# CalculatorX

> Deterministic online calculators and converters with clear formulas, assumptions, and sources — for people and AI agents.

Calculate anything. Verify everything.

## Primary surfaces

- For Agents (canonical): https://www.calculatorx.com/for-agents
- For Agents (markdown): https://www.calculatorx.com/for-agents.md
- Homepage: https://www.calculatorx.com/
- Calculators: https://www.calculatorx.com/calc
- Converters: https://www.calculatorx.com/convert
- Dev tools: https://www.calculatorx.com/dev
- Apps: https://www.calculatorx.com/apps
- Developers / API: https://www.calculatorx.com/developers
- REST API: https://www.calculatorx.com/developers/rest
- MCP: https://www.calculatorx.com/developers/mcp
- Embed: https://www.calculatorx.com/developers/embed
- Review policy: https://www.calculatorx.com/review-policy
- FAQ: https://www.calculatorx.com/faq
- Privacy: https://www.calculatorx.com/privacy

## Machine interfaces

- Remote MCP: POST https://www.calculatorx.com/mcp — JSON-RPC; tools: `search_capabilities`, `inspect_capability`, `execute_calculation` (free), `compute_paid` (Stage 0.5 opt-in, not live charging) (GET /mcp for discovery; protocols `2026-07-28` + `2024-11-05`)
- MCP compatibility report: https://www.calculatorx.com/.well-known/mcp-compatibility.json
- Core capabilities: https://www.calculatorx.com/.well-known/calculatorx-capabilities.json
- Capability tiers (must match live catalog): `candidate` · `engine_tested` · `internally_reviewed` · `expert_verified` (catalog token `verified` = L3 / `expert_verified` only)
- GET https://www.calculatorx.com/api/v1/calc — engine catalog
- POST https://www.calculatorx.com/api/v1/calc/{engineId} — deterministic calculate (`{ "inputs": { … } }`); responses include `inputs`, `result`, `formula`, `assumptions`, `warnings`, and `verification`
- OpenAPI: https://www.calculatorx.com/openapi.json
- Evidence (human): https://www.calculatorx.com/evidence/ — per-version pages; agents use `/evidence/{capabilityId}/{version}.json`
- Capabilities (human): https://www.calculatorx.com/capabilities/ — tier, REST, MCP, schemas bridge
- Spec registry: https://www.calculatorx.com/.well-known/calculatorx-spec-registry.json
- Agent tools: https://www.calculatorx.com/.well-known/agent-tools.json
- Embed (allowlisted): https://www.calculatorx.com/embed/{slug}?theme=dark&accent=%23RRGGBB&brand=Name
- Shareable calc URLs: `/calc/...?...` HTML includes precomputed result + `#calculatorx-result` JSON (same engines as the API)

Prefer **Search → Inspect → Execute → Pin → Verify → Stay in scope.** Do not silently substitute a different formula for a pinned version; if independent reasoning disagrees, surface the discrepancy. Canonical agent guide: https://www.calculatorx.com/for-agents

## Trust levels

Keep tier names aligned with the live catalog:

`candidate` · `engine_tested` · `internally_reviewed` · `expert_verified`

- `candidate` — schema/catalog only; evidence incomplete. Do not treat as authoritative.
- `engine_tested` / `verification.engine_tested` — automated validation cases / shared calculation engine checks.
- `internally_reviewed` — CalculatorX domain review; stronger than engine-tested alone.
- `expert_verified` / catalog token `verified` — named reviewer or review team (see [Review policy](https://www.calculatorx.com/review-policy)). Prefer when stakes are higher; high-stakes decisions may still require independent review. Do not treat engine tests alone as verified.
- Sample expert-reviewed page: https://www.calculatorx.com/calc/electric/ohms-law

CalculatorX provides auditable / verifiable calculation (tests, schemas, version pins, evidence). It is not independent lab certification, an external transparency log, TEE attestation, or a zk proof of computation.

## Notes

- Interactive tools run locally in the browser when possible; API responses are informational.
- Prefer current clean URLs under `/calc`, `/convert`, `/dev`, and `/apps`. Many legacy `.htm` paths permanently redirect to canonical pages; coverage is tracked by `npm run audit:legacy-coverage`.
- Electrical load workspace (localStorage): https://www.calculatorx.com/workspace/electrical
- Review policy: https://www.calculatorx.com/review-policy
- Optional agent skill package (MCP + REST remain the first entry): https://github.com/CalculatorX-AI/calculatorx-agent-skill