Latent Bridge: Asking for Help Without Words

Anonymous authors

Frontier-model prefill. Edge-scale decoding.

Sender: Qwen3.8 Max · GLM 5.3 · Deepseek V4 Flash
Receiver: Qwen3.5-4B — a compact, edge-capable model

Sender–receiver collaboration through a latent bridge The same prompt goes to both models. A frontier-scale sender, such as Qwen3.8 Max, GLM 5.3, or Deepseek V4 Flash, performs prefill only. A trainable bridge maps its hidden states to latent attention keys and values for Qwen3.5-4B, a compact receiver capable of running on suitable edge hardware. The receiver generates all output tokens. In this illustrative animation, the prompt asks: If x + 1/x = 3, find x² + 1/x². The original prompt and the bridge's latent keys and values converge on the receiver together, representing joint conditioning rather than exact transfer timing. The receiver then reveals the answer: 9 − 2 = 7. Token boundaries are schematic. Prompt If x + 1/x = 3, find x² + 1/x². Frontier sender Latent bridge 4B receiver Prefill only Hidden states → KV Prompt + latent KV No text generated All output tokens Illustrative token boundaries
The sender helps through latent representations, not an intermediate text response.

Abstract

We introduce POND (Prefill-Only, No-Decode), an architecture that separates large-model prefill from small-model decoding. A frontier-scale sender—Qwen3.8 Max(2.4T), GLM 5.3(753B), or DeepSeek-V4-Flash(284B)—processes the input without generating text. A learned bridge transfers its hidden states as additional attention keys and values to Qwen3.5-4B, a compact receiver capable of running on suitable edge hardware. The receiver generates the complete answer using both the original prompt and the latent guidance. Optional periodic review lets the sender read the partial response and append updated guidance while preserving the receiver’s existing KV cache. Both base models remain frozen; only the bridge is trained.

Selected successful reviews

Inference Examples

A single review can catch a local error, replace a flawed approach, or bring a runaway derivation back to a verified answer.

57/824B baseline
69/82with one GLM draft
70/82best reviewed setting
01Local correctionAIME 2022 · 026

One off-by-one check changes 73 to 72

Connect two of the points numbered 1–20 when their difference is prime. How many triangles are formed?

Before review73

For the twin-prime case p = 11, the span was mistakenly treated as 12, allowing eight starting points.

After one review72

The review catches that the span is p + 2 = 13, so a ≤ 7. Both cases contribute 36.

Improvement Pinpointed and repaired a single off-by-one error · incorrect → correct

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02RecoveryAIME 2023 · 037

A runaway search converges to a verified answer

Find the largest prime p < 1000 satisfying the Gaussian-integer and triangle conditions in the problem.

Before reviewNo answer

The derivation loops while testing whether 977 is a sum of two squares, producing 221,277 characters without a reliable conclusion.

After one review349

With z = 18 + 5i, it obtains x = 4482, y = 4735, and verifies |x − y| = 253 < 349.

Improvement Restored a stalled derivation and reduced output from 221k to 24k characters · incorrect → correct

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Before review · 221k characters

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After review · 24k characters

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03Method revisionAIME 2023 · 047

An incorrect DP gives way to a short counting argument

Place 1–12 in a 2 × 6 grid so adjacent numbers never differ by a multiple of 3. If there are N arrangements, find the number of divisors of N.

Before successful review56 / 546

Complicated state classifications and a faulty dynamic program produce inconsistent, incorrect counts.

After review144

Each residue is omitted by exactly two columns: 6!/(2!2!2!) = 90. Two orientations give 180 residue grids, then N = 180(4!)³.

Improvement Replaced a brittle DP with a compact combinatorial invariant · incorrect → correct

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04Historical review exampleOpenR1-Math-220k

Correct factor structure replaces a broken enumeration

What is the largest k for which 311 is a sum of k consecutive positive integers?

Before review2048

The factor list contains arithmetic errors and even treats non-divisors as factors of 2 · 3¹¹.

After review486

From k(2n + k − 1) = 2 · 3¹¹, the largest valid smaller factor is 2 · 3⁵ = 486; the first term is 122.

Improvement Rebuilt the factor enumeration and produced a directly verifiable construction · labeled improved

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These are selected qualitative successes. The aggregate 82-task results above include all evaluated examples across AIME, MBPP, HumanEval, and LiveCodeBench.