M-Stack wraps any model with a metacognitive layer that can monitor uncertainty, verify claims, and choose to abstain when evidence is weak, converting raw capability into auditable reliability.
Benchmark figures on this page are illustrative demo data showing the evaluation methodology, not independently measured results.
What is M-Stack?
A four-layer reliability architecture, Monitor → Evaluate → Control → Learn, that supervises generation, scores quality and grounding, chooses actions (verify, revise, abstain, emit), and adapts its thresholds over time.
Monitor
Entropy, disagreement, and contradiction checks identify risky outputs before they escape.
Evaluate
Judge/PRM scoring plus citation alignment to detect unsupported claims in RAG.
Control
CMDP policy enforces risk caps and budgets: verify, abstain, or emit with a rationale.
Live M-Stack Demo
See M-Stack in action. Compare base model hallucinations to M-Stack’s abstentions and verifications.
Scenario: The model is asked a question that requires information from retrieved documents. The Base model may synthesize an answer even if it's not directly supported, while the M-Stack enforces a citation gate.
Retrieved Document (Wikipedia Snippet):
[S1] The Eiffel Tower is a wrought-iron lattice tower on the Champ de Mars in Paris, France. It is named after the engineer Gustave Eiffel, whose company designed and built the tower from 1887 to 1889.
Base Model
M-Stack
Scenario: The model is asked a question where the answer is not present in the provided context. The Base model may attempt to answer anyway (hallucinate), while the M-Stack should abstain.
Context:
The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the one-mile-wide strait connecting San Francisco Bay and the Pacific Ocean. Its construction began on January 5, 1933.
Base Model
M-Stack
Scenario: Given a set of items with different predicted correctness scores, the controller must decide which to emit to stay under a risk budget (e.g., max 20% error). It plots a simple Risk-Coverage curve.
Max allowed error among emitted items
Controller Output
Risk vs. Coverage
Artificial Metacognition: A Reliability Architecture for Frontier AI Systems
An Industry Framework for Auditable AI Reliability • Version 1.2
1 Executive Summary
Scale has delivered breathtaking capability. Trust requires a second ingredient: systems that know when to slow down, look again, or ask for help. Metacognition is that ingredient.
We present M-Stack, an inference-time reliability layer that monitors uncertainty and contradiction, evaluates quality and grounding, controls actions (verify, revise, abstain, emit), and learns thresholds over time, with additions for risk guarantees (RCC), conformal citation-gated RAG, process supervision, and cost-aware constrained control.
Evidence Preview. Our evaluation plan establishes hallucination reduction and improved risk-coverage at matched cost against strong baselines, with RCC curves and conformal calibration providing guarantees on error@coverage.
2 The Concept: Artificial Metacognition
Artificial Metacognition surrounds a model with a closed-loop control system that supervises and intervenes during inference.
3 Related Work & Comparative Analysis
We position M-Stack beyond post-hoc calibration and selective prediction by making uncertainty actionable (verify/revise/abstain) and auditable (logs, traces, and guarantees).
4 The M-Stack Architecture
4.0 Overview
Training-agnostic control with four layers: Monitor, Evaluate, Control, Learn.
Four-part M-Stack loop operating around a core model.
4.1 Control as a Constrained Optimizer (CMDP)
M3 maximizes selective utility under constraints: risk cap (error@coverage ≤ α) and cost caps (tokens/latency).
# Lagrangian objective (per domain/route)
maximize E[U(a; x)] - λ · (cost(x,a) - B) - μ · (risk(x,a) - α)
update λ, μ via dual ascent; tune thresholds for verify/abstain/emit.
Why: Replaces brittle rules with tunable guarantees. Ops can dial budgets and target error rates.
4.2 Process Supervision & Statement-Graph Contradiction
M2 adds a process reward model (PRM) that scores steps; M1 builds a claim graph across K samples using NLI edges. M3 emits when a consistent subgraph meets score, otherwise verify/revise.
# Weighted aggregation (Dawid-Skene style)
# estimate path reliabilities and weight candidates before fusion
5 MetaBench: Benchmarking Metacognition
We evaluate accuracy, calibration (ECE, meta-d′), risk-coverage (AURC), RCC (guaranteed risk at coverage), hallucination rate, and abstention quality.