The two halves of the system run on opposite statistical philosophies, on
purpose, and until now the docs never said so. The optimizer is a Bayesian
detective: playbook prior, ledger evidence, policy ranking, explain
feedback — belief-updating that decides what to try next. The trust layer
is a frequentist court: equivalence gates, per-machine calibrated error
rates (A/A false-positive bound, injected-regression power bound), and a
CI-lower-bound accept rule with no prior anywhere on the accept path —
because its audience is a hostile reviewer who shares none of your priors.
The load-bearing edge is the return path: evidence flows from court to
detective (ledger rows + explain); authority never flows the other way.
Invariant, now stated in four places: priors steer where we look; they
never touch what we conclude. A wrong prior costs compute — each wasted
attempt honestly ledgered. A prior in the verdict would cost a false
claim, the one unrecoverable failure for a project whose product is trust.
- thesis.md: full section with the two-box diagram incl. the return edge,
in docket order (equivalence before measurement); notes that estimated
payoff is a belief and dollar figures are minted only by the mechanical
report from accepted rows, and that even the learning layer bets on
Wilson LOWER bounds — the detective is a pessimist too.
- README: the one-breath version, linking the full argument.
- SPEC §1: dated note mapping each half to its sections.
- CLAUDE.md: the mental model, one paragraph under Mission.
Framing credit: emerged from a design conversation on whether peltier is
"Bayesian engineering" — it is exactly half of one.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Verdicts say what; nothing said why. A rejection that reads only
rejected-bench teaches nothing, and the loop's compounding value is that
the next hypothesis is better than the last. This ships the teaching layer,
built so it can never contaminate the thing it explains.
New crate crates/explain (`just explain <run-id>`):
- Advisory, strictly off the accept path: runs after the verdict is
recorded; nothing it emits feeds gates, bench, verdict, or ledger. Not
agent-facing: harnessd stays at seven ops, by design (SPEC §3.7 says why
- better hypotheses must never become a feedback channel into
measurement).
- Ledger-only inputs, deterministic: consumes exactly one row via the new
ledger::attempt_row; no config, no clock, no re-benching. Identical row,
byte-identical text - proven live (cmp on two runs of a real row).
- Record vs inference is typographic: restatements print plain; anything
beyond is prefixed `inference:` so an explanation can never be quoted as
a measurement.
- The narrative must agree with the machine verdict. The first live run
caught this class of bug: an accepted row without a recorded threshold
was narrated as "a policy rejection" two lines under "verdict: accepted".
Accepted rows are now always described by their CI lower bound (the
defensible claim); rejected-bench rows classify against 1.0 (measured
regression / null result / real-but-below-bar); NHR rows name the
recorded cap and state the numbers were not the deciding factor;
rejected-gate rows name the failing gate. Regression-tested.
- Historical rows are flagged, not laundered: accepted with
sanitizers_clean=false prints the doctrine caution (comrak-010 shows it);
fuzz_iters=0 accepts are named pre-integration rows.
verdict now records accept_threshold (the bar in force for that run) into
the bench env fingerprint, so rows are self-contained going forward -
explain never substitutes today's config for a historical bar, and says so
on older rows instead.
SPEC §3.7 (Added 2026-07-20) carries the invariants; book chapter
docs/src/explain.md shows real output from real rows (the accepted cJSON
win, the caught false-accept, the kernel-lane NHR); CLAUDE.md, README,
justfile, and the architecture layout updated (the layout also gains the
previously-omitted crates/policy line).
Verified: 21 workspace test suites green (6 new explain tests incl.
determinism and verdict-narrative agreement), clippy -D warnings clean,
fmt clean, mdbook builds, live runs against phase3-cjson-002,
phase5-matmul-opt, phase2-comrak-010, and phase4-cjson-service.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
On a Windows host the preflight's job is to deliver a structured refusal
(measurement is Linux/POSIX-only). But a Windows-native harness with no
POSIX shell never got that far: preflight.sh fails to LAUNCH, and an agent
staring at "sh: not found" is exactly the agent that hand-rolls a timing
loop. The refusal doctrine has to be as portable as the skill.
- scripts/preflight.ps1: faithful port of the preflight contract, runs on
Windows PowerShell 5.1 and pwsh 7+ on any OS. Host check first (so
Windows refuses before touching anything), same walk-up resolution, same
always-build rule, same key=value output, same exit codes. The source is
pure ASCII with the shared em dashes composed at runtime — Windows
PowerShell 5.1 misdecodes BOM-less UTF-8, and that exact bug class
already bit this machine once (the francis-watchdog parse failure).
- Two implementations of one contract is a drift risk, so it is gated like
every other claim in this repo: the skill-preflight CI job now runs BOTH
scripts on the same ubuntu host and byte-diffs their stdout on all three
paths (in-checkout resolve, no-checkout refusal, PELTIER_HOME from a
foreign repo). Disagreement is a red build, not a footnote.
- New skill-preflight-windows job (windows-latest): asserts the native
refusal end-to-end under Windows PowerShell 5.1 AND pwsh (STATUS=refuse,
nonzero exit, the 'unsupported host' reason), plus Git Bash sh for good
measure. Verified live on a real Windows 11 box before shipping: 5.1
parses the pure-ASCII source clean and refuses with exit 1.
- SKILL.md / references/verify.md: document the second entry point ("use
whichever your host can launch; never both, never neither"); book chapter
and CLAUDE.md updated to match. .agents mirror regenerated (identical).
The ZeroClaw variant is unaffected: rm -rf scripts/ drops the ps1 too,
and its audit still passes (7 files scanned).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The SKILL.md Agent Skills standard (agentskills.io) is now read natively by
Codex, Copilot, VS Code, Cursor, Gemini CLI, opencode, Goose, Amp, Zed,
Factory, and ZeroClaw — so the portable move is not per-harness adapter
files (forked content that drifts) but one canonical skill placed where
each harness actually looks.
- Spec-compliant frontmatter: license, compatibility (the Linux-only
measurement story, stated up front), version/author/tags top-level
(ZeroClaw's runtime reads those; the spec ignores unknown fields).
reference/ renamed to references/ per the spec's conventional layout.
- .agents/skills/peltier/ mirror: the cross-tool convergence path (Codex,
Zed, Cursor, Gemini CLI, Copilot, opencode, Goose, Amp). Byte-identical
to the .claude canonical, enforced by CI — drift between the two copies
is a red build, not a footnote.
- AGENTS.md at the repo root for the ~20 harnesses that read it (Claude
Code does not; CLAUDE.md remains its file). Deliberately thin: it points
at CLAUDE.md and the skill instead of restating rules.
- scripts/install-skill.sh: stamps a consumer repo at both discovery paths
(--layout claude|agents|both), or emits a script-less --zeroclaw-variant.
ZeroClaw's skill security policy blocks script files by default
(skills.allow_scripts off) — its audit rejected the full skill and passes
the variant, verified against the real zeroclaw binary. The variant loses
nothing: preflight.sh still exists exactly once, in the peltier checkout
the skill already requires, and SKILL.md now documents running it from
there. Re-implementing preflight inline is named as a refusal condition.
- CI (skill-preflight): frontmatter upgraded to a full Agent Skills spec
conformance check on BOTH copies (name rules, dir match, description and
body limits, metadata string-map), plus mirror equality and a functional
installer test (both layouts identical to canonical, variant carries no
scripts/, nonexistent target refused).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The reusable artifact here was never the vendored targets — it is the
discipline: prove equivalence, prove significance, or claim nothing. This
packages it as a Claude Code skill usable from any repo.
Two modes. `verify` works anywhere, on any two shell commands in any
language: equivalence before timing -> A/A calibration -> interleaved A/B
with a bootstrap CI -> a verdict decided by the CI lower bound, never the
median. `attempt` drives the full in-repo loop (gates, pristine-baseline
verdict, ledger row, ROI report).
It drives the real bench-runner binary and refuses rather than degrade: on
an unsupported host, or with no trust layer reachable, preflight stops and
says so instead of falling back to a hand-rolled timing loop. A second copy
of the statistics is a second thing that can lie. A refusal ends the claim,
not the work.
An adversarial review of the skill caught six high-severity defects, all
fixed here — several of them the very errors the skill exists to prevent:
- verify mode had no risk classification at all. bench-runner emits only
accepted/rejected-bench; needs-human-review is minted by the in-repo
verdict path, which verify does not run. A concurrency change with
byte-identical output would have sailed through as "accepted". The skill
now makes the agent the classifier and says so explicitly.
- the accept template exposed `pin_prefix`, which is inert for
compare/aa/calibrate (only `verdict` reads it) — an agent would have set
it and reported pinning that never happened. Now documents wrapping both
sides in taskset instead.
- the equivalence gate compared stdout only, so two commands that write to
stderr and a dist/ tree would "GOLDEN PASS" on two empty files. Now hashes
stdout + stderr + exit code + artifact tree, and an empty diff over empty
output is a failed gate, not a passed one.
- nothing told the agent to build two coexisting immutable artifacts, so a
`cargo run` baseline could rebuild from the patched tree mid-bench — the
exact trap phase1-verdict-smoke-001 recorded.
- service mode was documented as generic HTTP. It is not: the server must
take <port> <doc> <iters>, print READY, and close the connection. A stock
Express app hangs the harness forever. Contract now stated.
- the CI refusal test could not pass: preflight also walks up from its own
location, so running it in-place found this very repo. The test now copies
the skill out of the tree first.
CI job `skill-preflight` asserts the contract that matters — resolve when a
trust layer is reachable, REFUSE when it is not, and work when consumed from
another repo via PELTIER_HOME. It deliberately does not assert a statistical
outcome: a shared runner is too noisy for that, which is precisely why the
skill calibrates before it claims.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
An adversarial audit found the enforcement story ahead of the code: gates
that were documented as hard gates were advisory, manual, or absent, and
several human-facing claims outran the machine record. This makes the
claims true.
High findings
- Differential fuzz was documentation, not enforcement: verdict hardcoded
fuzz_iters=0 and diff-test hardcoded the gate to Skipped, while the case
studies claimed 10k-iteration fuzz on the same wins. Fuzz is now a real
pipeline gate (strict FUZZ-RESULT contract, executed count recorded), and
it is inherently baseline-vs-candidate, so it runs on the accept path and
reports Skipped in the standalone `just gates` flow. New hard rule: a
machine `accepted` verdict is impossible unless the fuzz gate actually
passed — otherwise it caps at needs-human-review.
- The agent's system prompt claimed FP/concurrency/unsafe patches were
"routed to human review automatically". No such mechanism existed. Added
a conservative lexical risk classifier (crates/verdict/src/risk.rs) that
forces needs-human-review on any would-be accept carrying those signals;
fp-tolerance equivalence always signals.
- The local verdict path ran agent-influenced code unsandboxed. It now runs
under scripts/no-net.sh (network namespace) and fails closed. Upstream
test suites are hash-verified against corpora/<t>/TESTSUITE.sha256 when
present (scripts/pin-testsuite.sh generates them).
Also fixed, found while fixing the above
- The pipeline script's `set -e` was inert (brace group as the left operand
of `&&`), so a failing candidate build did not abort the run and verdict
could bench a stale binary. Now a scoped subshell whose status is branched
on at top level.
- A wrapper that exits before exec'ing (no-net.sh refusing, bad wrapper path)
stranded RUNNING.lock and left read_verdict polling forever. Failure
accounting now lives outside the wrapper.
- harnessd's patch allowlist ignored git rename/copy headers and --no-prefix
diffs; the rename-escape case is now a committed regression test.
- The workspace did not compile on Windows (ungated Unix APIs). cfg-gated;
71 portable tests now run on both platforms.
- pin-check regenerated the corpus manifest instead of verifying it; it is
now verify-only, with a deliberate `just pin-corpus` to re-pin.
- Max RSS is captured per run on Unix; PMU counters are opt-in diagnostics
(compare --perf-stat), never part of the accept decision.
Docs now match the code, including what is NOT yet enforced: no target ships
a TESTSUITE.sha256 pin, no target declares [build].tsan, and matmul is not
wired to the fp-tolerance gate — each is stated as mechanized-but-inert
rather than done. Corrected the stale "33 ledger rows" (34), the playbook's
class-3 cJSON win (rejected), adversarial-review.md's sanitizer-separation
claim (five accepted rows carry sanitizers_clean=false), the unsupported
"40,000 requests" figure, and the blanket "historical rows record
fuzz_iters=0" (8 of 10; phase0-tokei-002/-003 record 4,332).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Phase 5 write-up for the two SPEC §13 forks now that both are built:
- results/phase5/README.md — the full argument for each fork, with the
kernel-lane demo and learned-policy ranking tables and reproduce commands.
- results/phase5/learned-policy.txt — captured `cargo run -p policy` output
over the 34-row ledger.
- docs/src/research-forks.md — new mdBook chapter, wired into SUMMARY.md.
- docs/src/roadmap.md — Phase 5 row added; the Frontier section rewritten
from "out of scope" to "built, both routed to human review", with the
honest note that the actual GPU run needs GPU hardware absent here.
- CLAUDE.md — Phase 5 COMPLETE status paragraph.
No trust-layer or gate change; this is documentation of work already
committed (learned policy b7297ad, kernel lane 5abeb60).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
phase4-cjson-service (ledger): the accepted batch win phase3-cjson-002
measured under a 150 rps coordinated-omission-correct replay (20 rounds,
40k requests, 0 drops). p50 latency +6.2%, 95% CI [+5.8%, +7.2%] —
accepted; p99 CI [0.07, 4.97] too noisy (single-worker loopback tail),
harness correctly rejected. ROI (500-core fleet, $0.04/core-hr): 27.5
cores / $9,621/year at the CI lower bound, report generated mechanically
(results/phase4/cjson-service-roi.md).
- results/phase4/: case study + README + the generated ROI report.
- CLAUDE.md: Phase 4 complete; Phases 0-4 all done.
All SPEC §5 exit criteria met across every phase; zero shipped false
accepts across the whole project.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
20 audited attempts, 0 shipped false accepts, 3 verified auto-accepted
wins (tokei class-5: +10.7%, +3.7%, +9.9%; ~1.25x vs upstream with
Phase-0 wins). Independent 20-way adversarial re-audit (phase2-final-audit
workflow) confirmed every verdict follows its evidence, correct
equivalence tier, no harness-gaming, ledger append-only intact.
Closeout changes:
- case study: full 20-row attempt table, scoreboard, corrected
comrak-010 CI upper bound (+12.1%, was +12.2%), exit-criteria section
flipped to ALL MET, OS-isolation gap marked closed.
- CLAUDE.md Current-phase line: Phase 2 complete, next Phase 3.
- verdict: derive the ledger 'phase' column from the run_id namespace
(phaseN-*) instead of the hardcoded 1 the re-audit flagged; historical
rows are immutable and stay as written (run_id prefix is authoritative).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
The Claude Agent SDK loop (agent/hotpath_agent/loop.py, model
claude-fable-5) drives the seven harness tools over a standalone stdio
MCP server (mcp_server.py) and runs the full profile -> hypothesize ->
patch -> gated-verdict cycle on comrak with no human in the loop.
Three audited attempts, all honest rejections, ZERO false accepts:
- phase2-comrak-001 class 3: syntect buffer with_capacity, [0.971,1.007]
- phase2-comrak-002 class 5: gate dead VecDeque build, [0.982,1.026]
- phase2-comrak-003 class 6: hoist find_special_char check, [0.970,1.007]
The agent picked the cheapest untried class each time (3->5->6) and
TWICE refused to fabricate a verdict it couldn't read back, verifying
ledger integrity instead — the anti-reward-hacking behavior SPEC §10
targets.
Harness changes surfaced by the loop:
- run_verdict is now async: launches the multi-minute build+bench
detached (past the 60s MCP transport cap) and returns immediately;
new read_verdict op polls the append-only ledger row (ledger
verdict_summary). Fixes attempt 001's unreadable-verdict gap.
- read_target_source takes offset/limit line windows so 100KB+ files
page instead of overflowing — removes the agent's reason to reach for
a shell (attempt 003 paged a 2400-line file cleanly, no shell).
Honest boundary note (case study + code comments): in THIS dev
container the SDK tool allow/deny layer is defense-in-depth, not the
trust boundary — a nested CLI as root under a parent session doesn't
reliably gate built-ins. SPEC §10's boundary is OS process/user
isolation; that hardening is the remaining Phase 2 exit item
(docs/infra.md). What holds regardless: propose_patch is the only
mediated write path (path-allowlist + git apply) and the ledger is
append-only.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
Full-protocol calibration on a GitHub-hosted runner: A/A false-positive
0/20, injected-5%-slowdown detection 20/20, per-session CIs transcribed
with run provenance (artifacts expire; the md is the durable record).
With the local-container anchor and gates running end-to-end on both
targets in CI, all SPEC §5 Phase 1 exit criteria are met on free
infrastructure. CLAUDE.md phase line moved to Phase 2 (agent);
dedicated pinned hardware remains listed in docs/infra.md as the bar
for Phase 3/4 customer-facing case studies.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
The agent's only door to the trust layer (SPEC 3.5, 10): harnessd
serves read_profile, read_ledger, read_playbook, read_target_source,
propose_patch, run_verdict over stdio JSON lines. propose_patch
enforces the path allowlist (relative paths only, no parent
components, no .git, target name validated) before git apply --check
+ apply rooted in the target workspace; run_verdict builds the
candidate into an isolated dir and hands off to the verdict pipeline
(pristine-rebuilt baseline included). Python client
(agent/hotpath_agent/harness.py) + tools.py rewired from stubs to
live calls.
E2E evidence: escape attempts refused (bad target name, ../ paths,
trust-layer diff touching config/accept.toml rejected before any
apply); benign doc patch applied, candidate built, full verdict ran
mechanically end to end -> +8.9% [1.079, 1.104] accepted (ship-tree
patches ride along as the candidate), ledger row phase1-ipc-smoke-001.
Phase 1 caveat recorded in the daemon header: same-uid filesystem
read-only enforcement still needs the separate-user/container setup.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
Adds crates/verdict ('just verdict'): runs the core gates on the
candidate binary, then an interleaved A/B bench vs the baseline with
the CI-lower-bound rule, and writes the append-only ledger row with
per-side median CIs, workload statement, and env fingerprint. Gate
failure short-circuits to rejected-gate; --needs-human-review caps an
accepted verdict (never upgrades). CPU pinning moves into accept.toml
(pin_prefix, machine-specific, applied to both sides identically).
The smoke test caught a real trust gap: pointing --baseline-bin at the
workspace build (phase1-verdict-smoke-001) measured patched-vs-patched
and returned null, because gate runs rebuild the workspace binary from
the patched tree. Fix: --rebuild-baseline stashes the patch, builds
the baseline into isolated targets/<name>/baseline/, and restores the
patch — SPEC 3.1's pristine-checkout rule, now enforced by the
harness. Re-run (phase1-verdict-smoke-002) reproduces the Phase 0
result mechanically: +10.4% median, 95% CI [1.0932, 1.1137], accepted.
Both smoke rows are in the ledger, including the null one.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
Adds the diff-test CLI ('just gates <target>'): loads
targets/<name>/target.toml (new [corpus] section: manifest, root,
golden_sha256; commands now repo-root-relative), verifies the corpus
manifest FIRST and refuses to run any gate on mismatch, then runs the
upstream test suite and golden replay (stdout sha256 vs pinned hash).
Differential fuzz and sanitizers remain per-attempt manual steps in
Phase 1 and are reported as skipped-with-reason; all-skipped is not a
pass.
Verified end-to-end on both vendored targets (comrak: 1 pinned file,
848 tests, golden PASS; tokei: 545 pinned files, 250 tests, golden
PASS) and the refusal path (tampered corpus -> 'HASH MISMATCH ...
refusing to run' before any gate executes).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
Adds 'bench-runner calibrate': N A/A sessions counted against a <5%
false-positive bar, and N sessions with a synthetic slowdown injected
as a real busy-wait inside the candidate's timed window, counted
against a >=95% detection bar (detected = ratio CI entirely below 1.0).
Bootstrap seed varies per session so resampling noise is not
correlated across the very statistic being validated. JSON evidence
includes per-session CIs, injected wait, acceptance verdict, and env
fingerprint.
First run against the real comrak workload (20+20 sessions, pinned
core): false-positive rate 0.000, detection rate 0.950 -> PASS.
Evidence: results/calibration/2026-07-06-comrak-full-calibration.json.
Closes the SPEC 3.1 acceptance-criteria gap; remaining Phase 1 gaps:
no-net containers, perf profiling, diff-test orchestration, agent IPC.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
Attempt 4 (phase0-tokei-002, class 3, ACCEPTED — first auto-accept):
every file was read through encoding_rs_io's DecodeReaderBytes via
generic read_to_end, which zero-fills every grown buffer chunk (~221MB
memset/run, 8.5% of Ir) and grows without a size hint. Patch: fs::read
with a BOM-gated fallback to the identical decode path (a UTF-8-BOM
file transcodes invalid sequences, so the fallback is required for
equivalence). Gates: golden byte-identical; differential fuzz old-vs-
new binaries 4,332 iterations (BOM grid, invalid UTF-8, binary junk,
randomized) zero divergence; 250 upstream tests green; ASan+LSan clean
with ASan-run output hashing to golden. Bench: +9.9% [8.0%, 12.7%].
Attempt 5 (phase0-tokei-003, ship tree, ACCEPTED): stacks fat LTO+cgu=1
(real +1.6% standalone but under threshold, phase0-tokei-001) on the
accepted patch; benched as a whole vs pristine: +10.4% [8.5%, 12.0%].
Median clears the Phase 0 exit bar; CI lower bound 8.5%.
Case study written (results/phase0/case-study-tokei.md), ledger at 5
attempts, CLAUDE.md phase line moved to Phase 1, next hypotheses
logged (tokei class-5 byte-skip table; comrak class-3 arena).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
Session-level non-negotiables, architecture map, phase tracker,
command surface, and definition of done for one optimization attempt.
Commands section notes the currently built command-level harness
entries alongside the planned per-target ones.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
benbrownandClaude Fable 5