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Agent handoff — cross-machine continuity

Last updated: 2026-07-22, with locals-query processing (#134) implemented and awaiting review, after modeline language detection (#132), Vterm Stage 2 (#130), and mode system wiring (#129/#131) landed on main. Vterm Stage 3 is not implemented. This file is the bridge between development machines. If you are an agent reading this on a fresh clone: this document plus the docs/*-framing.md files ARE your memory. Read this fully before taking on work, seed your persistent memory from it, and update this file (and commit it) whenever project state changes materially — the next machine reads it the way you just did.

For volatile branches, checkpoints, verification, and recovery commands, read docs/active-work.md immediately after this file.

1. Where the project stands (2026-07-22)

  • main @ 8bd8298 (landed-state handoff #133; latest runtime merge 1dd47fc, modeline detection #132), protocol v18 (SUPPORTED=[6..18]; v16 = ThemeFacts, v17 = FontFacts, v18 = StatuslineSegments).
  • Config registry LANDED — #127 (docs/config-registry-framing.md rev 3; merge 2e37c04; two review rounds). pmacs.config is the typed, introspectable options registry the backlog ranked first, and it closes the "config-registry-blocked" deferrals below. It was built as a PARALLEL LANE alongside vterm in a sibling worktree; the files were assigned per-lane up front and the rebase had zero conflicts.
    • Third registry beside CommandRegistry/HookRegistry (src/config_registry.rs), same R42/R50/duplicate-rejection/ SourceLocation vocabulary; Lua surface in src/lua_bindings/config.rs. No protocol change (still v18) and ZERO changes to src/editor.rs.
    • An override is ALWAYS stored, even when equal to the value it shadows; only value_epoch and listener dispatch key on effective change. The "equal-value set is a no-op" reading silently voids a buffer-local pin: nothing is stored, and a later global set flips the very buffer the user pinned.
    • Two scopes: global and buffer-local. get(name, buf) resolves local → global → default; get(name) resolves the GLOBAL CHAIN ONLY and never consults an ambient buffer. Per-language and per-project are patterns (a hook calling set_local), not scopes the registry knows about. Mode keymaps now resolve through #129, but pmacs.config deliberately remains global + buffer-local.
    • Buffer-locals live in a registry side table purged at after_buffer_removed, beside the keymap purge.
    • Listeners: commit → snapshot → drop the borrow → re-enter Lua; a raising listener is logged without blocking the rest or rolling back; a depth bound turns a cycle into a pointed error. Explicit dispose only — there is no MetaMethod::Gc anywhere in the codebase, and GC timing differs between the two Lua backends.
    • StartupOnly freezes off the existing InitCompleteFlag at write time (which is why no editor.rs call was needed). In --lib builds set_init_complete never runs, so a post-freeze test must flip the flag explicitly or it passes vacuously.
    • Adopters own their own define, so SourceLocation names the owning module: editing.auto-pair (pair.lua, read against the typed edit's SOURCE buffer), editing.trim-on-save (editops.lua, read against the buffer being saved), autosave.interval-ms (autosave.lua, re-read per tick). The migration wrappers keep their legacy coercion — the registry is strict, the legacy setters stay lenient (trim_on_save("yes"), interval_ms(1500.7)).
    • M-x describe-setting renders into *help*.
  • Mode system wiring LANDED — #129 (docs/mode-system-wiring-framing.md; merge b4b925d; one review round). The existing mode-keymap substrate is now live without a protocol change.
    • Buffer.major_mode: Option<String> owns the single major mode. The detected language name initializes it once on buffer.after-load, before grammar gating, so server-only languages work; switches never rewrite it. Explicit overrides and clears survive switches. A future reload that fires after-load re-detects, and explicit mode state is not session-persisted.
    • Dispatch borrows the zero-or-one mode through Option<&str>::as_slice() and &[&str]: no hot-path mode allocation. Resolution remains buffer-local → mode → global, and registry/keymap borrows end before Lua command invocation.
    • Lua surfaces: pmacs.buffer.major_mode / set_major_mode and pmacs.editor.active_modes. pmacs.describe.key, pmacs.help.show_key, and followed percent-encoded @mode: links use the same effective context; pmacs.keymap.lookup remains raw-global.
    • The built-in mode statusline provider reads ctx.buffer, so passive splits render their own mode. Real-daemon acceptance covers all ten framing criteria across both Lua backends and Linux/macOS CI.
  • Modeline language detection LANDED — #132 (docs/modeline-detection-framing.md rev 2; merge 1dd47fc). Fresh loads scan bounded Emacs -*- mode: ... -*- and Vim/Vi ft= / filetype= modelines without evaluating file content, normalize common editor aliases, and give explicit modelines precedence over inferred language.
    • builtin/runtime/syntax.lua owns one per-buffer fresh-load decision: modeline → bundled grammar extension → LSP filetype extension → exact filename → shebang. Syntax, initial major mode, pairing, comments, and LSP all reuse that pin; LSP retains its independent backing-path guard.
    • Editing a modeline or shebang does not switch an attached parser or make language-aware consumers diverge. Close/reopen re-evaluates changed file metadata. Explicit post-load major-mode overrides remain independent.
    • Bounded valid unknown names remain passive major modes without starting an unavailable parser or server. All thirteen framing criteria are covered on LuaJIT and Lua 5.4. No Rust or protocol surface changed; protocol stays v18.
  • Syntax-highlight / language-detection side-quest (#114–#118) LANDED — a one-shot arc built in sibling worktrees off main while the user's themes lane (theme-faces) ran concurrently in the shared checkout. All merged. What shipped:
    • Grammars (crate::syntax::BUILTIN_LANGUAGES): every LSP-configured language now has one — cuda, bash, dockerfile (via the ABI-current tree-sitter-containerfile, NOT the dead tree-sitter-dockerfile which pins tree-sitter ^0.20), make, cmake, python, go, javascript (+jsx), typescript (+tsx), toml, zig.
    • Detection chain and pin (builtin/runtime/syntax.lua): modeline → grammar extension → LSP filetype map → filename → shebang. User-extensible Lua surfaces include pmacs.parse.modeline_aliases, .shebangs, .filenames, language_from_modeline, language_from_shebang, language_from_filename, and the pinned buffer_language. builtin/runtime/lsp.lua delegates to that shared decision after enforcing its backing-path requirement. Grammar name MUST equal the pmacs.lsp.config.<name> key. A buffer keeps its pinned language across edits/switches; close/reopen performs a fresh bounded inference.
    • LSP configs added: dockerfile (docker-langserver --stdio), cmake (cmake-language-server, config via init_options.buildDirectory="build" — it does NOT pull workspace/configuration). Make has no server.
    • Substrate: LanguageEntry.highlights_query and .locals_query are &[&'static str] fragments joined base-first (cuda over c/cpp; ts over js/jsx). On locals-query-processing @ 47ffe5d, settle compiles the grammar's LOCALS_QUERY, resolves Tree-sitter's scope/definition/value/ reference conventions into sorted LocalFacts, and stores them beside each layer's tree/query. Work runs once per fresh bundle and only when the highlight query asks about local; viewport rendering remains bounded. Both TUI and semantic/GPU producers evaluate #is?/#is-not? local through the shared capture walk. Non-shadowed JS/TS builtins are restored; shadowed definitions/references keep ordinary variable styling.
  • Multi-language injections (#122) LANDED — the direct continuation of the #114–#118 highlight arc; four review rounds, framing docs/multi-language-injections-framing.md (Q#IJ1–IJ11). A buffer can now hold more than one language: ParseTreeBundle holds Vec<Layer> (root + injected children, depth-ascending, installed atomically so the existing StyleGate + highlight-cache Arc gates still work). The parse worker builds child trees off the static BUILTIN_LANGUAGES table (lazy load preserved) via set_included_ranges — child node offsets are ABSOLUTE, so injected spans are buffer-coordinate-native; settle resolves each layer's highlight query (SyntaxRegistry::resolve_layer_queries). First consumers: markdown fenced code + markdown_inline (retires the M9.7 block-only floor). New substrate: LanguageEntry.injections_query; default_injection_aliases + SyntaxRegistry::injection_alias_snapshot (case-folded fence names, Lua-extensible via pmacs.parse.injection_aliases, snapshotted into ParseRequest so the worker never touches the Rc registry or Lua); ParseTreeBundle.injection_capped (the 4096-layer backstop, surfaced once/buffer via pmacs.error at settle); compute_highlight_spans_for(query, tree, source, local_facts, range) (per-layer); the wire flatten_layer_spans event-sweep → DISJOINT effective spans (deeper / later-sibling / narrower wins, keyed by (layer_index, capture_order)); GPU spans_from_segments + source_color_at fold. Two findings to keep: injection ranges exclude only NAMED children (anonymous tokens ARE the injected text — excluding them shreds a block inline node; matches tree-sitter-md's own splitter), and the wire flattener runs over the WHOLE buffer via the file-style summary, so it must be an event sweep, not O(spans²).
  • JSON + YAML grammars and language servers (#123) LANDED — bundled ABI-current tree-sitter-json / tree-sitter-yaml cover .json, .yaml, and .yml; the existing injection engine now highlights YAML frontmatter and JSON/YAML fences. Default external LSP configs are the pinned vscode-json-language-server provider and yaml-language-server; configured settings are pushed after initialized, which also supports push-model servers. The fake-server delivery proof and PATH-gated live JSON/YAML provider smokes cover the configuration contract. .jsonc / .json5 remain a deliberate follow-up because the JSON grammar is strict.
  • Compile-mode (Arc 5 stage 1, #113) LANDED (2026-07-14, 7 rounds; framing docs/compile-mode-framing.md rev 13). compile.run streams /bin/sh -c "exec 2>&1; <cmd>" into an intercept-read-only *compilation* buffer via a Lua ANSI parser; once-per-newline error rules; unified error.next/error.previous (M-g n/p, C-x `, M-!). Substrate other code can use: ProcessSpec.stdin/group (group lifecycle: reap ledger, in-drain enforcement, cancellable poll readers), buf:revision(), jump_back fires buffer.after-switch, pmacs.errors.claim, AnsiParser::finish() (observable reset), and the style-overlay stack: buffer-attached BufferStyleSpanTranslator (once-per-edit, fragment-preserving), render-only window overlays with identity-deduped Window::ensure_overlay + clone_for_split, idempotent atomic handle:dispose().
  • Editing-conveniences pack (editops, #111) landed (framing docs/editing-conveniences-framing.md rev 6). goto-line, case ops, transpose, zap-to-char, line move/duplicate/join, region sort/reverse/dedupe, delete-trailing-whitespace + opt-in pmacs.editops.trim_on_save. Substrate: pmacs.killring.kill_range / break_chain([fid]) / arm_kill_prompt+commit_kill_prompt (marker lifecycle), and the origin-guard pattern for chain-sensitive minibuffer commands.
  • Auto-pairing (#110) landed — Arc 2 COMPLETE (framing docs/auto-pairing-framing.md rev 6). BUILTIN_PAIR_CHARS in pmacs-protocol leave both frontends' optimistic classifiers; builtin/runtime/pair.lua loads BEFORE lsp.lua (first-didChange ordering contract); one-shot typed-edit provenance via pmacs.editor.take_typed_edit() (buffer-revision postcondition, Q#AP9). Substrate: buf:path(), pmacs.lsp.buffer_language(buf), PMACS_FAKE_LSP_CHANGE_SINK, TestDaemon::spawn_with_config.
  • Themes (Arc 4) stages 1–3 LANDED; Arc 4 COMPLETE ON main.
    • Stage 1 (#120, docs/theme-faces-framing.md rev 9): named UI faces as reserved ui/ui.* theme entries; transactional split syntax/face epochs; protocol-v16 ThemeFacts; snapshot/baseline symmetry; store-sourced diagnostic-count freeze.
    • Stage 2 (#124, docs/gpu-set-font-framing.md rev 5): pmacs.gpu.set_font and authoritative protocol-v17 FontFacts; frontend-local family resolution, live font reload/reflow, and visual-run caret geometry.
    • Stage 3 (#125, statusline-segments, docs/statusline-segments-framing.md rev 3): composable strict pmacs.statusline providers; borrow-released per-window evaluation with failure latches; legacy-preserving TUI composition; a pure built-in LSP provider; dynamic modeline faces; protocol-v18 StatuslineSegments; authoritative-empty/snapshot symmetry; and atomic GPU validation, face resolution, shaping, clipping, and cache invalidation. Acceptance 1-27 is implemented. Final gates: Clippy clean; 1,619 default + 1,793 CRDT library tests; 7 default + 8 CRDT feature acceptance; 114 M4; 109 required GPU; one-invocation workspace sweep 2,718 passed across 78 suites (19 ignored, basedpyright filtered); git diff --check clean. Stage 3 landed as #125 and completed Arc 4 on main.
  • Vterm Stage 1 terminal core LANDED ON main — #126 (docs/vterm-framing.md rev 5; merge 643d1e1).
    • Implementation commits: bbc1f33 (Stage 1), 962944b (Darwin signal normalization), first-review fixes f0a235f, 28f2e6c, bf972a7, and second-review hardening 9797ada; reviewed feature head fc4e0ce merged through PR #126, https://github.com/levineuwirth/pmacs/pull/126.
    • AnsiParserProfile::{LineOriented, FullScreen} preserves compile/REPL behavior while terminal PTYs emit the full cursor/mode/device operation set. src/terminal/{screen,input,session}.rs owns the state machine, encoders, and lifecycle registry.
    • Public session seam: owned strict TerminalSpec; owned TerminalSnapshot; TerminalProcessState; and SharedTerminalManager = Rc<RefCell<TerminalManager>> with open/is_terminal/process_id/snapshot/tick/send/resize/terminate/prune/ shutdown. Stage 1 snapshots are context-free; Stage 2 adds per-view state without a second screen.
    • EditorState tick order is supervisor → terminal-owned PID drain/prune → process.after-tick. Terminal IDs are not exposed through pmacs.process; ordinary Lua/LSP/MCP ownership is unchanged. Terminal identity buffers are pathless, clean, empty, round-trip, and guarded read-only at every rope/CRDT/history mutation boundary.
    • Acceptance 1–14 is mapped in the framing. The real PTY bite splits ESC/CSI writes, observes alternate-screen cursor addressing, blocks and resumes through raw send, restores the main screen, and pins final output before exact PID/outcome annotation. One-row annotation visibility, TERM-ignoring shutdown, spawn rollback, buffer-kill prune, and immutable empty CRDT bootstrap are pinned.
    • Review round 1 added typed IND/NEL/RI with margin-correct screen behavior, defaults absent TERM to xterm-256color, makes shutdown liveness acceptance portable with kill(pid, 0), and preserves custom tab stops on resize. Review round 2 rejects C0/C1 controls before they enter screen cells, preserves the released button code in SGR mouse reports, removes dead screen paths, and clears stale round-trip state during prune. Stage 2 now uniquifies default terminal buffer names transactionally.
    • Exact CUU/CUD and out-of-range DECSTBM clamping, combining across controls, xterm alternate-screen details, legacy non-SGR mouse, printable ASCII and CSI-dispatch allocation fast paths, and scrollback-cap naming are explicit post-arc deferrals in the framing.
    • Final from-start rerun after review round 2: Clippy clean; 1,661 default + 1,837 CRDT library tests (3 ignored each); 9 default + 10 CRDT vterm acceptance; M4 114 passed (3 ignored, 1 filtered); required GPU 109; workspace 2,769 passed across 79 suites (19 ignored, 1 filtered); diff check clean. scripts/bite HEAD^ src/terminal/screen.rs --test vterm_stage1_acceptance terminal_cells_reject_child_control_characters is a clean behavioral bite. The parser dispatch has its independent clean behavioral bite; the original main/crate-root bite remains explicitly weaker compile-time API evidence.
    • Stage 3 owns pmacs-gpu/src/attach.rs, authenticated source routing, protocol-owned wire types/limits, and a deliberate complete-frame limit decision: 16 MiB is insufficient; use a measured legal-worst cap or aggregate bound, never silent chunking.
    • Stage 2 TUI LANDED ON main — #130 (merge 86fc1bc; docs/vterm-framing.md Revision 7, criteria 15–27). TerminalViewKey keys per-frontend/window projection state over one shared process/screen; logical row anchors retain scroll/selection through reflow. One authenticated frontend controls at most one session, with atomic replacement and release on focus/switch/kill/detach.
    • The strict pmacs.terminal Lua surface owns open/state/view/send/terminate and context-implicit scroll/copy commands; the latter error unless the invoking frontend's active window is a terminal. Fixed C-c is the per-frontend terminal escape: only its next key reaches terminal-local editor bindings, while unescaped bound keys pass through to the child. C-c C-c sends one literal interrupt. Copy drains through the acting frontend's clipboard path; active BELs drain once locally and per daemon frontend, while historical/passive bells are baseline-suppressed.
    • TUI composition paints owned terminal cells/styles only inside each window's content rectangle, suppresses document overlays, and keeps sibling splits independent. Daemon key/mouse/paste/focus/resize/detach routing uses the authenticated connection source rather than client-claimed IDs. builtin/runtime/terminal.lua provides the terminal command, view commands, and pure ui.modeline.terminal process/scroll segment.
    • tests/vterm_stage2_acceptance.rs maps Lua transactionality, shared-view isolation, clipboard/modeline behavior, and a hermetic real /bin/sh TUI PTY smoke. Stage 2 changes no wire schema or GPU renderer; protocol remains v18 until Stage 3.
    • PR #130 review round 1 (8702791) aligned dispatch with the approved escape-prefix contract, closed the non-terminal Lua error path, made controller replacement atomic, retained zero-area view anchors, removed duplicate detach work, and replaced per-view deep scrollback clones with borrowed live/published row projections. Focused child-input coverage pins both unescaped bound-key passthrough and C-c C-c.
    • PR #130 review round 2 (b9a7e40) clamps anchors into the first surviving cell when eviction cuts through a wrapped logical line, prevents ambient active_frontend from minting interactive Lua authority, names malformed explicit-context fields, restores dispatcher rationale, and removes owned cell snapshots from terminal mouse routing. The framing now records the transient v18 semantic-controller boundary and bracketed-paste injection deferral.
    • Current-main integration (3f0252f) preserves per-frontend terminal dispatch while applying the landed mode-scoped keymap, and exposes the mode, terminal, and lsp statusline providers together.
    • Post-integration gate: cargo fmt --check; strict workspace Clippy; 1,753 default + 1,929 CRDT library tests (3 ignored each); mode-system acceptance 1 default + 1 CRDT; Stage 1 acceptance 9 default + 10 CRDT; Stage 2 acceptance 4 default + 4 CRDT; statusline acceptance 7 default + 8 CRDT; M4 114 passed (3 ignored, 1 filtered); required GPU 109; workspace 2,882 passed across 82 suites (19 ignored, 1 filtered); git diff --check clean.
  • PARKED: kill-ring browser + persistence. Revision 2 framing is preserved on branch kill-ring-browser, but its 0efb5cd scout is stale and must be repeated before implementation. No PR or implementation is active.
  • Roadmap: docs/roadmap-2026-07.md (ranked arcs). Position:
    • Arc 1 (LSP utility surface) COMPLETE — completion popup (#92/#93), panels/references/outline/hover (#94–#96), plus hardening follow-ups (#102, #105, #106).
    • Arc 2 (editing table stakes) COMPLETE — query-replace (#97), kill ring + M-y (#103/#105/#106), comment-toggle (#107), auto-indent (#109), auto-pairing (#110).
    • Arc 3 (persistence) COMPLETE — saveplace/recentf (#98), desktop-save (#99), autosave/crash-recovery (#100), save-clobber fix (#101).
    • Arc 4 (themes + extensibility) COMPLETE — named UI faces (#120), live GPU font preferences (#124), statusline providers (#125).
    • Arc 5 terminal stage ACTIVE — compile mode (#113), Vterm terminal core (#126), and Vterm TUI (#130) landed; protocol/GPU Stage 3 is next.
    • Config registry COMPLETE (#127) — not a numbered arc; it was the cross-cutting substrate ranked first on docs/side-quest-backlog.md's north star, and it unblocks the editing/indent/comment items that were config-blocked.
    • Mode system wiring COMPLETE (#129) — major-mode keymaps, introspection, lifecycle initialization, and statusline display shipped.
    • Locals-query processing IN REVIEW — #134 — grammar locals metadata, lexical resolution, settled per-layer facts, and shared TUI/GPU local-predicate filtering are implemented on locals-query-processing @ 47ffe5d.
    • Remaining ranked arcs: 6 folding, 7 DAP, 8 GPU splits, plus the .ipynb arc (its JSON-grammar prerequisite shipped in #123).

2. How we work (the part that must not drift)

The user is expert and reviews deeply — they falsify framings and find real bugs in round after round. The cadence that has worked for ~40 PRs:

  1. Scout ground truth in the code before proposing anything.
  2. Write a framing doc — docs/<feature>-framing.md, numbered decisions (Q#XY1…), explicit "Ground truth", "Bets", "Deferred (named)", and an acceptance-test list. Present it and wait for explicit approval ("Go for it" / "Ready to roll"). Expect 1–3 rounds of findings first; revise the doc, don't argue.
  3. Branch off main (one feature = one branch = one PR). Commit the framing as the first commit.
  4. Implement. Every reviewer finding gets a bite-verified fix — a test that fails without the fix. Watch for vacuously-passing tests.
  5. Run the full gate suite (§3). Open the PR with gh.
  6. The user replies with "Findings" lists on the PR rounds too. Same discipline. They say when to merge — never merge unprompted.
  7. After merge: update this handoff + your memory.

Commit/PR conventions: commit messages via git commit -F <file> (no inline backticks through the shell). Authorship trailers and PR attributions must be truthful: do not add a Claude co-author trailer or Claude Code attribution unless Claude actually contributed. Clippy runs as its own step, never &&-chained.

3. Gate suite (all green before any PR)

cargo fmt --check
cargo clippy --workspace --all-targets -- -D warnings   # own step
cargo test --lib                                        # ~1500
cargo test --lib --features crdt                        # ~1672
cargo test --test <the new/touched acceptance suites>
cargo test --test m4_acceptance -- --skip basedpyright
PMACS_REQUIRE_GPU=1 cargo test -p pmacs-gpu             # 58
cargo test --workspace -- --skip basedpyright           # full sweep
git diff --check

Machine-specific caveats — re-verify on a machine you haven't used before trusting them:

  • basedpyright: the DESKTOP's local binary is broken and HANGS the m4_5_basedpyright tests — hence the --skip there. The LAPTOP has a working basedpyright 1.39.9 (verified 2026-07-10: the m4_5 test passes in 0.18s), so the skip is droppable on the laptop.
  • GPU on the laptop: AMD Radeon 780M (RADV) — native Vulkan, PMACS_REQUIRE_GPU=1 works without lavapipe.
  • Flaky-under-load tests — rerun isolated before treating a sweep failure as a regression. The m8 daemon tests and the m6 process/PTY tests (m6_1_pty_mode_lifecycle_started_then_exited, m6_8_supervisor_reaps_all_children_across_cycles) are timing-based; editor::composition_overhead_under_ten_percent is a render-ratio microbenchmark that fails ~1/3 even isolated single-threaded (already cfg!(macos)-disabled). A lone failure of one of these → rerun that test alone (-- --test-threads=1) before investigating. Also: run the workspace sweep as ONE cargo test invocation piped to a full log — a double invocation + grep -c "test result: ok" can mask real failures with a misleading 0.
  • GPU tests need a Vulkan device. PMACS_REQUIRE_GPU=1 makes absence a hard failure instead of a silent skip. Headless option: lavapipe (see docs/repository-audit-2026-07-03.md for the CI harness how-to). On a laptop without discrete GPU, mesa/lavapipe works.
  • The desktop's shell is fish (no $(...), use (...); no $UID, use (id -u)). Check $SHELL here before assuming.

4. Substrate invariants (do not undo; tests enforce most of these)

Command boundaries (Arc 2 kill-ring substrate) — EditorCore.command_history: HashMap<FrontendId, CommandBoundary{this, last}>, per frontend. Rotate on: keybound command, self-insert, menu invoke, invoke_interactive (the M-x path). Break on: unbound key, GPU optimistic CRDT edits, pointer gestures (wheel scroll deliberately does NOT break), unified paste. Plain pmacs.command.invoke stamps nothing (programmatic API); invoke_interactive rotates-then-invokes (Emacs M-x semantics). Single-codepoint optimistic CRDT inserts classify as buffer.self-insert (exact decode; "a(" breaks instead). Lua: ed.this_command() / ed.last_command().

Effective-edit returns — buf:insert/delete/replace return the post-intercept (start, end, inserted_len). Callers that care (killring, comment) compare EXACTLY against the request; length-delta and text-at-position checks are documented defeated patterns. Always pcall the mutator: a rejecting intercept must report, not throw through, and failed ops must leave no state (kill chains, yank sessions).

Kill ring — entries {id, text} with stable monotonic ids; chains and yank sessions are per-frontend and id-checked (an index is not stable under other frontends' pushes). OS clipboard mirrors to the acting frontend only. Paste is a unified daemon arm keyed by the dispatcher's AUTHENTICATED source — never a payload frontend_id.

LSP outbound positions — every Position/Range builder in src/lsp.rs routes through outbound_position (byte → negotiated encoding). Any new request builder must too; UTF-16 servers reject raw byte columns on non-ASCII text. Semantic tokens: full, full.delta, and range are three INDEPENDENT capabilities — gate each.

Persistence (Arc 3) — state-dir wiring lives in install_state_dirs() on real entry points only, NOT EditorState::new() (tests stay hermetic); PMACS_STATE_HOME overrides. Autosave: one buffer owns a path's recovery slot; only recover/discard release unclaimed crash data; adopt clears the old owner's skip cache.

Protocol — encoding-breaking bumps are deliberate and versioned (SUPPORTED=[6..18]). v15 = CompletionPopup + StatusFacts.message; v16 = ThemeFacts; v17 = FontFacts; v18 = StatuslineSegments. New wire surface ⇒ bump + both-frontends support + acceptance.

Fake LSP (src/bin/pmacs_fake_lsp.rs) modes: fullonly, rangeonly, rangeonly16 (UTF-16 + fail-closed bounds validation), sighelp. Use these for capability-matrix tests, not real servers.

5. Hard-won ops lessons

  • The checkout may be shared with the user. Check git status for foreign uncommitted work before any stash/checkout/branch surgery; never assume dirty files are yours. (Their uncommitted fix was nearly orphaned once.) A clean status goes stale within minutes when two lanes are active — for parallel work, git worktree add a sibling directory off main instead of switching the shared checkout.
  • Never git stash in this repo. The stash namespace is REPO-GLOBAL — one list shared across every worktree and with the user; a scripted push/pop can pop a human's years-old stash into your tree (happened during #111: a failed stash push chained into stash pop, which grabbed the user's PR-#17-era entry). For run-tests-against-an-old-version swaps, use scripts/bite — a trap-guarded one-file swap over read-only git show, with an inverted verdict (exit 0 iff the tests FAIL against the old version), making bite-verification machine-checkable.
  • Stacked PRs: retarget the child to main BEFORE merging the parent — GitHub auto-closes a PR whose base branch is deleted and cannot reopen it (#104 → re-opened as #105).
  • Scripted edits (sed/python) in files with repeated similar blocks (src/lsp.rs JSON builders): anchor on a unique line or you will silently edit the wrong block. This produced a vacuously-passing test and cost an hour.
  • Acceptance fixtures that open .rs/.py files must empty pmacs.lsp.config first — the after-load hook spawns real servers (rust/python/c have default configs). Language detection (grammars + pmacs.lsp.filetypes) is unaffected.
  • Test scratch buffers have no path ⇒ no language; use tempdir files when language matters.
  • Dual-purpose session state is a reset-contract trap (#120 rounds 2–5): last_status doubled as the peer emission baseline AND the stale-diag count freeze, so resetting baselines on BufferSnapshot zeroed mid-edit counts. Knowledge about a buffer belongs in shared stores (DiagnosticStore severity totals), never in per-session baselines; and any daemon-side reset needs its frontend mirror audited in the same round (the GPU snapshot arm missed search/menu/status the first time).
  • Tab width is a rendering-parity bug, NOT a config gap (scouted at 7bc0c61 while framing #127; still true). There are FIVE tab-width sites across TWO crates with TWO different values: TAB_WIDTH = 8 in src/text_view.rs, src/highlight.rs, src/diag.rs and src/completion.rs, versus advance_minimap_col in pmacs-gpu/src/main.rs expanding to 4 — and the GPU's main text path expands tabs not at all (buffer bytes reach the frontend raw, so a literal \t is shaped by the font). editor.tab-width is therefore the obvious-looking first config adopter and is not one: defining the setting cannot make the GPU honor it. Doing it properly needs frontend tab expansion plus a wire-or-frontend-local decision. Deferred from #127 on exactly these grounds; don't re-plan it as a config task.
  • A test that never runs passes. Two #127 review-round tests passed vacuously at first: pmacs.editor.save() is the RAW save, while buffer.before-save fires inside the buffer.save COMMAND (builtin/commands/default.lua), and save() no-ops on an unmodified buffer — so a fixture that opens a file and saves it asserts on bytes nothing rewrote. Dirty the buffer with a real edit and go through pmacs.command.invoke("buffer.save"). Caught only because the other case failed and the cause was chased instead of the assertion adjusted.
  • Real-grid acceptance must budget for macOS startup and path width. A 100 ms first-Hello timeout failed under loaded macOS CI; use the normal five-second handshake window, then short polling reads. An 80-column split also clipped a custom statusline segment after macOS's long /var/folders/... temp path while passing on Linux; size the grid for the longest supported fixture path (the mode-system test uses 160 columns per split).

6. Named deferrals (the standing backlog, consolidated)

Editing: word kills (M-d/M-BS — need bytes-returning deleters + prepend-on-backward append), C-SPC set-mark, C-u C-y / C-M-w, kill-ring browser + persistence, clipboard watching, block comments + mid-line comment spans, comment-dwim append-at-EOL, per-language comment padding. Pairing (framing "Deferred"): wrap-region on opener, pair-aware backspace, RET-inside-pair closer-on-own-line, in-string/in-comment inhibit (needs node-at-byte pmacs.parse), undo amalgamation (pair = one step), balance-aware quotes (the per-buffer toggle SHIPPED in #127 as editing.auto-pair). Editops deferrals (full list in its framing): recenter (blocked on viewport facts — the GPU never consumes daemon view_top), Unicode case/word classes, region-spanning move/duplicate, locale collation for sort-lines, ensure-final-newline on save. Substrate: buffer-aware edit epoch (after-edit currently compares the ACTIVE buffer only), wire provenance for CRDT self-insert classification, Lua intercept probe, completion.lua still on the old cursor-delta heuristic (migrate to this_command), the TUI's nonempty-selection optimistic type-over gate, generated-buffer search invalidation, cross-peer chronological undo arbitration (mixed source/daemon history; pinned by auto-pairing acceptance), origin-pinned buffer.after-edit fan-out (a context-switching intercept changes what later callbacks — LSP, completion — observe). LSP/persistence: hidden-buffer LSP attach, daemon desktop-restore, the warning half of external-change detection (verify-visited-file- modtime). Config registry (SHIPPED #127; these are its own named deferrals): persistence of settings and the custom-file split-brain question, M-x list-settings as a listview panel, a settings completion source for the minibuffer (minibuffer.read's source is a fixed Rust-side vocabulary), table-valued settings (so pmacs.lsp.config, pmacs.pair.sets, pmacs.comment.strings and the pmacs.parse.* write-through proxies stay raw Lua), migrating the remaining scalar setters (async_config ×2, killring.max, the enable booleans) and pmacs.gpu.set_font, pending-set staging for names defined after init.lua runs, and a scope = "global" define flag — set_local is currently accepted for autosave.interval-ms, where a per-buffer value is meaningless. Tab width is NOT a config gap — see §5. Mode system (SHIPPED #129): minor modes, buffer.after-mode-change, mode-scoped settings, describe-mode, and persistence of explicit major-mode overrides/clears across sessions. Modeline detection shipped in #132. Highlight/detection (from the #114–#118 side-quest + injections #122): locals-query processing (run each grammar's LOCALS_QUERY so #is?/#is-not? local is honored instead of the current fail-closed drop — restores .builtin styling for non-shadowed console/require etc.); injection follow-ups now the engine landed (#122) — injection.combined (many matches → one shared parse; PHP-in-HTML, some comment schemes), child-tree incrementality + range-scoped layer rebuild (child layers cold-reparse on every settle today), injectable runtime/Lua-registered languages (v1 resolves only against BUILTIN_LANGUAGES), and the next injection consumers gated on new grammars — HTML/CSS/GraphQL/SQL (<script>/<style>, JS/TS template modeline detection as a 5th layer (-*- mode: … -*- / # vim: ft=…) SHIPPED #132; byte-accurate multibyte cursor placement in move_active_cursor_to (still steps one codepoint per LSP byte column). A full Jupyter .ipynb setup (reader → editable → kernel execution) now has its JSON grammar prerequisite, but remains a real arc, not a one-shot. GPU: auto-reconnect after daemon restart, splits/multi-buffer, gutter riders (whitespace guides, folding, git markers). Themes (full list in theme-faces framing rev 9 "Deferred (named)"): popup/menu/dropdown bg + selected-row faces, ui.background / ui.caret, ui.modeline.inactive, minimap chrome, peer-cursor palette (+ui.selection for peer rects), ui.inlay_hint (needs the epoch treatment on its producer), wire alpha, Indexed palette unification, named-theme registry / light theme / persistence (the registry exists now, #127; theme persistence still waits on settings persistence), grid-vs-wire default_style asymmetry, mask widening (gutter bg, wash glyph recolor, statusline bg echo surface, chrome bold/italic/underline re-shaping). Housekeeping: F-016 lua_bindings/mod.rs split paused mid-way (tranches 0–2 landed, ~5–8 PRs left; see docs/lua-bindings-split-framing.md). Full cross-cutting index of the non-themes backlog (this list + every framing doc's Deferred section + a code sweep, themes excluded, with a prioritization north star): docs/side-quest-backlog.md.

7. Machine-local facts (desktop) that do NOT travel

Three untracked files live only on the desktop working tree and are deliberately never committed: docs/pmacs-gpu-editing-perf-handoff.md, docs/session-5-stale-styling-handover.md, python_experiment.md. Don't expect them in a clone; on the desktop, never delete them.

8. Update protocol for this file

When a PR merges, an arc opens/closes, or a decision lands: edit the snapshot (§1), append lessons (§5) and deferrals (§6) as they arise, bump the date line at the top, and commit — usually riding the same PR as the work. Keep durable architecture here; put branch hashes, machine-local tools, incomplete verification, and recovery commands in docs/active-work.md. This is a briefing, not a log: prune sections that stop being true.