Developer docs · MCP

Connect Claude
or Cursor to Ysaere.

Remote Streamable HTTP MCP for classify, KYB, briefs, Notary, and full research swarms (Angel / CI / Market / DD / Security). Without a key you get a taste session: free company_snapshot and estimate_credits, plus accountless x402 on sync tools (classify_entities, kyb_verify, quick_brief, sourced_brief, vault_search, notary_hash) — send Accept-Payment: x402 (USDC) or settle the challenge; no Ysaere signup required for those. Prepaid credits (OAuth or ysa_prod_*) work on the same sync tools and are required for swarm tools.

Create a free account Open setup wizard (signed in)
Streamable HTTP Dual-rail: credits · x402 OAuth 2.1 + PKCE API key fallback Traceable outputs
Endpoint

Server URL

Use this URL in Claude Connectors, Cursor MCP config, or MCP Inspector:

MCP URL
https://mcp.ysaere.com/mcp
Transport
streamable-http
Health
https://mcp.ysaere.com/health
Browser: status page · automated probes: JSON ok
Authentication

OAuth (Claude Directory and custom connectors)

Preferred for Claude. User consent via Ysaere sign-in. No Dynamic Client Registration.

Client ID
claude.ai
Client secret
(none: public PKCE client)
Authorization server
https://api.ysaere.com

API key (Cursor / Inspector)

Create an MCP-enabled production key in the app (Developer → MCP Server), then send Authorization: Bearer ysa_prod_…. Sandbox keys are rejected for MCP. This is the credits rail.

Accountless x402 (machines / agents)

Sync tools accept Accept-Payment: x402 with no Bearer. MCP returns payment_required with needs_account: false and _meta["x402/payment"] (same challenge as REST HTTP 402). Settle USDC via the facilitator, retry with Payment-Signature / X-PAYMENT. Dual-rail sync tools: classify_entities ($0.20), kyb_verify ($0.50), quick_brief, sourced_brief, vault_search, notary_hash. Swarm tools (Angel, CI, DD, …) still need an account.

Quick start

Three steps

  1. Connect to https://mcp.ysaere.com/mcp (no key for taste + x402 sync tools; OAuth or ysa_prod_* for credits / swarms).
  2. Taste: company_snapshot (free) or pay classify_entities / kyb_verify accountlessly via x402.
  3. Optional account: sign up at app.ysaere.com for prepaid credits, then Angel / CI → wait_for_report → verify_provenance.

Webhooks (REST companion)

MCP tools poll with wait_for_report. For backends that prefer push, register POST /v1/webhooks with event report.completed (HMAC-signed; SSRF-validated URL). See Builders → Examples.

Example prompts

Try these in Claude

Use company_snapshot on Stripe.

Hash this sentence with SHA-512, then call notary_hash in hash_only mode. Tell me what the receipt proves (integrity, not that the sentence is true).

Classify these: Stripe, Patrick Collison, React

Run kyb_verify on Acme Corp before I onboard them.

Check my Ysaere credit balance, then check status of my latest report.

Capabilities

What you can do

Free taste, dual-rail sync SKUs (credits or accountless x402), then account-gated research swarms. Provenance receipts attest integrity — not that every fact is verified truth.

Taste — Snapshot · Estimate · Balance hintcompany_snapshot · estimate_credits · check_balanceFree / keyless
Dual-rail sync (credits or accountless x402)classify_entities · kyb_verify · quick_brief · sourced_brief · vault_search · notary_hash2–40 cr / USDC
Status · Wait · Verify provenancecheck_report_status · wait_for_report · verify_provenanceAccount
Company Intelligencecompany_intelligence · competitive_intelligence100 cr · account
Market Intelligencemarket_intelligence150 cr
Angel Intelligence · Angel Deepangel_intelligence · angel_deep_intelligence50 / 90 cr
Due Diligencedue_diligence200 cr
Security Assessmentsecurity_assessment75 cr

Tool names above are what Claude / Cursor call. HTTP API: api.ysaere.com/v1/openapi.json · Examples: ysaere.com/builders/examples/

Requirements and legal

Rails, credits, disclosure

Signed-in users: copy Cursor JSON and manage keys at app.ysaere.com/developer/mcp.

Ready to connect.

Connect Claude or Cursor, taste with free company_snapshot, pay classify/KYB via x402 or credits, then use an account for Angel or Company Intelligence.

Start free Setup wizard