# Implementation Options Research

## Summary

This document captures the MVP stack decisions for ResearchLink AI based on an analysis of available tools, libraries, and patterns as of 2026.

---

## PDF Parsing Options

| Tool | Pros | Cons | Decision |
|------|------|------|----------|
| **PyMuPDF (fitz)** | Fast, reliable text + structure extraction, layout-aware | C extension, requires libmupdf | **Selected** |
| pypdf | Pure Python, lightweight | Poor structure extraction, no layout | Backup only |
| pdfplumber | Good table extraction | Slow on large PDFs | Future use for tables |
| Marker | ML-based, high quality | Heavy dependencies, GPU preferred | Stage 2 |
| Grobid | Best scientific structure parsing | Java service, complex setup | Future self-hosted option |

**Recommendation:** PyMuPDF for MVP. Grobid for Stage 2 if high-quality extraction is needed.

---

## Metadata Lookup Options

| Service | API | Free Tier | Notes |
|---------|-----|-----------|-------|
| **Semantic Scholar** | REST, no key required | Yes (rate limited) | **Selected** |
| OpenAlex | REST, no key required | Yes | Good coverage, fast |
| Crossref | REST, polite pool | Yes | Best for DOIs |
| arXiv API | Atom/REST | Yes | Best for arXiv papers |
| SSRN | No public API | N/A | Manual only |
| OpenReview | REST | Yes | Good for NeurIPS/ICLR |

**Recommendation:** Semantic Scholar as primary, Crossref for DOI enrichment. Both are free and well-documented.

---

## Citation Validation Options

| Approach | Quality | Complexity |
|----------|---------|------------|
| Regex + heuristics | Low-medium | Low | 
| **bibtexparser + heuristics** | Medium | Low | **Selected for MVP** |
| Crossref/Semantic Scholar lookup | High | Medium |
| anystyle-parser | High (Ruby) | High |

**Recommendation:** bibtexparser for BibTeX parsing + Crossref for DOI verification in Stage 2.

---

## GitHub Repository Analysis Options

| Approach | Coverage | Auth Required |
|----------|----------|---------------|
| **GitHub REST API (unauthenticated)** | Public repos | No (rate-limited) | **Selected** |
| GitHub REST API (token) | Public + higher rate limit | Yes | Recommended for production |
| GitHub GraphQL API | Rich queries | Yes |
| GitPython (local clone) | Full access | No (local) |

**Recommendation:** GitHub REST API unauthenticated for MVP. Support `GITHUB_TOKEN` env var for higher rate limits.

---

## Multi-Agent Orchestration Options

| Framework | Description | Decision |
|-----------|-------------|----------|
| **Custom sequential pipeline** | Simple, transparent, no overhead | **Selected for MVP** |
| LangChain Agents | Many integrations, complex | Overkill for MVP |
| LlamaIndex | Good for RAG, less for pipeline | Stage 2 option |
| CrewAI | Role-based agents | Stage 2 option |
| AutoGen | Conversational multi-agent | Research tool option |

**Recommendation:** Custom sequential pipeline for MVP. Migrate to CrewAI or custom async orchestration in Stage 2.

---

## Markdown and Documentation Generation Options

| Tool | Use Case | Decision |
|------|----------|----------|
| **Jinja2** | Template rendering | **Selected** |
| **Direct LLM generation** | Content writing | **Selected** |
| MkDocs | Documentation site | Stage 2 |
| Pandoc | Format conversion | Future |

**Recommendation:** Jinja2 for structure templates. Direct LLM (Claude) calls for content generation.

---

## Recommended MVP Stack

```
Python 3.11+
typer — CLI
pydantic v2 — schemas and validation
PyYAML — YAML I/O
jinja2 — templates
httpx — HTTP client
pymupdf — PDF text extraction
anthropic SDK — LLM calls (claude-sonnet-4-6)
bibtexparser — BibTeX parsing
rich — CLI output
python-slugify — slug generation
pytest — tests
ruff — linting
```

---

## Future SaaS Stack

```
FastAPI — REST API backend
Next.js — web frontend
PostgreSQL — persistent storage
Redis — caching and task queue
Celery — background workers
MinIO / S3 — PDF and asset storage
GitHub App — OAuth + webhook integration
Docker + Kubernetes — deployment
Stripe — billing
```

---

## Risks and Tradeoffs

| Risk | Impact | Mitigation |
|------|--------|------------|
| PDF extraction quality varies | Medium | Mark confidence; allow manual override |
| LLM generates hallucinated citations | High | Never auto-trust LLM citations; mark all as needs-verification |
| Semantic Scholar rate limits | Low | Add exponential backoff; cache responses |
| GitHub API rate limits (unauthenticated) | Medium | Support GITHUB_TOKEN; cache tree responses |
| Paper text may be behind paywall | Medium | Document clearly; accept user-provided PDFs |
| LLM API cost at scale | High | Batch requests; cache outputs; Stage 2 cost controls |