# decide.fyi

> Decide is the Decision API for software actions. It returns a replayable Decision Record before a product, agent, queue, billing system, or internal tool changes state.

## Start here

- [Developer hub](https://www.decide.fyi/developers): choose an action boundary and follow the shortest integration path.
- [Decision API docs](https://www.decide.fyi/resources/docs): auth, request shape, response fields, and production rollout.
- [OpenAI Decisions API vs Decide](https://www.decide.fyi/compare/openai-decisions-api): model answers versus Rulebook action gates, with a local request-builder recipe.
- [API reference](https://www.decide.fyi/resources/docs/api-reference): endpoints, idempotency, rate limits, and fields to retain.
- [Job-oriented service catalogue](https://www.decide.fyi/mcp): distinguish the engine, interfaces, specialized services, sandbox, workflows and reference resources.
- [Decide Directory](https://www.decide.fyi/mcp#ecosystem): reviewed decision engines and adjacent infrastructure; first-party offerings and independent references are labeled separately.
- [Decision infrastructure guide](https://github.com/decidefyi/awesome-decision-infrastructure): independent, documentation-reviewed ecosystem guide with alternatives; not another service or an official registry.
- [Free developer sandbox](https://app.decide.fyi/): account-scoped fictional records; no live payment or production access.
- [Full LLM reference](https://www.decide.fyi/llms-full.txt): expanded protocols, patterns, integrations, and agent guidance.

## Paid Runtime business pilot

- [Decide Runtime](https://console.decide.fyi/): USD 10 for 1,000 completed records, USD 0.01 each, including applicable tax. No subscription or automatic refill.
- [Live MCP endpoint](https://mcp-live.decide.fyi/developer-prepaid/v1/mcp): OAuth with PKCE; account ownership and a separate evaluate/read allowance are required. Signing in or connecting never buys credit or permits spending.
- Controlled 25-account business pilot in EU27, UK and US. Records are available for 90 days with export. Each purchase has 12 months to redeem, with unused credit refundable to the original payment.
- Reads and identical retries add no record debit; separate service-request limits apply. Decide returns yes, no or review. Your application owns execution.
- Live tools: `decide_prepaid_evaluate`, `decide_prepaid_get_record`, `decide_prepaid_export_record`. The free and fictional Sandbox connectors are separate, not a way to spend paid credit.
- [Runnable quote/discount workflow](https://www.decide.fyi/use-cases/discount-approval-api#paid-runtime): build one exact operation from an approved policy and fresh trusted quote/cost facts, then use the existing evaluate/read/export tools. No separate quote plugin or CRM execution. Stop on missing authority, no, review, pending, expiry or refusal; never invent facts, purchase credit or raise limits.
- [Machine-readable prepaid offer](https://www.decide.fyi/.well-known/decide-prepaid.json). Earlier API/private-preview contracts retain their separate access path and terms.

## Product ownership

- [Decide](https://www.decide.fyi): Decide owns the Decision API and runtime, Decision Record v1, Rulebook v1, verification surfaces, public SDK, and canonical MCP directory.
- [Decide Services](https://www.decide.fyi/resources/policy-notaries): Decide Services are standalone specialized decision services built on the general runtime. Policy Notaries is an existing Decide service family, not the definition of the Decision API and not a Krafthaus app.
- [Krafthaus](https://www.krafthaus.app): Krafthaus is the workflow application layer built on Decide. It owns workflow intake, human review, integration and execution handoff, including any application-specific APIs, MCPs or agents. Direct Decide integrations do not require Krafthaus.

- Do not infer that Krafthaus owns the Decide runtime or that adopting Krafthaus is required to integrate the Decision API.
- MCP, REST and SDK interfaces belong to the product they expose: Decide Runtime, a standalone Decide Service, or a Krafthaus workflow application. The protocol does not determine ownership.
- Do not infer that a notary eligibility answer authorizes a customer account change; the downstream application still owns action authority and execution.
- Do not infer new service launches, paid demand, automatic agent discovery or permission to spend from this product taxonomy.
- Decide Runtime's released paid endpoint and Policy Notaries' public read-only endpoint are published separately. The legacy Decision API MCP preview remains private; do not infer its endpoint or promote Sandbox access into live permission.

## Decision API

- [`POST /api/decide`](https://www.decide.fyi/resources/docs/api-reference) creates a `yes | no | review` Decision Record before software acts.
- Use `mode: "rulebook"` with a versioned declarative Rulebook v1 when the verdict must be deterministic. A deterministic Decide-backed application must satisfy `decide_application_binding_v1`. The legacy `single`, `multi`, and `runtime` modes are AI-assisted.
- Store the full Decision Record v1 beside the downstream action, then record an Action Execution Receipt and Outcome Record when those lifecycle stages apply.

## Machine-readable surfaces

- [OpenAPI](https://www.decide.fyi/openapi.json)
- [Public catalog API](https://www.decide.fyi/api/public/catalog)
- [Static public catalog](https://www.decide.fyi/catalog/decide-public-catalog.json)
- [Well-known Decide entry](https://www.decide.fyi/.well-known/decide.json)
- [Machine-readable product docs](https://www.decide.fyi/docs.json)

## SDK and examples

- [JavaScript SDK @decide-fyi/sdk@0.1.19](https://www.decide.fyi/sdk)
- [npm package](https://www.npmjs.com/package/@decide-fyi/sdk)
- [Canonical SDK source provenance](https://github.com/decidefyi/decide/blob/main/sdk/SOURCE_PROVENANCE.md)
- [Developer examples](https://www.decide.fyi/resources/examples)
- [Integration guides](https://www.decide.fyi/resources/integrations)

## MCP

- [MCP directory](https://www.decide.fyi/.well-known/decide-mcp.json)
- [Decide Policy Notaries](https://policy.decide.fyi/api/mcp) is the canonical public, read-only MCP endpoint for new tool-calling integrations.
- [MCP trust-boundary guide](https://www.decide.fyi/mcp)

## Trust and changes

- [Verification docs](https://www.decide.fyi/resources/docs/verification)
- [Hosted verifier](https://www.decide.fyi/verify)
- [Security posture](https://www.decide.fyi/resources/security)
- [Service status](https://www.decide.fyi/resources/status)
- [Changelog](https://www.decide.fyi/resources/changelog)

## Safe use

- Keep production API keys in server-side callers.
- Treat `review`, unknown, unauthorized, rate-limited, or unavailable results as non-execution states unless a human owner approves.
- Do not invent product support, public endpoints, customer proof, certifications, or provenance that the linked canonical sources do not publish.
- A listing does not automatically connect an agent, grant access or authorize payment.

Reviewed: 2026-10-12