TeachMateGPT: A Multi-Agent Knowledge-Grounded Framework for Pedagogical Assessment Generation from Science Curriculum Materials
Organizations: Ahsanullah University of Science and Technology, Bangladesh · American International University - Bangladesh · Jashore University of Science and Technology, Bangladesh
Abstract
Automatically generating textbook-grounded assessment items can reduce science teachers' workload, but existing retrieval-augmented generation (RAG) systems rely on flat retrieval, support only single-question generation, lack safeguards against weak evidence, and are ill-suited to low-resource, board-exam-structured curricula. We address these limitations with TeachMateGPT, a multi-agent system contributing four advances to curriculum-grounded science-assessment authoring. (i) COPE, a hierarchical knowledge base replacing token-window chunking with a multi-resolution index that segments documents along syllabus structure and links them at three granularities via a traversable graph-based lineage, matching evidence to each topic's instructional level. (ii) A staged, fail-closed agent pipeline replacing one-shot retrieve-then-generate: routing gates search, retrieval fuses dense and lexical evidence under a coverage gate that withholds generation on insufficient evidence, and specialist agents draft objective and constructed-response items. (iii) SAVER, a source-attributed verification protocol scoring faithfulness, relevance, and hallucination risk against retrieved evidence, applying stricter grounding checks across each creative question's four sub-parts, paired with teacher-in-the-loop evaluation rather than automatic filtering. (iv) NCTB-SciGen8, a curriculum-grounded dataset of 198 items (143 multiple-choice, 55 creative questions) spanning all 14 chapters of the NCTB Class 8 science textbook, produced by the pipeline and rated by three practicing teachers. TeachMateGPT raises faithfulness (0.68 0.96) and answer relevancy (0.60 0.89) over a vanilla RAG baseline.
Figures & tables
| Configuration | Faith. | Ans. Rel. | Ctx. Prec. | Ctx. Rec. |
|---|---|---|---|---|
| Vanilla RAG | 0.68 | 0.60 | 0.54 | 0.58 |
| TeachMateGPT | 0.96 | 0.89 | 0.92 | 0.91 |
| w/o COPE | 0.86 | 0.76 | 0.73 | 0.75 |
| w/o SAVER | 0.79 | 0.86 | 0.90 | 0.89 |
| w/o CCR | 0.83 | 0.81 | 0.84 | 0.85 |
| w/o CCI | 0.84 | 0.82 | 0.85 | 0.86 |
| Configuration | Pedagogical Alignment | Stimulus Realism | Linguistic Fluency | Overall Utility |
|---|---|---|---|---|
| Vanilla RAG | 2.40 0.12 | 1.75 0.10 | 3.00 0.12 | 2.00 0.10 |
| TeachMateGPT | 4.90 0.10 | 4.70 0.10 | 4.60 0.10 | 4.80 0.10 |
| w/o COPE | 4.05 0.10 | 3.90 0.12 | 4.35 0.08 | 3.95 0.10 |
| w/o SAVER | 3.25 0.12 | 4.25 0.10 | 4.25 0.10 | 3.55 0.12 |
| w/o CCR | 3.80 0.10 | 4.05 0.10 | 4.30 0.08 | 3.95 0.10 |
| w/o CCI | 3.75 0.10 | 4.00 0.10 | 4.25 0.10 | 3.85 0.10 |
Appendix figures & tables16 assets
Supplementary material from the paper’s appendix.
Appendix
| Quantity | Value |
|---|---|
| Chapters ingested | 14 / 14 |
| Total chunks | 793 |
| Macro-tier chunks | 181 |
| Meso-tier chunks | 255 |
| Micro-tier chunks | 357 |
| Token-aligned micro tier | disabled |
| Ch. | Chapter Name (Bangla) | Chapter Name (English) | Pages | MCQ | CQ | Subject |
|---|---|---|---|---|---|---|
| 1 | pRaiNjgetr eshRiNibnYas | Classification of Animal Kingdom | 1–12 | 13 | 4 | Biology |
| 2 | jiiebr brRid/dh O bNNGshgit | Growth & Heredity of Organisms | 13–23 | 11 | 4 | Biology |
| 3 | bYapn, AibhsRbN O pResWdn | Diffusion, Osmosis & Transpiration | 24–33 | 10 | 4 | Biology |
| 4 | Uid/bhedr bNNGsh brRid/dh | Reproduction in Plants | 34–44 | 10 | 4 | Biology |
| 5 | smnWJ O inhsrN | Coordination & Excretion | 45–54 | 9 | 4 | Biology |
| 6 | prmaNur gThn | Structure of the Atom | 55–64 | 11 | 4 | Chemistry |
| No. | Validation Gate | Pass rate | What it checks |
|---|---|---|---|
| 1 | MCQ: exactly 4 options + valid answer index + Bangla-dominant stem/options | 137/143 = 95.8% | Structural well-formedness |
| 2 | MCQ: Bangla-dominant text 0.55 ratio | 143/143 = 100% | Language-purity of item text |
| 3 | CQ: starts with “Ud/diipk:” + narrative + not a theory-dump | 55/55 = 100% | Board-style stimulus framing |
| 4 | CQ: 5 sentences in the “Ud/diipk” story | 55/55 = 100% | Narrative sufficiency |
| 5 | CQ: not a direct theory-dump opener | 55/55 = 100% | Anti-extractive framing |
| 6 | CQ: 0.85 Bangla-only ratio, no non-Bangla letters | 52/55 = 94.5% | Language-purity of item text |
| Intent label | Count | % | Terminates without retrieval? |
|---|---|---|---|
| Science query | 21 | 70% | No |
| Greeting | 3 | 10% | Yes (all 3 pure greetings) |
| Harmful | 3 | 10% | Yes (fixed reply) |
| Off-topic | 3 | 10% | Yes (fixed reply) |
| Metric | Value |
|---|---|
| Deterministic guard accepts as non-ambiguous | 17 (81%) |
| Model judges non-ambiguous | 1 (5%) |
| Model judges ambiguous, guard overrides | 0 (0%) |
| Ambiguous - clarification triggered | 3 (14%) |
| Clarification rate (of full bank) | 3/30 = 10% |
| Over-clarification rate (exam-style prompts wrongly flagged) | 0/16 = 0% |
| Field | Type | Description |
|---|---|---|
| question_id | string | Unique assessment identifier |
| query | string | Teacher query text |
| selected_tasks | list | Requested assessment families |
| chapter | string | Detected chapter label |
| concept | string | Detected concept label |
| sources | list | Retrieved textbook evidence sources |
| Configuration | Fail-closed rate | Coverage ratio | Notes |
|---|---|---|---|
| TeachMateGPT (dense + BM25 + CCI + CCR + coverage gate) | 12.5% (2/16) | 0.724 | Default configuration |
| Dense-only | 31.3% (5/16) | 0.618 | Lexical evidence often missed without BM25 |
| BM25-only | 18.8% (3/16) | 0.682 | Semantic matches frequently unavailable |
| w/o CCI | 18.8% (3/16) | 0.701 | Inconsistent retrieved evidence occasionally reduced support |
| w/o CCR | 18.8% (3/16) | 0.705 | Duplicate chunks lowered effective evidence diversity |
| w/o coverage gate | 0.0% (0/16) | 0.649 | All queries answered regardless of evidence sufficiency |
| Configuration | Mean LLM Calls / Query | Mean Latency (s) | Queries Generating | One-Time Index LLM Calls | Index Build (s) |
|---|---|---|---|---|---|
| TeachMateGPT | 2.1 | 11.3 | 3 / 16 | 0 | 0 |
| Vanilla RAG | 1.0 | 39.8 | 16 / 16 | 0 | 0 |
| w/o IAC | 1.8 | 26.3 | 9 / 16 | 0 | 0 |
| RAPTOR | 1.0 | 42.3 | 16 / 16 | 66 | 224.3 |
| GraphRAG | 1.4 | 46.7 | 16 / 16 | 82 | 287.5 |
| CRAG | 2.2 | 39.0 | 16 / 16 | 0 | 0 |
| Prior Work | Lang. | CAR | Multi-Agent | Evidence Verification | Multi-Format Generation | PD+HV |
|---|---|---|---|---|---|---|
| N et al. (2025) | EN | ✗ | ✗ | ✗ | MCQ | ✗ |
| Hamidi et al. (2025) (JAIT) | EN | ✗ | ✗ | — | MCQ + QA | ✗ |
| Duan et al. (2026) (CODE-GEN) | EN | ✗ | ✓ | ✓ | MCQ | — |
| Chen and Shiu (2025) (KAQG) | EN | — | ✓ | ✓ | MCQ | ✗ |
| Tian and others (2026) (ReQUESTA) | EN | ✗ | ✓ | ✓ | MCQ | — |
| Khan and Khan (2025) (B-RAG) | BN | — | ✗ | — | QA only | ✗ |
| Metric | MCQ | CQ |
|---|---|---|
| Mean items generated / target | 5 / 5 | 1 / 1 |
| % turns satisfied by strict pass (attempt 1) | 12/14 = 85.7% | 14/14 = 100% |
| % turns requiring relaxed pass | 2/14 = 14.3% | n/a |
| Difficulty | n | Mean stem length | Reasoning-depth rating |
|---|---|---|---|
| Beginner | 116 | 53.2 | Low: direct recall/definition (“kii”, “kaek bel”, “ekaniT”) |
| Intermediate | 11 | 52.7 | Medium: comparison/explanation (“par/thkY”, “ekn”, “bYakhYa”) |
| Advanced | 16 | 55.9 | Medium-high: numeric/multi-step reasoning (“inr/Ny kera”) |
| Metric | MCQ ( ) | CQ ( ) | All items ( ) |
|---|---|---|---|
| Faithfulness (spot-checked 15 items / all 55 CQ clues) | 0 errors found | 0 fabricated facts found | 0 factual errors found |
| Answer relevance (on-topic by construction) | 143/143 | 55/55 | 198/198 |
| Hallucination risk (invented specifics) | None identified | None identified | None identified |
| Format/structural risk | 6/143 fail strict gate | 3/55 fail Bangla-only ratio | 9/198 total (6 MCQ format + 3 CQ notation) |
Automated Test Generation
Automated test generation creates inputs, scenarios, and checks to expose software and system defects with less manual effort.
See all 125 papers