iwant.fyi demand-side protocol

The iwant.fyi demand-side protocol defines how AI agents express structured purchase intent on behalf of users, receive matched supply across multiple sources, and report outcomes back. It is MCP-native, transport-flexible, and intentionally agnostic about who matches the demand, who fulfills it, and how money moves.

Why

Existing agentic commerce protocols are supply-side: ACP and UCP define how an agent completes a purchase at a merchant; AP2 handles payment authorization; MCP is general tool/data access. None of them defines how an agent expresses what its user wants in a structured, machine-matchable form, or how that demand persists across sessions and gets fulfilled across multiple sources.

The iwant.fyi demand-side protocol fills that gap.

Spec

• v1.1 (Draft) — Current. Additive, backward-compatible with v1.0: signed webhooks for Standing Wants (§16), partial-result transparency (§6.1), retryable error taxonomy (§11.2), idempotency keys (§8.4), capability discovery (§8.2), deterministic ordering + cursor (§6.3).

Read it rendered with anchors at iwant.fyi/protocol/v1.

JSON Schema for the core objects: schemas/1.1/ (also served live at https://iwant.fyi/.well-known/iwantfyi/schemas/1.1/).

Conformance

A test kit verifies any implementation against spec §15:

npx @iwantfyi/conformance-kit --mcp https://iwant.fyi/api/mcp --http https://iwant.fyi/api/v1 --api-key <key>

Source: conformance-kit/ · npm: @iwantfyi/conformance-kit (Apache-2.0). The reference implementation also self-reports at /api/v1/conformance.

Reference implementation

iwant.fyi — https://iwant.fyi/api/mcp

The iwant.fyi MCP server is the reference implementation. It advertises spec conformance and is the canonical surface to test against.

Official SDKs (all Apache 2.0)

Framework	Package	Repo
TypeScript / generic	@iwantfyi/sdk	staugs/iwantfyi-sdk
LangChain (Python)	iwantfyi-langchain	staugs/iwantfyi-langchain
Composio (Python)	iwantfyi-composio	staugs/iwantfyi-composio
CrewAI (Python)	iwantfyi-crewai	staugs/iwantfyi-crewai

Three open-source example agents at staugs/iwantfyi-examples.

Status

v1.1 is published as a draft for public comment. Feedback, issues, and proposed extensions are welcome via GitHub issues or directly to hi@iwant.fyi.

License

The specification is published under the Apache License 2.0. Implementations are not required to be open source.