External-memory systems extend language-model applications beyond a context window, but their quality depends critically on the model executing the write path: deciding what to retain, how precisely to represent it, and how new evidence should update persistent state. Existing frameworks typically place a general-purpose large language model behind framework-specific prompts. This raises serving cost, and a writer specialized for one protocol does not transfer directly to another; a unified model that can operate across established memory frameworks remains largely unexplored. We present Hy-Memory-30B-A3B, a compact long-term-memory writer trained across Mem0, MemOS, and Hy-Memory. Memory On-Policy Distillation teaches framework-specific write protocols on student-generated states; Memory RL then optimizes downstream answerability using dense per-chunk probes, attributed cross-chunk rewards, over-storage controls, and chunk-level GRPO. Carrying policy-written banks across windows keeps training aligned with deployment. On fixed 20% benchmark subsamples, Hy-Memory-30B-A3B ranks first on all four evaluated harnesses, including held-out EverMemOS, with a 55.49% macro average versus 54.62% for Claude Opus 5.
Figures & tables
Method
Learned policy and environment
Reward and distinction
Memory-R1
Manager and answer agent over a structured external bank
Downstream answer outcome; writer is confounded with the learned reader
MemAgent
Recurrent writer and answer policy over model-native fixed memory
Terminal score broadcast over the trajectory; not a drop-in writer
Mem- α
Construction policy over a custom multi-component bank
Global QA plus local checks; global correctness is shared across actions
MemCoE
Guideline and evolution policy for personalization memory
Process plus final-answer reward; checks guideline adherence rather than evidence contribution
Hy-Memory-30B-A3B
Writer only, operating in Mem0, MemOS, and Hy-Memory
Per-chunk recall, attributed outcome, and growth penalty; localizes evidence to writes
Table 1: How Hy-Memory-30B-A3B differs from prior memory RL.
Family
Configuration
Role
Mem0
General
Incremental extraction and additive writing
MemOS
General
Multi-stage extraction and reconciliation
Hy-Memory
Chat
Personal conversational memory
Hy-Memory
Working
Tasks, decisions, and project state
Hy-Memory
Coding
Code, commands, bugs, and technical decisions
Table 2: Harness families and scenario configurations.
Figure 1: Hy-Memory-30B-A3B is trained inside the same deployed harness configurations in both stages. OPD supplies dense teacher supervision on student-written state chains; RL examines the resulting banks, assigns chunk-level credit, and carries the selected bank across windows. In the rollout grid, each cell is the bank after chunk t of rollout i , shaded by its chunk score si[t] . Advantages are normalized within each column (dashed: one chunk-level group), so the best rollout can differ from chunk to chunk. The outlined cell is the final bank with the highest ∑tsi[t] , which becomes the parent of the next window.
Pass
Annotator context
Output and target
Per-chunk probe (PRM)
Full text of chunk t plus facts of chunks t−1 and t−2
Atomic facts, probes, traps, and rubrics; tests whether chunk t was written precisely and remains recoverable
Cross-chunk outcome (ORM)
Earlier-sequence facts plus all facts in the current window
Questions, evidence chunks, gold facts, and rubrics; tests relations spanning chunks or sessions
Table 3: The two annotation passes and the reward each one feeds.
Figure 2: Construction of the Memory RL reward artifact. Each session is split independently into chunks of about ten turns, so chunks never cross session boundaries. The chronological chunk stream is then grouped into RL windows of at most five chunks; a window may span sessions. The per-chunk probe pass writes the PRM items for chunk t . It reads the full text of chunk t plus the extracted facts of chunks t−1 and t−2 , used only to resolve references and decide what is new. The cross-chunk outcome pass writes ORM items from the facts of the whole window and earlier history. Structural filters and a synthetic-answer discriminability test produce the final artifact. The bottom row lists the rules that keep answer information out of the reward path (Section 5.6 ).
Probe type
What the reward tests
Specificity
Exact names, numbers, titles, versions, paths, and entities survive writing
Semantic precision
Negation, scope, and event meaning are not inverted
Plain recall
A durable explicit fact remains answerable
Secondary dimension
A dominant topic does not erase a smaller detail
Transition
The new state and the state it supersedes are both represented
Should-not-store
Greetings, vague praise, and generic assistant text are absent
Table 4: Per-chunk failure-surface probes.
Configuration
Processed units
Reward items
Hy-Memory / Chat
3,182 windows; 14,519 chunks
41,990 recall; 2,769 traps; 15,281 ORM
Hy-Memory / Working
1,971 windows; 8,902 chunks
25,272 recall; 1,537 traps; 9,740 ORM
Hy-Memory / Coding
1,154 windows; 5,187 chunks
14,348 recall; 178 traps; 5,337 ORM
Mem0
3,182 windows; 14,516 chunks
41,416 recall; 1,969 traps; 15,228 ORM
MemOS
3,182 windows; 14,492 chunks
41,550 recall; 2,146 traps; 15,241 ORM
Total
12,671 windows; 57,616 chunks
164,576 recall; 8,599 traps; ∼ 60.8k ORM
Table 5: Harness-level statistics of the RL reward artifact.
Figure 3: Cross-harness macro-average scores on the fixed 20% benchmark matrix. Each harness score averages six metrics equally; Overall averages the four harnesses equally. EverMemOS is held out from training.
Memory writer
Mem0
Hy-Mem.
MemOS
EverMem.
Avg.
Hy-Memory-30B-A3B
54.02
60.55
50.51
56.89
55.49
Claude Opus 5
53.43
60.53
50.50
54.04
54.62
DeepSeek V4.1 Flash
49.73
60.20
49.17
55.47
53.64
Hy3
45.99
58.06
50.19
52.30
51.63
Qwen3.6-35B-A3B
47.51
55.87
47.36
50.75
50.37
Hy3-A3B Base
40.20
50.39
49.05
50.98
47.66
Table 6: Six-metric means on fixed 20% benchmark subsamples. The macro average weights the four harnesses equally.
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
Writer
LoCoMo
LME
PM-v2
Travel
Shop.
CMB
Avg.
Hy-Memory-30B-A3B
59.54
73.00
51.62
54.51
18.33
67.13
54.02
Claude Opus 5
69.47
66.00
53.58
42.98
17.78
70.74
53.43
DeepSeek V4.1 Flash
58.78
69.39
49.56
35.07
16.67
68.92
49.73
Hy3
41.22
62.00
44.44
46.87
17.22
64.16
45.99
Qwen3.6-35B-A3B
50.00
69.00
49.38
36.39
20.00
60.30
47.51
Hy3-A3B Base
50.00
47.00
40.82
37.91
14.44
51.03
40.20
Appendix
Table 7: Detailed results on the Mem0 harness.
Writer
LoCoMo
LME
PM-v2
Travel
Shop.
CMB
Avg.
Hy-Memory-30B-A3B
73.28
89.00
51.54
57.65
21.11
70.73
60.55
Claude Opus 5
74.43
89.69
48.71
51.34
23.33
75.70
60.53
DeepSeek V4.1 Flash
72.90
85.86
49.00
53.46
22.78
77.18
60.20
Hy3
69.47
89.00
52.76
49.01
21.67
66.44
58.06
Qwen3.6-35B-A3B
70.99
84.85
43.56
49.82
20.00
65.98
55.87
Hy3-A3B Base
66.41
87.00
49.84
31.36
17.78
49.97
50.39
Appendix
Table 8: Detailed results on the Hy-Memory harness.
Writer
LoCoMo
LME
PM-v2
Travel
Shop.
CMB
Avg.
Hy-Memory-30B-A3B
62.98
73.00
51.92
24.15
21.11
69.91
50.51
Claude Opus 5
63.74
79.38
52.84
22.14
19.44
65.46
50.50
DeepSeek V4.1 Flash
61.07
73.00
50.68
18.61
21.67
69.97
49.17
Hy3
62.98
81.00
49.64
18.87
18.89
69.78
50.19
Qwen3.6-35B-A3B
55.34
79.00
51.34
20.08
15.56
62.82
47.36
Hy3-A3B Base
58.40
73.00
50.86
26.05
21.11
64.88
49.05
Appendix
Table 9: Detailed results on the MemOS harness.
Writer
LoCoMo
LME
PM-v2
Travel
Shop.
CMB
Avg.
Hy-Memory-30B-A3B
73.28
76.00
53.28
56.56
19.05
63.19
56.89
Claude Opus 5
73.28
80.41
51.19
45.91
23.89
49.53
54.04
DeepSeek V4.1 Flash
72.52
82.83
49.74
59.47
18.89
49.38
55.47
Hy3
68.70
83.00
48.68
46.52
19.44
47.44
52.30
Qwen3.6-35B-A3B
69.08
79.00
50.60
43.53
18.77
43.52
50.75
Hy3-A3B Base
64.50
81.00
52.14
41.74
20.56
45.93
50.98
Appendix
Table 10: Detailed results on the held-out EverMemOS harness.
Stage 1: OPD
Stage 2: RL
Model
Hy3-30B-A3B
Hy3-30B-A3B
Init.
Instruction-tuned
OPD step 375
Harnesses
Mem0, MemOS, Hy-Memory
Same
Ordering
Snapshot chain
Chronological windows
Unit
One chunk write
One window, ≤ 5 chunks
Rollouts
2 per row
8 per window
Appendix
Table 11: Training hyperparameters for the two stages.
Memory-augmented language models combine persistent or temporary memory with neural computation to retain, retrieve, and use information beyond the active context.