CrossingKey MCP

com.crossingkeyintelligencePublished by crossingkeyintelligence.comOfficial publisherv3.0.1Updated Nov 1, 2026

Agent-native MCP for governed commerce, x402 payments, paid capabilities, and verifiable receipts.

VerifiedStreamable HTTPWeb executableFinanceDeveloper ToolsBusiness & Commerce

Overview

AI-generated overview

Remote MCP for a governed machine-commerce marketplace: free discovery and quoting, plus paid x402 audits and validation tools settled in USDC on Base.

What you can do
  • Discover the provider, marketplace policy, offers, capabilities and catalog, with filtered search and unfiltered paging
  • Check requirements, estimate cost, preview result shape and run an execution preflight that stops before payment
  • Request a payment quote with gross price, fee split and x402 payment requirements
  • Submit provider and creator applications, and read public provider and capability metadata
  • Run paid audits and utilities: x402 compatibility, MCP schema, OpenAPI quality, machine-commerce readiness, launch and purchase-path audits, artifact integrity manifests, hashing, secret and PII scanning, JSON repair, prompt scoring and XKEY validation
When to use it
Use it when an assistant needs to explore a paid capability marketplace, compare prices and requirements before committing, or run fixed-price audits of MCP endpoints, OpenAPI documents, x402 payment paths and text artifacts.
Requirements
A remote Streamable HTTP endpoint; no local package, account or API key is declared. Paid tools are priced in USDC on Base mainnet via x402, so a buyer-side payment path and human authorization are needed for those. Network access to the public endpoint.
Before you install
Thirteen tools are paid, from $0.01 to $19.00 USDC on Base; calling them returns a payment challenge rather than spending, but completing payment spends real funds. Provider and creator application tools are public write surfaces. Scans are heuristic and not comprehensive, and JSON repair may return supplied content. Do not send private keys, seed phrases or secrets; the seller wallet is receiver-only and agents get no signing authority.

Installation

In SourceWeft

  1. Open CrossingKey MCP in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/com.crossingkeyintelligence%2Fcrossingkey-mcp/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "crossingkey": {
      "type": "http",
      "url": "https://mcp.crossingkeyintelligence.com/mcp"
    }
  }
}

README

CrossingKey MCP

Agent-native MCP for governed commerce, x402 payments, paid capabilities, and verifiable receipts.

Production

Endpoint

https://mcp.crossingkeyintelligence.com/mcp

Canonical identity

com.crossingkeyintelligence/crossingkey-mcp

Stable source target

5.0.1 — the exact dependency-hardening source being prepared for promotion.

Current public runtime before host cutover

5.0.0 — the current public runtime before the v5.0.1 host cutover.

Promotion state

The source is being prepared as patch release 5.0.1. The host-side restart and GitHub release/tag are performed only after the running process is verified against this exact source.

Public verification

  • Cloudflare Tunnel crossingkey-mcp is healthy.
  • mcp.crossingkeyintelligence.com routes to the V5 origin on 127.0.0.1:3401.
  • Public discovery reports V5, Streamable HTTP, and Base mainnet eip155:8453.
  • No live payment or Base settlement is implied by discovery metadata alone.

This repository is the source of truth for the v5.0.1 candidate. Runtime deployment and release tagging are tracked separately.

Public documentation

Transport

MCP Streamable HTTP

CrossingKey MCP v5.0.1

CrossingKey MCP is a governed machine-commerce interface for AI agents and authorized software clients.

The stable source preserves the existing anonymous MCP surface and adds the two authorized v4 paid audits. The exact live/public tool count remains a deployment-time verification item.

  • 7 free discovery and commercial-navigation tools
  • 8 public marketplace tools
  • 13 direct x402 paid tools plus a separately named legacy credit-redemption compatibility tool for existing customers

Authenticated sessions additionally expose verification and role-gated marketplace operations.

The operating principle is:

Discovery is free. Evaluation is safe. Payment is explicit. Authority stays bounded. Execution is deterministic. Fulfillment is verifiable.

Free discovery

These seven tools can be used anonymously to understand the provider, available offers, requirements, price, expected result, authorization state, and prepaid-credit options without spending money:

  • provider.describe
  • offers.list
  • requirements.check
  • cost.estimate
  • result.preview
  • execution.preflight
  • credits.options (legacy compatibility status; new credit sales are disabled)

The normal discovery sequence is:

text
provider.describe→ offers.list→ requirements.check→ cost.estimate→ result.preview→ execution.preflight→ credits.options (legacy compatibility status; new credit sales are disabled)

A valid commercial flow may reach:

text
READY_FOR_HUMAN_AUTHORIZATION

and then stop at:

text
STOPPED_BEFORE_PAYMENT

until the required buyer authorization and payment conditions are satisfied.

Public marketplace discovery

The preserved anonymous marketplace surface also exposes:

  • marketplace.describe
  • provider.register
  • provider.get
  • capability.get
  • capability.search
  • catalog.list
  • commerce.quote
  • creator.apply

Discovery, catalog browsing, capability inspection, and quoting do not themselves authorize paid execution.

provider.register and creator.apply are public write surfaces for application and intake workflows. They do not grant unrestricted commercial authority.

Paid and gated execution

These 13 tools perform valuable computation, validation, or artifact generation and use direct x402 payment:

  • x402.compatibility_audit
  • mcp.schema_audit
  • openapi.quality_audit
  • machine_commerce.readiness_audit
  • artifact.integrity_manifest
  • xkey.validate

Current v4 paid capabilities use exact x402 Base USDC payments. Historical prepaid credit balances remain redeemable only through the separately named legacy compatibility path; v4 does not sell new credit packs.

Free discovery does not consume paid execution credits.

Authenticated verification

Authenticated sessions can expose read-only verification tools including:

  • approval.verify
  • idempotency.inspect
  • receipt.verify
  • entitlement.inspect

Marketplace sessions may additionally expose role-gated job, receipt, purchase, provider, capability, and settlement operations.

Approval minting remains a local operator action and is not exposed over MCP.

Commercial flow

The governed machine-commerce path is:

text
discover→ inspect requirements→ estimate cost→ preview result→ preflight→ authorize→ pay→ verify settlement→ execute→ issue result→ bind entitlement→ issue verifiable receipt

Payment alone does not create unrestricted authority.

Authorization, payment verification, execution, fulfillment, entitlement creation, and receipt generation remain separate governed stages.

Human authorization

CrossingKey does not treat an LLM-supplied boolean such as approved: true as buyer authorization.

Where human authorization is required, approval is bound to the relevant commercial context, including the buyer, capability, inputs, quote, idempotency state, and expiration conditions.

Paid execution does not occur merely because an agent asks for it.

MCP resources

The candidate preserves the public MCP resources for agent comprehension:

  • crossingkey://discovery-guide
  • crossingkey://commerce-policy
  • crossingkey://capability/{name}

These describe the free discovery sequence, commerce policy, and per-capability instructions.

Machine commerce

CrossingKey supports governed machine-payment infrastructure including:

  • x402 v1
  • x402 v2
  • Base USDC
  • historical prepaid request credits through a separately named compatibility path only
  • settlement verification
  • entitlements
  • result-bound receipts
  • idempotent execution
  • replay protection

The CrossingKey seller wallet boundary is receiver-only.

Agents are not granted unrestricted wallet signing, sending, swapping, bridging, or autonomous seller-spend authority.

Security properties

The production design includes:

  • bounded input validation
  • strict capability schemas
  • SSRF protections
  • DNS and address validation
  • response-size controls
  • authorization boundaries
  • approval binding
  • idempotency protection
  • payment replay protection
  • duplicate-settlement protection
  • deterministic result hashing
  • entitlement binding
  • receipt verification
  • receiver-only seller wallet policy
  • explicit uncertain-settlement handling

No private keys, wallet secrets, Stripe secrets, API keys, seed phrases, mnemonics, or private customer information belong in this repository.

Agent discovery

Recommended entry point:

provider.describe

Canonical MCP endpoint:

https://mcp.crossingkeyintelligence.com/mcp

Canonical identity:

com.crossingkeyintelligence/crossingkey-mcp

Official MCP Registry identity:

com.crossingkeyintelligence/crossingkey-mcp

Website:

https://www.crossingkeyintelligence.com

CrossingKey Intelligence

Operating online under the handle crossingkey_.

intelligence is the standard.

Source: README.md at commit f907add

Tools

28

marketplace.describe

FREE, read-only marketplace overview. Use this first for marketplace-specific capability commerce, fee policy, creator rights, payment rails, and active catalog counts; use provider.describe for the broader CrossingKey provider and legacy offer surface.

Takes no parameters.

provider.apply

FREE public application intake. Always pending, never creates credentials or active capabilities.

ParametersslugrequiredcontactrequiredwebsitedescriptionrequireddisplayNamerequired

provider.get

FREE. Public active provider metadata. Pending applications require owner or administrator authorization.

ParametersproviderIdrequired

capability.get

FREE. Use name for legacy deterministic capability metadata or capabilityId for public marketplace metadata, rights and provenance.

ParametersnamecapabilityId

catalog.list

FREE MARKETPLACE UNFILTERED DISCOVERY ONLY. Page through active public marketplace capabilities when no search filters are needed. Metadata is free; execution, entitlement, delivery, and purchased output remain gated. Do NOT use for filtered discovery; use capability.search. Do NOT use for CrossingKey digital/service offers; use offers.list. For one exact capabilityId use capability.get.

Parameterslimitoffset

commerce.quote

FREE MARKETPLACE PAYMENT QUOTE ONLY. After selecting an active marketplace capabilityId, return authoritative gross price, CrossingKey fee, provider share, and x402 v1/v2 payment requirements. A quote grants no entitlement and performs no execution. Do NOT use for first-party paid capabilities; use cost.estimate (first-party x402 capabilities have fixed catalog prices and no quote stage). Do NOT use for generic price lookup; use cost.estimate. Paid marketplace execution requires capability.purchase with authorization and verified payment.

ParameterscapabilityIdrequired

creator.apply

FREE WRITE. Private creator intake for assets needing a capability model. No ownership transfer and AI training defaults false.

Parameterssummaryrequiredproviderrequired

provider.describe

FREE read-only provider and commerce policy discovery. Use this before selecting an offer or capability.

Takes no parameters.

offers.list

FREE read-only public offer and capability discovery. This tool never starts payment or execution.

Parameterslimitqueryoffset

requirements.check

FREE read-only requirements check. This tool never authorizes or starts payment or execution.

Parametersitem_idrequired

cost.estimate

FREE read-only cost estimate. This tool never creates checkout, reserves funds, or contacts a facilitator.

Parametersitem_idrequired

result.preview

FREE read-only result-shape preview. This tool never executes a capability or creates an entitlement or receipt.

Parametersitem_idrequired

execution.preflight

FREE read-only execution preflight. Returns READY_FOR_HUMAN_AUTHORIZATION only; it never authorizes, purchases, settles, executes, or creates records.

Parametersitem_idrequired

credits.options

FREE read-only legacy credit compatibility status. New prepaid-credit sales are disabled in v4; historical paid credits remain redeemable through a separate compatibility path.

Takes no parameters.

x402.compatibility_audit

Purchase x402 Compatibility Audit

PAID $1.00 USDC on Base via x402. Audits an x402 endpoint for v1/v2 compatibility defects. Calling this MCP tool does not spend funds; it returns the exact PAYMENT-REQUIRED challenge and canonical paid execution endpoint.

Parametersurlrequired

mcp.schema_audit

Purchase MCP Schema Audit

PAID $1.00 USDC on Base via x402. Scores supplied MCP tool schemas for discoverability, descriptions, and bounded input contracts. Calling this MCP tool does not spend funds; it returns the exact PAYMENT-REQUIRED challenge and canonical paid execution endpoint.

Parameterstoolsrequired

openapi.quality_audit

Purchase OpenAPI Quality Audit

PAID $1.00 USDC on Base via x402. Evaluates structural quality and required fields in an OpenAPI document. Calling this MCP tool does not spend funds; it returns the exact PAYMENT-REQUIRED challenge and canonical paid execution endpoint.

Parametersspecrequired

machine_commerce.readiness_audit

Purchase Machine-Commerce Readiness Audit

PAID $2.00 USDC on Base via x402. Checks machine-commerce discovery and health surfaces. Calling this MCP tool does not spend funds; it returns the exact PAYMENT-REQUIRED challenge and canonical paid execution endpoint.

Parametersurlrequired

artifact.integrity_manifest

Purchase Artifact Integrity Manifest

PAID $0.10 USDC on Base via x402. Creates deterministic SHA-256 entries and a root manifest hash for supplied text artifacts. Calling this MCP tool does not spend funds; it returns the exact PAYMENT-REQUIRED challenge and canonical paid execution endpoint.

Parametersartifactsrequired

hash.encode

Purchase SHA-256 Text Hash

PAID $0.01 USDC on Base via x402. Computes a SHA-256 digest and UTF-8 byte count for supplied text. Calling this MCP tool returns a payment challenge and does not autonomously spend funds.

Parameterstextrequired

secret.scan

Purchase Secret Pattern Scan

PAID $0.01 USDC on Base via x402. Detects selected credential patterns and returns classifications and positions, not matched values. Heuristic, not comprehensive. Calling this MCP tool returns a payment challenge and does not autonomously spend funds.

Parameterstextrequired

pii.scan

Purchase PII Pattern Scan

PAID $0.01 USDC on Base via x402. Detects selected personal-data patterns and returns classifications and positions, not matched values. Heuristic, not comprehensive. Calling this MCP tool returns a payment challenge and does not autonomously spend funds.

Parameterstextrequired

json.repair

Purchase Conservative JSON Repair

PAID $0.01 USDC on Base via x402. Validates JSON and repairs a limited set of formatting errors. May return supplied content. Calling this MCP tool returns a payment challenge and does not autonomously spend funds.

Parameterstextrequired

prompt.audit

Purchase Prompt Heuristic Audit

PAID $0.01 USDC on Base via x402. Scores selected prompt structure signals using deterministic heuristics. Calling this MCP tool returns a payment challenge and does not autonomously spend funds.

Parameterstextrequired

mcp.launch_audit

MCP Launch Audit

PAID $9.00 USDC on Base via x402. Performs bounded live MCP discovery, health, transport, schema, and receiver-only checks against a public endpoint. No payment is attempted by the audit.

Parametersurlrequired

x402.purchase_path_audit

x402 Purchase-Path Audit

PAID $19.00 USDC on Base via x402. Performs a bounded no-payment purchase-challenge audit for a selected capability, validating status, requirements, destination, amount, and receiver-only controls.

Parametersurlrequiredcapabilityrequired

xkey.validate

XKEY Intake Validation

PAID $0.10 USDC on Base via x402. Validates and normalizes one bounded XKEY intake payload. Calling this MCP tool returns the exact PAYMENT-REQUIRED challenge and does not spend funds.

Parametersraw_intakerequiredidempotency_keyrequired

Version history

3
  1. v3.0.1LatestOct 11, 2026
  2. v3.0.0Sep 29, 2026
  3. v2.3.0Sep 16, 2026

Score

90% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listedRequired15 pts
  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts

    Declare a license in the repository or the registry entry.