CCF 2026: The Runtime Trust Certificate Floor — Telling a Real Signal From Rounding Noise in Autonomous-Agent Trust Verification
A runtime trust certificate floor for autonomous agents: a per-step, dynamic finite-precision threshold that separates a real loss-of-contraction signal from machine rounding noise. Real Rust benchmarks across f64/f32/fixed-point.
Every runtime trust certificate for an autonomous agent eventually runs into
arithmetic. As a trust value homes in on its target, the per-step change shrinks —
until it's smaller than the rounding error of the computer making the change. At
that point the residual you measure is noise, not signal. Hard-code a single
tolerance like κ_t < 1e-9 and you get the worst of both worlds: a 32-bit
controller never believes it converged (its rounding floor is bigger than 1e-9),
while a 64-bit one declares victory with a thousandfold of real movement still
left. This is the runtime trust certificate floor problem, and it sits at the
center of CCF's Prov 6 architecture for verifiable autonomous-agent trust transfer.
CCF's Prov 6 (US 64/092,485, filed 2026-06-17) accepts a realized trust step only
when its per-step quotient-affine-contraction (QAC) residual κ̂_t clears a
dynamic finite-precision floor, recomputed every tick:
floor_t = 2·n·ε_q + |Δα_t|·E_t
2·n·ε_q— the rounding accumulated across then-term gauge/normalization step.|Δα_t|·E_t— slack for legitimate movement when the gate changes the step size.
The certificate has three states, and the third is the point: residual above
the floor and shrinking → CERTIFIED_CONTRACTING; at or below the floor →
NOT_CERTIFIED ("I can't tell" — honest, not a false pass); above the floor and
rising → EXCURSION → fail closed. This PoC implements floor_t in isolation and
measures it. Underclaim, on purpose: it does not prove trust convergence, and
Sinkhorn/gauge normalization is treated as presentation, not the causal trust
dynamic. (See Prov 6 dynamic-floor disclosure; cf. the gauge posture in [0099–0101].)
crates/research/runtime-trust-certificate-floor/ — a zero-dependency Rust crate.
One QAC iteration (affine contraction in a log-style chart + mean-subtraction
gauge) runs over four precision backends behind a Scalar trait: f64, f32,
fixed-point Q1.30, fixed-point Q1.14. The same algorithm, four noise floors.
10 tests, no mocks; floor-demo + floor-bench binaries print every number below.
| Approach | What it certifies | Runtime? | Numeric residual? |
|---|---|---|---|
| Certified roundoff bounds (arXiv 1507.03331, 1707.02115) | program roundoff error | offline | yes (static) |
| Equilibrated-flux residual cert. (arXiv 2602.01636) | verified PDE outputs | offline | yes (static) |
| Microsoft Agent Governance Toolkit | policy compliance | runtime | no |
| EQTY Lab Verifiable Runtime | attested execution (TEE) | runtime | no |
| CCF Prov 6 floor (this PoC) | trust-step is signal vs. noise | runtime, per-step | yes, dynamic |
Static roundoff certification is one-shot; 2026's agent-governance wave does policy and hardware attestation. None compute a runtime per-step floor for a trust residual.
Intel Core i5-10400T @ 2.00 GHz · rustc 1.90.0 · --release · n = 16.
Detection floor is precision-ordered across ~11 orders of magnitude — the
smallest detectable fault tracks each backend's 2·n·ε_q:
| backend | floor = 2·n·ε_q | min detectable fault | ns / certified step |
|---|---|---|---|
| f64 | 3.55e-15 | 1e-14 | 157.5 |
| fixed Q1.30 | 1.49e-8 | 1e-7 | 195.1 |
| f32 | 1.91e-6 | 1e-5 | 147.9 |
| fixed Q1.14 | 9.77e-4 | 1e-2 | 189.8 |
- No universal threshold: a
1e-7fault is a detected safety event on f64 but below the floor (invisible) on f32 and Q1.14. - Excursion detection: an injected loss of contraction stands
9.5e1×(Q1.14) to2.6e13×(f64) above the floor; flagged at 0-step latency. - Δα term: a mid-transient gate acceleration causes 1 false excursion without
the
|Δα_t|·E_tterm and 0 with it, on every backend. - Throughput 5.1–6.8 M certified steps/s; state vector 64–128 B.
- Not a convergence proof. A clean contraction reaches an exact fixed point (residual → 0); the floor certifies this step's signal-vs-noise, not that the iteration must converge.
- O(1) normalization is assumed. The magnitude-free
2·n·ε_qterm only bounds a float rounding floor when the state is O(1) — the gauge step is what keeps that true (load-bearing, not decorative). - Gate transitions lower sensitivity. The
|Δα_t|·E_tterm is conservative; a real excursion coinciding with a big gate change can fall back toNOT_CERTIFIED(fail-closed-safe). - Abbreviated certificate: this computes the floor + classifier, not endpoint
witnesses or the envelope monitor
B_t.
- Repo: github.com/Hulupeep/ccf
- Research branch:
research/nightly/2026-06-18-runtime-trust-certificate-floor - Crate:
crates/research/runtime-trust-certificate-floor/· Issue: Hulupeep/CCF#165 - Specflow (causation-trail method): github.com/Hulupeep/Specflow
- More on CCF and the shy-robot trust model: floutlabs.com · theshyrobot.com
cargo run --release -p runtime-trust-certificate-floor --bin floor-demo
cargo run --release -p runtime-trust-certificate-floor --bin floor-benchBSL 1.1 → Apache 2.0 in 2032. Contact via floutlabs.com.