Taking the Hendrycks CHC battery as the most precise public score, and reading it against Chollet, Morris, Legg, and METR: the remaining work is not “more knowledge.” It is storage, retrieval discipline, working memory as an object, novel reasoning, and faculties a text lattice cannot fake.
General Knowledge
Kmedium scaffoldBreadth of factual understanding: commonsense, culture, science, social science, history.
- The gap
- Parametric knowledge is wide but stale, uneven, and unowned by a particular life.
- The prosthesis
- Semantic memory plus retrieval tools can hold private, up-to-date facts the weights never saw.
- The limit
- Does not give the model a living world-model; it still quotes rather than inhabits knowledge.
Layers aimed here: Semantic memory, Tool use, World model
Reading & Writing
RWlow scaffoldConsuming and producing written language, from decoding to composition and usage.
- The gap
- Frontier models already match or exceed a well-educated adult on most literacy tasks.
- The prosthesis
- Style constitutions and revision loops polish voice; they do not create literacy.
- The limit
- Long-form consistency still drifts without an external outline.
Layers aimed here: Constitution
Mathematical Ability
Mmedium scaffoldArithmetic through calculus, probability, and formal manipulation.
- The gap
- Symbolic slips persist when the model does arithmetic in prose.
- The prosthesis
- A calculator and program-of-thought tools catch the slips the weights still make.
- The limit
- Novel proof strategy remains a reasoning problem, not a tool problem.
Layers aimed here: Tool use
On-the-Spot Reasoning
Rhigh scaffoldFlexible attention on novel problems: deduction, induction, theory of mind, planning, adaptation.
- The gap
- Fluid intelligence on unseen puzzles (ARC-style) and multi-step plans still collapse without search.
- The prosthesis
- Planner, debate, and reflexion implement System-2 search around the model — the move Claude Code, Deep Agents, and Tree-of-Thoughts all make.
- The limit
- Search over tokens is not Chollet's skill-acquisition efficiency. The model does not get better at the next novel task.
Layers aimed here: Hierarchical planner, Reflexion critic, World model, Metacognition, Skill library, Internal debate, Goal stack
Working Memory
WMhigh scaffoldMaintain and manipulate information in active attention across modalities.
- The gap
- Context windows are a poor working memory: they rot, they are not addressable, they are not operated on.
- The prosthesis
- A scratchpad the agent can read, write, and edit is the standard ACI from SWE-agent onward.
- The limit
- Cross-modal working memory still needs the model's native vision/audio, not a text board.
Layers aimed here: Working memory
Long-Term Memory Storage
MShigh scaffoldContinually learn new information — associative, meaningful, and verbatim. The paper's sharpest remaining zero.
- The gap
- GPT-5 still scores 0. Weights do not update from a conversation. Every session is amnesia.
- The prosthesis
- Episodic and semantic stores (Letta, Mem0, this harness) persist experience outside the weights — the only working prosthetic for MS today.
- The limit
- Hendrycks et al. call this a capability contortion. RAG is not LoRA. The model does not become the memory; it consults it.
Layers aimed here: Episodic memory, Semantic memory, Skill library
Long-Term Memory Retrieval
MRhigh scaffoldFluency and precision of access, including the refusal to confabulate.
- The gap
- Hallucination is a retrieval-precision failure. Search tools hide it without fixing it.
- The prosthesis
- Ground answers in stored memories; metacognition forces a confidence tag when the store is empty.
- The limit
- The generator can still ignore the retrieved note. Precision is a discipline, not a guarantee.
Layers aimed here: Episodic memory, Semantic memory, Reflexion critic, Metacognition
Visual Processing
Vlow scaffoldPerceive, analyze, reason about, generate, and scan visual information.
- The gap
- Scaffolding in text cannot see. Native multimodal models closed some of this; GUIs and spatial scans remain weak.
- The prosthesis
- Computer-use and screenshot loops (Claude managed agents, Operator-class systems) are the visual prosthesis.
- The limit
- This web harness does not embody a pointer. Vision stays a model capability, not a lattice one.
Layers aimed here: none — model-native
Auditory Processing
Alow scaffoldDiscriminate, recognize, and work creatively with speech, rhythm, and music.
- The gap
- Speech I/O is now a product feature; rhythmic and musical judgment are not.
- The prosthesis
- TTS/STT wrap the model. They do not give it an ear.
- The limit
- Out of scope for a text harness. Honest gap.
Layers aimed here: none — model-native
Speed
Smedium scaffoldSimple cognitive tasks quickly: perceptual speed, reaction, number facility, pointer fluency.
- The gap
- Token generation is fast at easy tasks and slow at hard ones; it is not human reaction time.
- The prosthesis
- Tools (calc, clock) and caches make easy operations exact and cheap.
- The limit
- A deliberative lattice makes hard tasks slower on purpose. Speed is not the goal of proto-AGI.
Layers aimed here: Tool use