Frontier Forge R1b is a Qwen3.5-4B-Base derivative post-trained to turn a CFPB consumer-complaint narrative plus source metadata into a strict structured triage ticket and one tool call. It is a research artifact for reproducible post-training, serving, and gateway experiments—not a consumer-decision system.

Model variants

Repository subfolder	Contents	Tree SHA-256
`bf16/`	PEFT merge-and-unload, BF16	`7cf43a2905513f61797b78b7e3fd7ebdacd1cba4fc89abea9ce209401e6e6435`
`gptq-int4/`	deployment GPTQ-int4, group size 128, 128 calibration rows	`c99b42cf0e062cc75f2df8588725d0c29383666f3db0c1ae837ce15bfe6d39d2`
`bf16-mtp-preserved/`	merged BF16 plus 15 byte-preserved native `mtp.*` tensors	`7878b55f6fe6a9ecb12b9504b1a88d7bc6fef7ba72d91289b6e8d694f6bc75ce`

The source adapter was trained with NF4 QLoRA. GPTQ is a separate deployment-time quantization step; it is not the training representation. The MTP variant copies the 15 native MTP tensors from the fixed base revision because the language-model-only adapter does not modify them.

Base checkpoint: Qwen/Qwen3.5-4B-Base at revision 1001bb4d826a52d1f399e183466143f4da7b741b.

Intended task and input contract

The input contract is JSON with five fields:

json

{
  "complaint_id": 123,
  "narrative": "consumer complaint text",
  "source_product": "Mortgage",
  "source_issue": "Trouble during payment process",
  "source_company": "Example Company"
}

The output is strict JSON containing normalized product, issue, company, urgency, ambiguity_flag, and exactly one tool_call. Allowed tools are request_more_info, close_no_action, escalate_to_regulator, start_refund_workflow, and route_to_company.

Source metadata is intentionally model-visible. This matches a triage workflow in which upstream intake metadata already exists, but it means the model must not be presented as a leakage-free narrative-only product classifier.

Training

Base: Qwen3.5-4B-Base, pretrained-only checkpoint.
Rung: R1b, one epoch of language-model-only QLoRA SFT.
Training seed: 0; no multi-seed R1b aggregate exists.
Data: 20,000 deterministic rule-labeled TRAIN examples, disjoint from frozen TEST-IID and TEST-DRIFT under a 13-token contamination audit.
LoRA: rank 16, alpha 32, dropout 0; attention and MLP projection targets; visual subtree excluded.
Full-run precision: NF4 QLoRA training, BF16 evaluation.
Hardware/cost: 15.2358 RTX 4090 GPU-hours at the owner-supplied $0.30/hour rate, totaling $4.57075.
Dataset hash: d1092cd16f604c25ed6d5034bf0fed33afbe975af4048fbd2a0cd93d7b25e564.

Evaluation

Frozen evaluation uses 1,000 TEST-IID and 1,000 TEST-DRIFT rows selected with a fixed seed. The primary metric is a hard AND over urgency, ambiguity, tool choice, and structural tool-argument validity. Product/issue/company normalization is secondary and excluded from task success and reward.

Metric	Result
Task success	99.05%
95% bootstrap CI	[98.60%, 99.45%]
Schema validity	100.00%
Tool accuracy	99.15%
Paired gain over 1,450-row R1	+32.70 pp [30.60, 34.50]

Intervals use 1,000 fixed-seed bootstrap resamples over 2,000 frozen examples. The ground truth is the versioned rule policy, not independent human semantic labels.

Serving measurements

On one RTX 4090 with vLLM 0.17.0, native MTP, 4 QPS fixed-seed Poisson arrivals, and 20 measured requests, bf16-mtp-preserved/ recorded:

client E2E p50/p95: 1.063 / 1.311 seconds;
output throughput: 320.6 tokens/second;
verifier success: 95% (19/20);
peak device memory: 21,587 MiB;
cost: $0.0202 per 1,000 verifier-successful tasks at $0.30/GPU-hour.

Native MTP lost the matched p95/throughput gate at 0.25 QPS and won at 0.50, 1, 2, and 4 QPS, with 95.6–96.4% acceptance. These small per-cell serving samples characterize an operating boundary; they do not replace the larger frozen quality evaluation.

The optional C++ gateway measured 0.3% median p50 and 0.5% median p95 overhead across five stable cells. Its overload run has a known defect: errors were admitted requests returning HTTP 502/upstream_error, not designed 429 admission rejects. Non-stable gateway cells had 10–85% errors versus 0% for bare vLLM. Lower success-only p95 in those cells is survivor-biased and is not a model or gateway win.

License and data provenance

The source repository's code is licensed under Apache-2.0.
The released weights are derivatives of Qwen/Qwen3.5-4B-Base at revision 1001bb4d826a52d1f399e183466143f4da7b741b. The upstream model card declares apache-2.0; these variants inherit and are distributed under that same base-model license. Consult the upstream license as well as this card.
Training and evaluation records derive from a byte-frozen snapshot of the CFPB Consumer Complaint Database, whose published data the CFPB describes as freely available to use, analyze, and build on. The source ZIP SHA-256 is b4d1eac8ef9f2e7710224848d321f355c480ff95baa742a2f6d1e3c704705600; the project materialized 571,415 labeled rows while preserving frozen split membership. Narratives in the snapshot were publicly shared only after consumer opt-in and CFPB personal-information scrubbing. Complaints are unverified and are not a representative statistical sample.
No raw CFPB complaint rows are bundled in this Hugging Face model repository. The repository's Apache-2.0 code license does not relicense the CFPB records.

Uses

Appropriate uses:

reproducing the documented structured-output evaluation;
studying rule-label scaling, quantized deployment, native MTP, or constrained generation;
development behind a human-reviewed complaint-triage workflow;
research on LLM-aware gateways, after respecting the documented overload defect.

Out-of-scope uses:

autonomous regulatory, credit, legal, refund, or account actions;
narrative-only product classification claims;
deployment outside the tested English CFPB taxonomy without new evaluation;
handling live personal data without a separate privacy/security review.

Limitations and risks

A deliberately enriched 50-row strong-action stratified sample found 7/50 wrong labels (14.0%), all escalation or refund false negatives. The review balanced changed action transitions, so this is not a population error-rate estimate and is not comparable to the earlier v2 4% figure, which used a different population, protocol, and error opportunity. Evaluation measures fidelity to those rules, so a high score can faithfully reproduce a flawed policy. See results/phase1_2_label_audit.md.
Keyword rules are negation-blind. The single-action taxonomy also prioritizes escalation over refund when both triggers appear.
R2 distilled SFT lost 14.2 points to R1; this is a task-specific result where executable labels are free, not a general rejection of distillation.
The original GRPO runs were invalidated by completion parsing. R4 v2 completed two seeds with a +0.25-point paired delta whose CI included zero; seed 2 hit the locked zero-reward-variance guard. No three-seed aggregate exists.
The TRL/Unsloth agreement gate failed, so TRL is the only reference backend.
No safety, fairness, privacy, memorization, red-team, or human-impact evaluation establishes readiness for autonomous use. Complaint narratives may contain sensitive consumer information.
Serving results are specific to one RTX 4090, vLLM 0.17.0, the declared workload, and the measurement-side definitions in the repository.

Reproduction and provenance

The source repository ships append-only run records, raw serving receipts, failed attempts, export manifests, and a deterministic release chain:

bash

uv sync --locked
make reproduce-headline
make demo-build

The reproduction command makes no new API or GPU call. It rebuilds release payloads from hash-pinned raw artifacts and verifies every publication file by SHA-256.

Key evidence in the source repository:

results/runs.jsonl
results/phase3_paired_deltas.json
results/phase3_export_manifest_r1b_trl_s0.json
results/phase4/r1b_mtp_reexport_manifest.json
results/phase4_serving_report.md
results/phase5_gateway_report.md
results/phase6/source_manifest.json

Citation

If you use the artifact, cite the source repository, the exact Hugging Face commit, the chosen subfolder, and its tree SHA-256. The archive receipt records the remote commit and per-file verification result after publication.

Luciss007/frontier-forge-r1b

Frontier Forge R1b