util_x402_payment_replay_key

SERVERDelx Mcp A2a SOURCEhttps://api.delx.ai/v1/mcp

Low RISK CLASS

Category Read

Parameters 33 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-davidmosiah-delx-mcp-a2a/util-x402-payment-replay-key.md

WHAT IT DOES

What util_x402_payment_replay_key does on Delx Mcp A2a

AI agents call util_x402_payment_replay_key to retrieve information from Delx Mcp A2a without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

Parameter	Type	Required	Description
`nonce`	string	Yes	Nonce supplied to X402 Payment Replay Key; used only for this bounded calculation and processed in memory without retention.
`payer`	string	Yes	Payer supplied to X402 Payment Replay Key; used only for this bounded calculation and processed in memory without retention.
`resource`	string	Yes	Resource supplied to X402 Payment Replay Key; used only for this bounded calculation and processed in memory without retention.

Parameters from the server's own tool schema.

RISK

Why util_x402_payment_replay_key is rated Low

Even though util_x402_payment_replay_key only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs util_x402_payment_replay_key safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Delx Mcp A2a, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For util_x402_payment_replay_key, this is the rule to start with:

util_x402_payment_replay_key Allowed

util_x402_payment_replay_key is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "util_x402_payment_replay_key": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Delx Mcp A2a, apply this rule, and every util_x402_payment_replay_key call is checked against it from then on.

FAQ

Questions about util_x402_payment_replay_key

What does the util_x402_payment_replay_key tool do? +

X402 Payment Replay Key derives a stable non-secret replay-detection key from payment metadata from bounded caller-supplied values without an external provider. Call X402 Payment Replay Key before paying for or accepting an x402 or agent delivery assembled from caller-supplied challenge and result metadata. Returns contract-specific checks, normalized evidence, mismatch reasons, and an explicit acceptance or rejection status for X402 Payment Replay Key as versioned deterministic JSON. Limitation: Validates metadata only; it never settles payment, signs payloads, contacts a facilitator, refunds funds, or asserts on-chain truth. It is categorised as a Read tool in the Delx Mcp A2a MCP Server, which means it retrieves data without modifying state.

What parameters does util_x402_payment_replay_key accept? +

util_x402_payment_replay_key accepts 3 parameters: nonce, payer, resource. Required: nonce, payer, resource. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on util_x402_payment_replay_key? +

Register the Delx Mcp A2a MCP server in PolicyLayer and add a rule for util_x402_payment_replay_key: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Delx Mcp A2a. Nothing to install.

What risk level is util_x402_payment_replay_key? +

util_x402_payment_replay_key is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit util_x402_payment_replay_key? +

Yes. Add a rate_limit block to the util_x402_payment_replay_key rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block util_x402_payment_replay_key completely? +

Set action: deny in the PolicyLayer policy for util_x402_payment_replay_key. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides util_x402_payment_replay_key? +

util_x402_payment_replay_key is provided by the Delx Mcp A2a MCP server (https://api.delx.ai/v1/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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