Large language models struggle to reliably identify and correct errors in their own reasoning. Unlike prior training-based approaches that fine-tune an LLM to generate revisions or feedback, we learn where to intervene in failed rollouts and determine how to redirect them. To choose where to intervene, we train a 130K-parameter MLP head on a frozen encoder using only final-answer correctness. For redirection, we find that under a fixed generation budget, the tested inline injections fail to reliably redirect reasoning, whereas presenting the same instruction in a new user turn changes the model's course. The resulting correction framework, UPTURN (User-Prompt TURN injection at a learned position), requires no LLM fine-tuning: it retains a selected prefix, injects an instruction as a new user turn, and regenerates the suffix. Across four reasoners and six math benchmarks, UPTURN improves average accuracy in every setting over a 32-rollout baseline. It outperforms self-correction and reflection-token injection baselines under matched correction budgets, transfers across reasoners and to GPQA-Diamond without retraining, and complements GRPO and self-correction methods.
Figures & tables
Figure 1: Structure, not content alone, enables redirection. (Left) The same instruction is absorbed inline but redirects reasoning in a new user turn. (Right) Learning where to intervene raises rescue rate (the fraction of failed rollouts corrected; top) and six-benchmark mean accuracy (bottom).
Figure 2: Why turn-boundary injection is needed. (a) Prefix value along failed rollouts, computed as the mean success rate over 16 continuations sampled from each prefix. (b) Position-wise rescue gap R−V for inline (in) and multi-turn (mt) injection, where R is post-injection success and V is prefix value. (c) Oracle best rescue rate obtained by selecting, for each problem and phrase, the position with highest post-injection success.
Figure 3: Overview of UPTURN. (Step 1) A frozen 0.6B encoder and MLP head fϕ score paragraph boundaries ( \n\n ) in failed rollouts ( ✗ ); the policy selects a cut t⋆ . (Step 2) UPTURN retains the prefix, inserts a fixed instruction as a new user turn, and regenerates in a new assistant turn, recovering a correct answer ( ✓ ).
Method
AIME24
AIME25
AIME26
AMC23
HMMT
MATH500
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Qwen3-4B
Base@32
32.6
63.3
21.8
46.7
26.7
43.3
67.0
92.5
19.2
27.3
85.0
93.2
UPTURN@16
50.8
83.3
39.0
56.7
44.2
70.0
84.2
95.0
28.0
39.4
91.0
95.8
Δ
+18.2
+20.0
+17.2
+10.0
+17.5
+26.7
+17.2
+2.5
+8.8
+12.1
+6.0
+2.6
Qwen3-8B
Table 1: Results on six math benchmarks. Base@32 uses 32 rollouts; UPTURN@16 uses 16 rollouts and corrects each gate-flagged one once. Δ denotes UPTURN’s gain over Base; bold marks the higher score.
Self-correction
Reflection-token injection
Budget
Reflexion@16
SCoRe@16
AlphaOne@16
CyclicReflex@16
UPTURN@16
Lmax
43.6 / 61.4
– †
32.6 / 45.2
35.7 / 49.7
59.8 / 77.2 ( +16.2 / +15.9 )
2Lmax
55.3 / 77.5
52.3 / 79.9
55.0 / 71.8
57.2 / 73.5
62.2 / 80.7 ( +4.9 / +0.8 )
Table 2: Comparison with other baselines. Avg / Pass averaged over six benchmarks and all reasoners except QwQ-32B, at two budgets ( Lmax and 2Lmax ). Parentheses give UPTURN’s gain over the best baseline at each budget; bold marks the best scores. † SCoRe requires 2Lmax as it conditions on the full first attempt.
Figure 4: Position-policy transfer. Averages over six benchmarks. (a) Avg gain over Base when the policy trained on the source reasoner is applied to the target; parentheses (and colour) give the difference from the target’s own policy on the diagonal. (b) UPTURN gains over Base and GRPO, averaged over four reasoners; the GRPO setting reuses the corresponding Base-trained position policy without retraining.
Reasoner
Base@32
UPTURN@16
Δ
Avg
Pass
Avg
Pass
Avg
Pass
Qwen3-4B
32.5
56.6
50.4
79.8
+17.9
+23.2
Qwen3-8B
35.0
61.1
54.3
83.8
+19.3
+22.7
DS-R1
20.7
49.0
35.9
78.8
+15.2
+29.8
QwQ-32B
41.5
68.7
54.2
80.8
+12.7
+12.1
Table 3: Transfer to GPQA-Diamond . Δ denotes UPTURN’s gain over Base; bold marks the higher score. DS-R1 abbreviates DeepSeek-R1-Qwen3-8B.
Avg / Pass
Reflexion@16
SCoRe@16
Baseline
55.3 / 77.5
52.3 / 79.9
+ UPTURN
64.1 / 80.5
64.1 / 81.8
Δ
+8.8 / +3.0
+11.8 / +1.8
Table 4: UPTURN after self-correction. Avg / Pass averaged over six benchmarks and three reasoners (excluding QwQ-32B), at 2Lmax . Δ gives the added gain; bold marks the better score in each pair.
Figure 5: Position and injection ablations. Avg and Pass gains over Base@32, averaged over six benchmarks. (a) Fresh regeneration and injection at start, random, or learned positions, using the same gate and replacement rule; averages over four reasoners. (b) Inline and multi-turn injection with separately trained position policies.
Method
Avg
GS
Pass
Base@32
37.1
52.0
53.5
UPTURN@16
55.3
63.0
71.3
Δ
+18.2
+11.0
+17.7
UPTURN@16
55.3
63.0
71.3
UPTURN@16+GT
55.9
63.3
71.3
Δ
+0.6
+0.2
+0.1
Table 5: Gate ablations , averaged over four reasoners and six benchmarks. GS : accuracy of the highest-gate candidate. +GT: flagging with a ground-truth gate.
Appendix figures & tables17 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 6: One failed Qwen3-4B (Thinking on) rollout continued three ways from the same cut. (A) Unmodified continuation remains trapped in re-verification. (B) Inline injection is absorbed as the model’s own reasoning and resumes the loop. (C) The same instruction in a new user turn redirects reasoning to the correct answer. Full rollouts are provided in Appendix .
Hyperparameter
Value
Batch size B (prompts with ≥ 1 failure)
64
Rollouts per prompt N
8
Cut positions per rollout G
8
Continuations per position M
8
Generation budget Lmax
8192
Max generation batches (dynamic sampling)
8
Appendix
Table 6: Hyperparameters
Family (reasoners)
Injected sequence at the cut
Qwen ChatML (Qwen3-4B/8B, QwQ-32B)
<|im_end|>\n<|im_start|>user\n c <|im_end|>\n<|im_start|>assistant\n
DeepSeek (DeepSeek-R1-0528-Qwen3-8B)
<|end_of_sentence|><|User|> c <|Assistant|><think>\n
Appendix
Table 7: Turn-boundary injection sequence per model family. c denotes the fixed instruction.
Benchmark
AIME24
AIME25
AIME26
AMC23
HMMT
MATH500
Avg
AUC
.982
.983
.980
.984
.920
.922
.962
Appendix
Table 8: Gate AUC by benchmark. Mean over four reasoners.
Model
Avg
Pass
Base@32
UPTURN@16
UPTURN@16+GT
Base@32
UPTURN@16
UPTURN@16+GT
Qwen3-4B
42.1
56.2
56.6
61.1
73.4
73.5
Qwen3-8B
41.4
58.3
58.7
60.5
72.7
72.8
DeepSeek-R1-Qwen3-8B
19.2
49.5
50.9
28.8
70.3
70.3
QwQ-32B
45.7
57.2
57.4
63.8
68.7
68.7
Model Avg
37.1
55.3
55.9
53.5
71.3
71.3
Appendix
Table 9: Learned (UPTURN@16) versus ground-truth (+GT) gating , averaged over six benchmarks. Bold marks the higher score; ties are both bold.
γ
0
0.1
0.2
0.4
0.6
0.8
1.0
Avg
37.3
55.6
55.5
55.3
55.2
55.2
55.2
Pass
51.8
71.2
71.3
71.3
71.3
71.3
71.3
Corrected (%)
0
64
69
79
91
99
100
Appendix
Table 10: Sensitivity to the gate threshold γ . Avg and Pass over four reasoners and six benchmarks; Corrected is the fraction of rollouts that receive a correction. Bold marks the default. At γ=0 nothing is corrected.
Method
AIME24
AIME25
AIME26
Avg
GS
Pass
Avg
GS
Pass
Avg
GS
Pass
Qwen3-4B
Base@32
32.6
60.0
63.3
21.8
46.7
46.7
26.7
40.0
43.3
UPTURN@16
50.8
66.7
83.3
39.0
53.3
56.7
44.2
53.3
70.0
Δ
+18.2
+6.7
+20.0
+17.2
+6.7
+10.0
+17.5
+13.3
+26.7
Qwen3-8B
Appendix
Table 11: Gate as a selector , per benchmark. GS is the accuracy of the highest-gate candidate; Avg and Pass are as in Table 1 . Δ denotes UPTURN’s gain over Base; bold marks the higher score.
Method
Gens./q
Gen. tokens/q
Wall-clock (s)
vs. Base@32
Base@16
16.0
122,881
477±2
0.51×
Base@32
32.0
245,548
931±0
1.00×
UPTURN@16
28.6
156,619
790±2
0.85×
Appendix
Table 12: Wall-clock cost on AIME24 (Qwen3-4B, one B200).
Figure 7: Avg and Pass against the number of correction rounds , averaged over six benchmarks. Colour marks the reasoner; solid lines are gated , dashed lines naive .
Figure 8: Avg and rescue rate under varied injection instructions , averaged over six benchmarks. Solid bars are Avg, hatched bars rescue rate; Base has no rescue rate. Instructions are ordered by mean Avg; None inserts the turn boundary with no text.
Boundary entropy
Other entropy
Top-5%
Boundary
Reasoner
mean
median
mean
median
coverage
frac.
Qwen3-4B
0.62
0.61
0.29
0.008
18%
2.0%
Qwen3-8B
0.60
0.59
0.27
0.004
19%
2.0%
DeepSeek-R1-Qwen3-8B
0.99
1.01
0.31
0.018
35%
3.2%
QwQ-32B
0.81
0.80
0.41
0.095
22%
2.6%
Appendix
Table 13: Next-token entropy at \n\n boundaries vs. elsewhere on incorrect AIME24/25 rollouts; coverage is the share of top-5% entropy positions within ±2 tokens of a boundary.
Figure 9: Scaling the generation budget. Avg (top) and Pass (bottom) averaged over six benchmarks as the per-rollout budget grows from Lmax to 3Lmax ; labels give UPTURN’s gain over Base at each budget.
Method
Budget
AIME24
AIME25
AIME26
AMC23
HMMT
MATH500
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Qwen3-4B
Reflexion@16
Lmax
51.5
76.7
36.0
63.3
42.5
66.7
83.9
92.5
25.6
33.3
91.1
96.6
UPTURN@16
Lmax
59.0
83.3
48.3
70.0
53.8
76.7
88.4
97.5
33.9
45.5
92.1
96.4
Δ (vs. best)
+7.5
+6.7
+12.3
+6.7
+11.2
+10.0
+4.5
+5.0
+8.3
+12.1
+1.0
-0.2
Reflexion@16
2Lmax
64.2
86.7
49.0
76.7
55.6
80.0
90.2
100.0
34.3
57.6
93.4
97.8
Appendix
Table 14: Full comparison with self-correction baselines , per reasoner and benchmark, at Lmax and 2Lmax correction budgets. Δ rows give UPTURN’s gain over the best baseline at the same budget; bold marks the best entry per column and budget. SCoRe conditions on the full first attempt, so it is evaluated at 2Lmax only.
Method
Budget
AIME24
AIME25
AIME26
AMC23
HMMT
MATH500
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Qwen3-4B
AlphaOne@16
Lmax
33.8
53.3
21.9
36.7
27.3
46.7
67.0
87.5
16.9
24.2
84.9
92.4
CyclicReflex@16
Lmax
37.7
56.7
25.2
50.0
28.8
46.7
70.2
92.5
19.1
27.3
86.1
92.6
UPTURN@16
Lmax
59.0
83.3
48.3
70.0
53.8
76.7
88.4
97.5
33.9
45.5
92.1
96.4
Δ (vs. best)
+21.2
+26.7
+23.1
+20.0
+25.0
+30.0
+18.3
+5.0
+14.8
+18.2
+6.1
+3.8
Appendix
Table 15: Full comparison with reflection-token injection , per reasoner and benchmark, at Lmax and 2Lmax correction budgets. Δ rows give UPTURN’s gain over the best injection method at the same budget; bold marks the best entry per column and budget.
Method
AIME24
AIME25
AIME26
AMC23
HMMT
MATH500
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Qwen3-4B
Reflexion@16 ( Lmax )
51.5
76.7
36.0
63.3
42.5
66.7
83.9
92.5
25.6
33.3
91.1
96.6
+ UPTURN
49.0
73.3
35.8
53.3
42.5
60.0
84.4
92.5
23.7
33.3
90.9
97.0
Δ
-2.5
-3.3
-0.2
-10.0
+0.0
-6.7
+0.5
+0.0
-1.9
+0.0
-0.3
+0.4
Reflexion@16 ( 2Lmax )
64.2
86.7
49.0
76.7
55.6
80.0
90.2
100.0
34.3
57.6
93.4
97.8
Appendix
Table 16: UPTURN on top of a self-correction baseline , per reasoner and benchmark. Each baseline produces its own 16 corrected solutions; UPTURN’s gate then flags the weak ones among them and redirects each once, at the budget named on the baseline row. Reflexion is shown at both Lmax and 2Lmax ; SCoRe conditions on the full first attempt, so only 2Lmax is meaningful for it. Δ rows give the gain of adding UPTURN; bold marks the better entry of the pair.
Method
AIME24
AIME25
AIME26
Avg
Pass
Avg
Pass
Avg
Pass
Qwen3-4B
Base@32
33.4 ± 0.8
62.2 ± 1.9
21.6 ± 0.2
47.8 ± 1.9
26.1 ± 1.2
43.3 ± 0.0
UPTURN@16
52.1 ± 1.1
81.1 ± 3.8
40.0 ± 1.0
58.9 ± 1.9
45.8 ± 1.5
70.0 ± 0.0
Δ
+18.7
+18.9
+18.4
+11.1
+19.7
+26.7
Qwen3-8B
Appendix
Table 17: Seed robustness. Table 1 repeated with three seeds for training the position policy and drawing rollouts; mean ± std over the three runs. Δ is UPTURN’s gain; bold marks the higher mean.
Method
AIME24
AIME25
AIME26
AMC23
HMMT
MATH500
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
Avg
Pass
AceReason-Nemotron-1.1-7B
Base@32
37.2
73.3
27.7
40.0
31.5
56.7
79.7
95.0
19.5
30.3
88.4
96.2
UPTURN@16
47.5
73.3
32.5
46.7
44.6
63.3
89.7
95.0
27.1
45.5
92.1
97.0
Δ
+10.3
0.0
+4.8
+6.7
+13.1
+6.7
+10.0
0.0
+7.6
+15.2
+3.7
+0.8
Skywork-OR1-7B
Appendix
Table 18: Results on two additional reasoners , with the same setup as Table 1 . Δ denotes UPTURN’s gain over Base; bold marks improvements.
Department of Electrical and Computer Engineering & Ingenuity Labs, Queen’s University · Conflict Analytics Lab, Queen’s University · Cornell Law School +1