- Profiles regenerated with callgrind --cache-sim --branch-sim for both
targets: per-function D1/LL miss and branch-mispredict columns unlock
playbook class-4 preconditions (comrak: syntect write_highlighted owns
31% of D1 read misses; tokei: parse_lines owns 56% of Ir).
- tokei workspace: accepted Phase 0 wins banked as a local commit so
stash-based baseline rebuilds attribute only the marginal patch to new
attempts (false-accept trap closed before grinding).
- read_ledger now returns per-attempt history (class, hotspot,
hypothesis, verdict): a class may be re-entered with a materially new
hypothesis, never a duplicate one. Task prompt updated to match.
- read_verdict long-polls the ledger up to 45s server-side (under the
60s MCP cap), cutting the agent's polling turn burn ~15x.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
harnessd gains --socket mode (Unix socket, trusted uid, mutating ops
serialized); the harness client speaks socket when
HOTPATH_HARNESS_SOCKET is set. scripts/agent-isolated.sh launches an
attempt with the agent tree confined — mountns mode (repo bind-mounted
read-only, CAP_SYS_ADMIN/CAP_SYS_PTRACE dropped; no credential copying)
or user mode (unprivileged hpagent, bench-metal shape).
scripts/isolation-check.sh + just isolation-check verify the boundary
from the agent's side: 19 checks, both modes, all passing — repo
writes, forged ledger INSERTs, trust-binary replacement, rw remounts,
and userns re-entry all refused; the harnessd socket door works.
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
Closes the CI-reachable slice of the Phase 1 infra gaps:
- trust-layer job: cargo test + clippy -D warnings + fmt
- target-gates-no-net: fetches pinned targets (new targets/fetch.sh),
regenerates + verifies corpora, runs 'just gates tokei'
mechanically, and executes the bench workload inside a
--network=none container (SPEC 3.1/10 no-net requirement)
- runner-calibration (informational): A/A + injection harness measures
the shared runner's noise floor per run, evidence uploaded as an
artifact — environments are judged empirically, not assumed
- perf-probe (informational): reports which perf event sources work
docs/infra.md maps each remaining hardware requirement (pinned cores,
governor/SMT control, separate-uid trust layer) to the bench-metal
self-hosted runner setup a human can complete in ~15 min.
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
Commit the spec and scaffold the system it describes:
- SPEC.md: the full v0.1 engineering spec
- crates/: trust-layer Rust workspace, unit-tested
- bench-runner: interleaved ABAB scheduling with discarded warm-ups,
deterministic bootstrap CIs over the ratio of medians,
CI-lower-bound accept rule, env fingerprinting, and a CLI with
compare + A/A self-test modes (A/A verified passing end-to-end)
- diff-test: gate outcome model, sha256 corpus pin verifier that
refuses on mismatch, per-target equivalence policy parser
(byte-identical default, explicit fp-tolerance opt-in)
- ledger: append-only SQLite attempt schema with UPDATE/DELETE
refused by triggers, anti-double-attempt query
- report: cores-saved and dollars/yr ROI math over speedup CIs,
pricing.toml inputs
- playbook/: classes 1-7 with preconditions, procedure, verification
notes, and known failure modes per class
- agent/: Python package skeleton — six-tool contract and prompting
spine, harness IPC deferred to Phase 1
- config/: accept.toml (2% threshold, 30 runs/side), pricing.toml
- targets/, corpora/, results/calibration/: layout and policy docs
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
Claude