2026-05-14 — Session-end breadcrumb: 4a-α shipped, 4a-β is the road tomorrow

Recovery anchor for next-session me. Read this first if compaction hit overnight.

What shipped today (commit chain on arc-170-gap-j-v5-deadlock-state)

Commit	What
3c3fb10	Rescope inscription: thread/process conflation correction; 5-stone chain replacing wrong-direction 5cf134d BRIEF; INTERSTITIAL § 2026-05-14 names the substrate model; new BRIEF + EXPECTATIONS for stone 4a-α; SUPERSEDED prologues on yesterday’s BRIEF + EXPECTATIONS
ddb3cad	Slice 4a-α SHIPPED — :wat::test::run-thread Layer 1 macro + run-thread-driver + failure-from-thread-died helper minted in wat/test.wat; standalone deftest at wat-tests/run-thread.wat proves Ok-path + Err-path; SCORE 6/6 PASS; workspace 2264/9 (below 11 baseline)

Lessons earned this session (the ones that must not repeat)

1. Thread/process transport conflation. I pattern-matched stdio-capture machinery from run-hermetic-driver (pipe drain + extract-panics) onto a hypothetical thread driver. User taught the correction: stdin/stdout/stderr are PROCESS-process comm wires (OS pipes carrying EDN across fork); Sender/Receiver are THREAD-thread comm wires (crossbeam, typed in-process). Threads don’t have their own stdio because they share the parent’s fd 0/1/2. The substrate model is ONE wat surface (<I,O>), THREE transports (crossbeam / pipes+EDN / TCP+EDN); the wat-level caller doesn’t know which transport.

2. spawn-thread vs spawn-process fn-arity asymmetry. spawn-thread requires :Fn(:Receiver<I>, :Sender<O>) -> :nil per arc 114 (runtime.rs:16543-16547). spawn-process accepts [] -> nil (Layer 1 contract at test.wat:567 — only for spawn-process). The two substrate primitives diverge at this layer; the run-thread macro absorbs the divergence via unused _in/_out channel params (stream.wat:94-99 idiom). The test-writer surface stays symmetric. Future-me: when minting any thread-side helper, ALWAYS check what eval_kernel_spawn_thread expects — don’t assume symmetry with eval_kernel_spawn_process.

3. Citation discipline. I cited task #296 (“three substrate services in_progress”) as a deftest-flip blocker without reading runtime.rs:16623 — the services code is SHIPPED; the task-tracker label is stale paperwork. Lesson: every assertion about substrate STATE needs grep evidence at the moment of the assertion; tracker labels can lag the code.

4. “Going to study” must be ACTUALLY studying. I drafted a reading list and halted — the user called it out as lying. The asking IS the signal; just read. feedback_asking_to_read_means_read violation; tightened.

What’s on disk tomorrow-me needs

• BRIEF-SLICE-4A-ALPHA-MINT-RUN-THREAD.md + EXPECTATIONS-SLICE-4A-ALPHA-MINT-RUN-THREAD.md + SCORE-SLICE-4A-ALPHA-MINT-RUN-THREAD.md — slice 4a-α complete record.
• BRIEF-SLICE-4A-LEGACY-TEST-RUN-SWEEP.md + EXPECTATIONS-SLICE-4A-LEGACY-TEST-RUN-SWEEP.md — both SUPERSEDED (prologues land at file top); preserved as failure-engineering artifacts.
• INTERSTITIAL-REALIZATIONS.md § 2026-05-14 — the rescope rationale + the substrate model + the conflation record + (after this entry) the session-end breadcrumb.

Recovery instructions for next-session me

1. Read this entry first. Then read INTERSTITIAL-REALIZATIONS.md § 2026-05-14 (the rescope rationale + substrate model) — that’s the architectural context tomorrow’s work rides on.
2. Verify state on disk:
   • git -C /home/watmin/work/holon/wat-rs log --oneline | head -10 should show ddb3cad (slice 4a-α) at the tip.
   • git status --short should be clean.
3. The chain (in the task system, not in git):
   • #308 (4a-α mint) → COMPLETED today
   • #313 (4a-β sweep 32 callers) → NEXT — pending, unblocked
   • #314 (4a-γ flip deftest macro body to run-thread) → blocked by #313
   • #315 (4c-α delete legacy wat wrappers) → blocked by #314
   • #316 (4c-β rename run-thread → run + run-thread-driver → run-driver) → blocked by #315
   • #310 (substrate Rust deletion) → blocked by #315 + #309
   • #312 (INSCRIPTION) → blocked by #316 + #310 + #311
4. The first thing to do tomorrow: draft BRIEF-SLICE-4A-BETA-SWEEP-LEGACY-CALLERS.md + EXPECTATIONS-SLICE-4A-BETA-SWEEP-LEGACY-CALLERS.md. Sweep 32 callers per the original BRIEF’s pattern catalog (P1: :wat::test::run string-form, 5 sites; P2a: :wat::test::run-ast literal-vector, 18 sites; P3: :wat::test::run-hermetic-ast, 9 sites). DESTINATIONS CORRECTED PER TODAY’S RESCOPE: 23 thread-based callers → :wat::test::run-thread; 9 hermetic callers → :wat::test::run-hermetic. The old BRIEF’s P-pattern decomposition + STOP triggers are reusable; the destination split is what changes.
5. DO NOT redo 4a-α. The mint shipped at ddb3cad; the run-thread primitive is functional and verified; #313’s sweep operates on the settled foundation.
6. DO NOT touch deftest macro yet. 4a-γ does the flip; 4a-β is sweep-only.
7. Substrate divergence pattern is already in use. When writing 4a-β BRIEF, note that callers migrate to (run-thread <body>) / (run-hermetic <body>) — body-only macros; the unused-channel idiom is INSIDE the macro, not at the call site. Test writers see no transport difference.

Open follow-up tracked (not deferred, surfaced for whoever does the Rust-side cleanup)

• runtime.rs:17485 stale doc comment. References wat/kernel/sandbox.wat’s failure-from-thread-died which no longer exists. The new :wat::test::failure-from-thread-died (test.wat:622) is the only wat-side caller of ThreadDiedError/to-failure in the loaded stdlib path. Doc comment cleanup is appropriate during the Rust-side substrate work in #310 / #311 — surfaced here so it isn’t lost.

The voice for tomorrow

This session’s discipline catches:

• Read disk before asserting substrate state
• “Going to study” means READ NOW, not “compile a reading list”
• Substrate asymmetries are honest (spawn-thread ≠ spawn-process arities); discover before drafting
• Stepping stones over one-shot — 4a-α as the foundation 4a-β rests on; the split was right
• Atomic commit per slice; SCORE before commit; orchestrator verifies independently

The boss (arc 170 closure) is closer than yesterday. Stone 4a-α was the architectural correction’s first proof-of-concept; 4a-β is mechanical sweep on settled foundation. The substrate teaches; we listen; we ship.

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