MCP Argument Drift
See which tool arguments changed obligation between two MCP manifests. Separates tightening, where every existing call now fails, from loosening, where a tool may be invoked without something it previously demanded. A newly required argument is the single change most likely to break an agent that was working yesterday.
Otherofflineeip155:8453Exactvia cdp
McpAgent toolingRequired argumentsRelease safetyDeveloper tooling
Settlements · 30d
218↓ 56%
No per-endpoint history for this service yet, so this is payments indexed to its PROVIDER's wallet over 30 days.
$25.35
Verified settled volume
256 settlements proven x402 by their on-chain EIP-3009 marker.
$0.100
Listed price
As published in the catalog. Always read the live 402 before paying.
1
Calls · 30d
Upstream's own call count for this endpoint, not ours.
1
Unique payers · 30d
Last called 2026-10-04 07:56Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0x25e8245f07d5e4873987293dad666afbe56a9608The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
Provider
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
0.1USDC≈ $0.1 USD
on Base · exact scheme
Pay 0.1 USDC on Base to 0x25e8…a9608. The signed payment is good for 1 minute.
- Paid to
- 0x25e8…a9608
- USD Coin contract
- 0x8335…02913
- Payment window
- 1 minute
- As published
- 100000 smallest units
The catalog’s raw entry
[
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x25e8245f07d5e4873987293dad666afbe56a9608",
"amount": "100000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 60
}
]Extensions
{
"bazaar": {
"info": {
"input": {
"body": {
"after": {
"tools": [
{
"name": "list_orders",
"annotations": {
"idempotentHint": true
},
"description": "List orders.",
"inputSchema": {
"type": "object",
"required": [
"tenant_id",
"region"
],
"properties": {
"page": {
"type": "integer",
"minimum": 1,
"description": "Page number, starting at 1."
},
"region": {
"type": "string",
"description": "Data region to query."
},
"status": {
"enum": [
"open",
"shipped",
"disputed"
],
"type": "string",
"description": "Restrict to one status."
},
"tenant_id": {
"type": "string",
"description": "The tenant whose orders to list."
}
}
},
"outputSchema": {
"type": "object",
"required": [
"items"
],
"properties": {
"items": {
"type": "array"
}
}
}
},
{
"name": "get_order",
"annotations": {
"readOnlyHint": true
},
"description": "Fetch one order by its identifier, including line items and the current fulfilment state.",
"inputSchema": {
"type": "object",
"required": [
"order_id"
],
"properties": {
"order_id": {
"type": "string",
"description": "The order identifier."
}
}
}
},
{
"name": "cancel_order",
"annotations": {
"idempotentHint": false,
"destructiveHint": true
},
"description": "Cancel an order that has not yet shipped. This cannot be undone and will issue a refund where one is due.",
"inputSchema": {
"type": "object",
"required": [
"order_id"
],
"properties": {
"reason": {
"type": "string",
"description": "Why it is being cancelled."
},
"order_id": {
"type": "string",
"description": "The order to cancel."
}
}
}
}
],
"serverInfo": {
"name": "orders-mcp",
"version": "2.0.0"
},
"capabilities": {
"tools": {
"listChanged": false
}
}
},
"before": {
"tools": [
{
"name": "list_orders",
"annotations": {
"readOnlyHint": true,
"idempotentHint": true
},
"description": "List orders for a tenant, newest first, with optional paging. Returns only orders the caller is entitled to see.",
"inputSchema": {
"type": "object",
"required": [
"tenant_id"
],
"properties": {
"page": {
"type": "integer",
"minimum": 1,
"description": "Page number, starting at 1."
},
"status": {
"enum": [
"open",
"shipped"
],
"type": "string",
"description": "Restrict to one status."
},
"tenant_id": {
"type": "string",
"description": "The tenant whose orders to list."
}
}
},
"outputSchema": {
"type": "object",
"required": [
"items"
],
"properties": {
"items": {
"type": "array"
},
"next_page": {
"type": [
"integer",
"null"
]
}
}
}
},
{
"name": "get_order",
"annotations": {
"readOnlyHint": true
},
"description": "Fetch one order by its identifier, including line items and the current fulfilment state.",
"inputSchema": {
"type": "object",
"required": [
"order_id"
],
"properties": {
"order_id": {
"type": "string",
"description": "The order identifier."
}
}
},
"outputSchema": {
"type": "object",
"required": [
"id"
],
"properties": {
"id": {
"type": "string"
},
"total": {
"type": "number"
}
}
}
},
{
"name": "cancel_order",
"annotations": {
"idempotentHint": false,
"destructiveHint": true
},
"description": "Cancel an order that has not yet shipped. This cannot be undone and will issue a refund where one is due.",
"inputSchema": {
"type": "object",
"required": [
"order_id"
],
"properties": {
"reason": {
"type": "string",
"description": "Why it is being cancelled."
},
"order_id": {
"type": "string",
"description": "The order to cancel."
}
}
}
}
],
"serverInfo": {
"name": "orders-mcp",
"version": "1.3.0"
},
"capabilities": {
"tools": {
"listChanged": true
},
"resources": {
"subscribe": true
}
}
}
},
"type": "http",
"method": "POST",
"bodyType": "json"
},
"output": {
"type": "json",
"example": {
"limits": {
"maxCalls": 1000,
"maxTools": 400,
"maxServers": 20,
"maxFindings": 500,
"confusableOverlap": 0.6
},
"stable": false,
"complete": true,
"findings": [
{
"code": "REQUIRED_ARGUMENT_ADDED",
"tool": "list_orders",
"detail": "list_orders: region is new and required, so every existing call fails.",
"argument": "region"
}
],
"request_id": "example-request",
"service_id": "mcp_required_argument_drift",
"assumptions": [
"Tightening breaks every existing call; loosening means a tool may now be invoked without something it previously demanded.",
"Tools present in only one manifest are left to mcp_toolset_diff rather than reported twice."
],
"limitations": [
"Argument obligation only. Value-level schema compatibility is mcp_breaking_change_report.",
"stable is true only when both manifests were read in full and no obligation moved in either direction."
],
"observed_at": "2026-10-02T00:00:00.000Z",
"not_examined": [],
"finding_count": 1,
"loosened_count": 0,
"tools_compared": 3,
"service_version": "1.0.0",
"tightened_count": 1,
"findings_by_code": {
"REQUIRED_ARGUMENT_ADDED": 1
}
}
}
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"input"
],
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method",
"bodyType",
"body"
],
"properties": {
"body": {
"type": "object",
"required": [
"before",
"after"
],
"properties": {
"after": {},
"before": {}
},
"additionalProperties": false
},
"type": {
"type": "string",
"const": "http"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"type": "string"
},
"example": {
"type": "object"
}
}
}
}
}
}
}Provenance
- Seen in the source catalog
- 2026-10-04 07:56Z
- Last indexed by Roundhouse
- 2026-10-05 00:20Z
- Last enriched (probe, favicon, geo)
- 2026-10-04 10:45Z
- x402 version
- 2
- Max timeout
- 60s
- Liveness probe
- HTTP 0
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
No per-endpoint history for this service yet, so this is payments indexed to its PROVIDER's wallet over 30 days. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service MCP Argument Drift and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=MCP%20Argument%20Drift' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://api.zfinia.com/x402/v1/mcp-required-argument-drift, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Either pay over x402 (mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402), or ask me for an organization key, which I create at https://roundhouseai.io/dashboard/connections. If you have neither, ask before going further. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.