Research
SVAF
Per-Field Memory Evaluation for Multi-Agent Systems
Core Insight
A coding agent and a fitness agent are cognitively distant — their hidden states diverge. Peer-level coupling would reject signals between them. But when the coding agent observes “user sedentary 2 hours, exhausted”, the fitness agent needs to hear it. The signal’s mood and issue fields are directly relevant; its focus field (debugging auth module) is not. Scalar similarity produces one ambiguous score. SVAF evaluates each field independently and decides: absorb the relevant dimensions, suppress the irrelevant ones, synthesize a new memory that reflects both the incoming signal and local context.
Two-Level Coupling
The Mesh Memory Protocol evaluates signals at two levels. Both are necessary. Neither is sufficient alone.
| Level | Question | Operates on | Mechanism |
|---|---|---|---|
| Peer-level | Is this agent cognitively aligned with me? | CfC hidden states | Kuramoto phase coherence |
| Content-level (SVAF) | Is this specific memory relevant to me? | CMB fields | Per-field drift + fusion gate |
Claude Code → sym_remember("user sedentary 2hrs, exhausted")
→ CMBEncoder decomposes into 7 fields
→ broadcast to mesh peers
MeloMove receives:
→ peer drift: 1.05 (coding ≠ fitness — rejected at peer level)
→ SVAF per-field evaluation:
mood: "exhausted, low energy" → relevant (high gate)
issue: "sedentary 2 hours" → relevant (high gate)
focus: "debugging auth module" → irrelevant (low gate)
→ content ACCEPTED — field-level relevance overrides peer rejection
→ fusion produces NEW CMB for MeloMove's local memory
→ MeloMove synthesizes recovery workout recommendationWithout two-level coupling, the fitness agent either accepts everything from the coding agent (noise) or rejects everything (misses critical health signals). SVAF makes the distinction that scalar evaluation cannot.
Why Scalar Evaluation Fails
A signal with highly relevant mood but irrelevant focus produces a moderate cosine similarity score. The score may or may not cross the threshold — depending on incidental vector interactions, not semantic relevance. The decision is brittle and uninterpretable: the agent cannot explain which dimensions drove acceptance or rejection.
| Property | Scalar Evaluation | SVAF |
|---|---|---|
| Granularity | One score for entire signal | 7 independent per-field scores |
| Decision basis | Threshold on aggregate | Per-field drift profile |
| Output | Accept or reject (binary) | Aligned / guarded / rejected + per-field gate values |
| Interpretability | None | Which fields drove the decision, and by how much |
| Cross-domain | Fails when relevant and irrelevant dimensions coexist | Absorbs relevant fields, suppresses irrelevant ones |
How SVAF Works
SVAF operates on Cognitive Memory Blocks — each memory signal decomposed into 7 typed semantic fields (CAT7 schema). The evaluation pipeline has four stages:
Each CMB field is encoded by a shared backbone with per-field projection heads. The focus head learns a different subspace from the mood head.
Fields within a CMB attend to each other via cross-field attention. Energy affects mood interpretation. Perspective modulates issue interpretation.
For each field, the incoming vector is compared against local anchor memory. Per-field drift scores quantify divergence. A learned fusion gate determines how much of each field to accept.
Accepted fields are fused with local context through non-linear transforms. The output is a NEW CMB — not the original, not a copy, but a synthesized memory shaped by the receiver’s domain intelligence.
Per-field fusion gate:
gf = gate(incoming, local, τfresh, confidence) ∈ [0, 1]
gf → 1: accept incoming field gf → 0: keep local context
The gate values provide per-field interpretability: for any fusion event, you can inspect which fields were absorbed from the incoming signal and which were replaced by local context. This is the auditability that scalar evaluation cannot provide.
Per-Agent Temporal Drift
The same signal has different temporal relevance depending on the receiver. SVAF conditions the fusion gate on a per-agent temporal freshness factor:
MeloTune
Current mood for playlist — stale mood is wrong music
Claude Code
Session context — yesterday’s debugging is irrelevant
MeloMove
Sedentary detection needs hours of context
Knowledge
Daily digest cycle
A coding agent’s “user exhausted after 8 hours” is relevant to the music agent for 30 minutes (adjust the playlist) but relevant to the fitness agent for 3 hours (sedentary pattern detection). Same signal, same content drift, but different temporal drift based on the receiver’s domain needs.
Cross-Domain Relevance
Not all CMB fields carry equal value across domain boundaries. SVAF encodes a minimal hypothesis: mood (affective state) has higher cross-domain relevance than other fields. A fitness agent, a music agent, and a coding agent all benefit from knowing the user’s emotional state. Domain-specific fields (what exactly the user is coding) stay sovereign.
The fusion gate is trained with a soft ordering constraint — for accepted signals, the mood gate should exceed the mean of other field gates. This is the only supervision on gate values. The specific gate magnitudes and the relative ordering of other fields emerge from the decision and drift objectives alone.
Key principle SVAF does not prescribe which fields matter for which agent. Per-agent field weights (αf) are defined by each agent type — see Cognitive Memory Blocks. SVAF provides the mechanism for per-field evaluation. The policy is defined by each receiver autonomously.
Where SVAF Fits the Stack
Layer 7 APPLICATION Domain Agents ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ Layer 6 xMesh Per-agent LNN (coupled CfC) ┐ Layer 5 SYM Synthetic Memory ├ Mesh Cognition Layer 4 COUPLING Drift · SVAF ← you are here ┘ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ Layer 3 MEMORY L0 · L1 · L2 Layer 2 CONNECTION Handshake · Gossip Layer 1 TRANSPORT IPC · TCP · WS · Push Layer 0 IDENTITY nodeId · keypair
Full data flow:
OUTBOUND (agent → mesh):
Agent observation → CMBEncoder (7 CAT7 fields) → CMB
→ broadcast via MMP (Layer 1–2)
→ stored as L1 memory (Layer 3)
INBOUND (mesh → agent):
→ SVAF evaluates per field (Layer 4)
→ per-field drift: which fields are relevant?
→ fusion gate: how much of each field to accept?
→ decision: aligned / guarded / rejected
→ if accepted: fusion produces NEW synthesised CMB
BOTH flows feed agent’s own xMesh LNN (Layer 6):
→ SYM encodes CMBs → CfC hidden state (Layer 5)
→ agent’s CfC evolves cognitive state from own + mesh CMBs
→ h1, h2 broadcast to peers (state-sync)
→ agent acts → remember() → new outbound CMB → loopSVAF is the gatekeeper. Nothing enters xMesh without passing per-field evaluation. This is by design: the quality of collective intelligence depends entirely on the quality of what enters the collective.
Training
SVAF is trained end-to-end on LLM-authored multi-agent narrative scenarios — temporal stories capturing realistic interaction patterns across 20 agent types in 8 domains. Each narrative is a sequence of timestamped signals from different agents, telling a coherent causal story about a user’s state evolution.
| Parameter | Value |
|---|---|
| Model parameters | 604K |
| Training samples | 237,120 (273 narratives, 20 agent types) |
| Field schema | CAT7 (7 fields) |
| Encoder | all-MiniLM-L6-v2 (384-dim) |
| Model size | 2.3 MB |
Per-field drift ground truth comes from independently annotated field relevance scores — not computed from the model’s input embeddings. Gate values emerge from the decision and drift objectives with minimal supervision. Full training methodology in the forthcoming paper.
Related
Cognitive Memory Blocks — the data structure SVAF operates on (7 CAT7 fields)
Synthetic Memory — the transformation layer that encodes fused CMBs into xMesh input (Layer 5)
Mesh Memory Protocol — the protocol stack including SVAF at Layer 4
Mesh Cognition — the theoretical framework for coupled CfC dynamics
Intellectual Property
SVAF is original work by Hongwei Xu and SYM.BOT Ltd. The following remain proprietary: trained neural models and training procedures, field encoder architecture, fusion gate internals, production configurations, and domain-specific product integrations.
Academic citation of this work is permitted and encouraged.
For partnership inquiries: info@sym.bot
SVAF, Cognitive Memory Blocks, Mesh Memory Protocol, SYM, Synthetic Memory, Mesh Cognition, xMesh, MeloTune, and MeloMove are trademarks of SYM.BOT Ltd. © 2026 SYM.BOT Ltd. All Rights Reserved.