# STEM
> Multi-domain computation service. Ask questions spanning chemistry (molecular properties, structure rendering), physics (constants, unit conversion), and math (symbolic integration, differentiation, equation solving, matrix operations, limits, series).

Multi-domain STEM computation behind x402 micropayments. A single POST /stem/ask endpoint takes a natural-language question spanning chemistry, physics, and math. DeepSeek routes it to deterministic tools from a strict toolkit (RDKit for molecular properties/rendering, SymPy for symbolic math, Pint for dimensional analysis, scipy, CODATA physical constants) and returns a computed, verifiable answer with the list of tools used. The full deterministic tool set (JSON schemas) is exposed free at GET /stem/tools; a free /stem/diag reports service health.

## Pricing
- `exclusive` tier — **$0.256125** on Base: `/stem/ask`
- Chains: Base, Arbitrum, Polygon, Avalanche, Ethereum, Robinhood, Arc. Per-chain prices in `/.well-known/x402.json`.

## Operations
### inference
- **POST /stem/ask** — Ask a multi-domain STEM question combining chemistry, physics, and math computation. Returns a computed answer with the deterministic tools used. — params: `question` (string)* (tier: `exclusive`)

## Workflows
- **stem_ask** (Multi-domain STEM computation question): `stem_ask` — LLM routes to deterministic RDKit/SymPy/Pint tools.

## Data sources
- RDKit (chemistry) — Molecular properties + structure rendering.
- SymPy (math) — Symbolic integration, differentiation, solving, matrices, limits, series.
- Pint (units) — Dimensional unit conversion.
- scipy (math)
- CODATA physical constants (physics)

## Free endpoints
- GET `/`, `/health`, `/about`, `/.well-known/x402.json`, `/llms.txt`, `/openapi.json` (standard)
- GET `/stem/tools` — List all deterministic computation tools with JSON schemas
- GET `/stem/diag` — Service diagnostic / tool health check
- GET `/stem/feedback` — Return the 50 most recent feedback entries
- POST `/stem/feedback` — Submit feedback (response_id, rating 1-5, optional comment)

## Examples
- `stem_ask` — Multi-domain STEM question: `{"question": "What is the molecular weight of aspirin and its integral?"}`