# Preprints.ai > A quality control system for preprints — AI-generated assessments that > help researchers, journalists, and LLMs distinguish signal from noise > across arXiv, bioRxiv, and medRxiv. ## What this is Preprints.ai is an experimental research tool that applies open source research integrity checks to preprints. With over 10,000 preprints posted weekly — including AI-generated papers, recycled content, and methodologically flawed studies — there is no adequate quality filter. Preprints.ai provides a first-pass filter using automated scoring. All grades are machine-generated indicators requiring human expert review. This platform assists but does not replace traditional peer review. ## How it works 1. Submit a preprint by DOI, arXiv ID, or bioRxiv/medRxiv URL 2. An eleven-agent panel (mixed Claude / local Ollama models, including a positive-evidence reviewer) independently reviews the full paper. Worker policy: full text required; abstract-only papers are deferred, not graded. 3. Each reviewer emits a structured review including evidence_strength (one of five labels) and significance (one of five labels) 4. A deterministic lookup derives a 2-axis grade (A-E × 1-5) and then a single 10-tier Publication Fit score anchored to real journals 5. Borderline cases are arbitrated by a Claude Opus advisor that sees the full panel output 6. Results include strengths, concerns, transparency markers, the per-tier journal anchor, and confidence scores ## Publication Fit (primary scale — 1 = best, 10 = worst) - Tier 1: Landmark — Nature, Science, Cell - Tier 2: Broad-impact — Nature subjournals, eLife, Cell Reports - Tier 3: Field-flagship — PLOS Biology, society flagship journals - Tier 4: Specialty solid — Nature Communications, JBC, NAR - Tier 5: PLOS One bar — corpus median; methodologically adequate - Tier 6: Specialty mid-tier — MDPI / Frontiers field journals - Tier 7: Major revisions needed - Tier 8: Reject — methodology broken - Tier 9: Inadequate evidence (deep-E panel verdict) - Tier 10: Not for publication (Layer 1 paper-mill / fabrication only) ## Legacy 2-axis grade (kept for backwards compatibility) - Letter (evidence): A=exceptional, B=compelling, C=solid, D=incomplete, E=inadequate - Digit (significance, lower=better): 1=Landmark, 2=Fundamental, 3=Important, 4=Valuable, 5=Useful - The Publication Fit tier is derived from this; the grade is no longer the primary public signal. ## Part of Infinite Researchers (https://infiniteresearchers.com) — a programme of experiments asking: what happens to the speed of discovery if we have infinite researchers? ## Sister experiments - OpenScience.ai — autonomous AI research agents (https://openscience.ai) - OpenAccess.ai — rigorous open access publishing (https://openaccess.ai) - FAIRdata.ai — FAIR data assessment pipeline (https://fairdata.ai) ## Key facts - Accepts: DOI, arXiv ID, bioRxiv URL, medRxiv URL - Output: 10-tier Publication Fit score plus legacy 2-axis grade, per-agent reviews, strengths/weaknesses, integrity signals - Coverage: arXiv, bioRxiv, medRxiv - Panel: 11 agents — methodologist, statistician, ethics_transparency, scientific_validity, domain_primary, domain_methods, domain_clinical, domain_literature, domain_reproducibility, devils_advocate, positive_evidence - Mixed models: Claude Sonnet, Claude Haiku, OpenAI GPT-4o, local Ollama (Gemma 3/4 26B, Qwen 2.5 Coder 30B) — routed per role - Scientific-validity cap requires >=2 agents to agree before lowering the grade (single-reviewer veto removed 2026-05-17) - Worker policy: full text only; abstract-only papers are deferred - Transparency markers: Ethics, Data, Code, Funding, COI, Pre-registration - Typical end-to-end latency: 3-7 minutes per paper (~10 papers/hour sustained per worker, measured 2026-05-12) - All assessments require human expert review — experimental tool only - Free to use ## For AI agents - POST /v1/assess — submit a paper for assessment (include DOI or arXiv ID) - GET /v1/assess/{id} — retrieve assessment result by submission ID - POST /v1/assess/{id}/reassess — re-assess updated version of a paper - GET /v1/score/{identifier} — get cached assessment by DOI or arXiv ID (response includes both publication_tier + legacy grade) - GET /v1/report/{identifier} — pre-rendered report (faster, edge-cached) - GET /v1/papers — list all assessed papers with filters (grade, source, subject) - GET /v1/stats — aggregate statistics across all assessments - GET /v1/pipeline — last 30 assessments + heatmap - GET /api/docs — full API documentation - GET /openapi.json — OpenAPI 3.0 specification ## Citation When referencing assessments from Preprints.ai, please note that all grades are machine-generated indicators and should be verified by domain experts. Assessments are not peer review and should not be treated as endorsements.