and a fork-dependent payload (bundled with the vote system, Tier 3).
• Not previously on the ladder, found here: Card DOM API, LOCAL_FILE source type, Google Drive Save-to-Drive, Keyrune set-icon rendering, the Docker/nginx one-liners, and stripFoilMarker — several of these (Card DOM API, LOCAL_FILE) are arguably stronger candidates than anything on the original list.

5. docs/upstreaming/vote-system.md — currency check

Verified independently against current origin/master: accurate for what it says it covers (the ordered commit list, the PrintingTagQueue.tsx/printingQueue.tsx starburst-entanglement warning, the fork-content check) but materially incomplete as "the vote system" now means on current master — it predates:

• Chunk E (moderation layer) entirely (migrations 0057–0059 postdate its last-covered migration, 0055).
• Chunk D (question feed) — the doc still describes 2/voteQueue/ (Chunk B) as the redesign's endpoint; 2/questionFeed/ has since superseded it as the primary review surface.
• Chunks F and G (~7,300 combined lines: deductive backfill + the local OCR/phash pilot) — not mentioned at all.
• Its own §5 re-verification command (git merge-base upstream/master origin/master should show 0 commits ahead) needs the two-dot-diff method substituted for the range-diff it suggests, and the shallow-clone caveat from §0 above applied before trusting the result.
• Its specific cherry-pick recipe for PrintingTagQueue.tsx now targets a file that no longer exists — that logic was redistributed into cardPanel.tsx/whatsthat.tsx/QuestionFeed.tsx during the queue redesign. The doc's warning (don't cherry-pick that file's history commit-by-commit) is still directionally correct; its recipe needs redoing against the new files if ever acted on.

Recommendation: keep the doc as-is for the slice it accurately covers (Chunks A/B), but add a header note pointing here for anything past 2026-07-13, so a future reader doesn't assume it's the complete picture.

6. Conventions

Full write-up in docs/upstreaming/conventions.md. Headline findings:

• PR #467 (ours, merged) is one commit, plain imperative title, root-cause explanation + concrete before/after example in the body, references the completed companion PR (#460) by number, updates its test in the same commit. No conventional-commits prefix. This is the template to match.
• Upstream has no squash-merge policy and no enforced commit prefix — PR size is highly variable (2-file fixes to 3,000+-line overhauls), but every sampled PR (13 non-dependabot merges inspected) shipped test-file changes alongside the behavior change. None shipped without tests.
• PR bodies are hand-written, not AI-generated, per the maintainer's explicit ask across all 5 of this fork's upstream PRs so far — the Co-Authored-By: Claude Sonnet 5 commit trailer is the accepted AI-assistance disclosure, not PR body text.
• Full-stack features are commonly split into sibling backend/frontend PRs (e.g. #441/#442, merged ~3 hours apart) rather than one combined PR — worth replicating for any full-stack fork feature.
• Tool/hook versions in .pre-commit-config.yaml are already identical between fork and upstream — no reconciliation needed there. The only drift is the mypy hook's additional_dependencies pin list, which should carry only the pins a given extraction branch's own feature needs, and must not silently drop sentry-sdk unless the same PR is also proposing to remove upstream's own telemetry.

7. Branch architecture proposal

Tracking: keep the existing upstream remote (https://github.com/chilli-axe/mpc-autofill.git), fetched on demand (git fetch upstream master) rather than on a fixed schedule — chunks sit ready-and-waiting until the owner personally sends one, so there's no value in syncing more often than "right before cutting or updating a branch." Optionally mirror it as a local upstream-master branch (git branch -f upstream-master upstream/master after each fetch) purely for discoverability in git branch/git log --graph output; not load-bearing.

Per-chunk branches: this fork already has a naming convention in active use — upstream-fix-frontend-searchable-the, upstream-fix-image-cdn-cors, upstream-fix-pdf-canvas-preview, upstream-fix-pdf-eager-wasm-load, upstream-fix-pdf-thumbnail-worker-route all exist as branches on origin today. Extend it rather than replace it: upstream-fix-<slug> for bug fixes (as now), upstream-feat-<slug> for net-new capability chunks (e.g. upstream-feat-local-file-source, upstream-feat-card-dom-api, upstream-feat-save-pdf-to-drive).

Cutting a branch: per docs/infrastructure.md's existing workflow — a separate git worktree add <path> upstream/master -b <branch>, never a plain checkout in the main tree (keeps the fork's 40+ fork-specific commits from ever being reachable in the same working copy as upstream history). Cherry-pick the specific commit(s) when the original message ports cleanly; hand-reapply against upstream's current tree when it doesn't (references "our fork"/"our master", etc. — exactly the #467 precedent).

Before every push, not just the first cut: git fetch upstream master, re-run git merge-base upstream/master origin/master (unshallow first if needed — §0), git diff upstream/master <branch> to confirm the branch contains nothing but the intended change, rebase onto the new tip if it moved, re-run pre-commit run --all-files plus whichever upstream test suite(s) the change touches.

Maintenance cost: observed drift is low-frequency for human-authored, review-relevant changes — 2 commits in the 5 days between vote-system.md's last check and this one, and upstream's own recent-PR sample skews heavily toward dependabot bumps that rarely touch the same files a fork extraction would. Realistic cadence: check immediately before cutting a new branch, and again immediately before opening/updating a PR for one already cut — not a standing sync job.

8. What Phase 2 drew from — decided, see top of doc

Superseded by the owner's actual 2026-07-18 decision, recorded at the top of this document ("Phase 2 status"): one branch cut (upstream-feat-local-file-source), Card DOM API and the dead-image/ error-states pairing deferred pending the maintainer's frontend-direction answer. The original pre-decision reasoning (LOCAL_FILE source's zero-dependency, backend-only shape gave it the best survival odds regardless of how that answer lands) is preserved here since it's why that specific chunk was picked first among Tier 1's near-equally-ready options.

9. License provenance (owner amendment, 2026-07-19)

Every row across §1.1–1.3's three tables now carries a Provenance column: own-work (net-new fork code) or upstream-GPL3 (a modification of an existing upstream file — same repo tree, same license, not a third-party import). 41 rows total (11 backend + 20 frontend + 10 CI/tooling), not the 27 the commission estimated — stated plainly rather than force-fit to match; every row was individually classified from its own already-recorded "What" description, not independently re-diffed line-by-line (that would be its own multi-hour pass — flag any misclassification for correction).

Uniform, as expected, with exactly one flagged exception: no ladder chunk involves code copied in from outside the fork/upstream tree — IV.5 (print-export flag icons) is the one row that's genuinely mixed, and that's a pre-existing, already-attributed finding (the tab logic is own-work; the flag SVG assets are lipis/flag-icons, MIT), not a new problem this pass introduced.

A separate, one-time sweep of the WHOLE repo (not just these 41 ladder rows — everything under MPCAutofill/, frontend/, schemas/, image-cdn/, desktop-tool/, cloudflare-static-site/, github-release-reverse-proxy/, docker/, .github/) for vendored files, copied snippets, and dependency-adjacent copies found 4 real external-origin items — not "expected clean, confirmed clean": two of the four are missing full license-notice compliance, a real, previously-unnoticed gap this pass closes. Full findings, the PROTECTED CORE policy, the absorption protocol, and the disclosure mechanics this amendment also ships are in the new companion doc, license-provenance.md — kept separate from this file since it's forward-looking policy + a point-in-time sweep result, not chunk-decomposition data, matching how conventions.md already sits alongside this doc for a related-but-distinct concern.