FOXIFY Agent Payment Preflight
Server Details
x402 payment preflight for agents: mandate, amount, destination, merchant, expiry and replay.
- Status
- Healthy
- Last Tested
- Transport
- Streamable HTTP · MCP 2025-11-25
- URL
TDQS
Scored across 2 tools
The two tools have sharply distinct roles: one provides free metadata about the preflight service, the other performs the paid verification itself. There is no overlap or ambiguity for an agent choosing between them.
Tool names are both snake_case, but their structure is inconsistent: 'foxify_preflight_info' is a noun-phrase with a server prefix, while 'verify_agent_payment_intent' follows a verb-object pattern without the prefix. This makes the set feel ad hoc rather than systematic.
With only two tools, the server feels minimal, but the tools are directly related to the narrow purpose of payment preflight. It sits at the low end of acceptable scope.
For its stated purpose, the set is complete: the info tool exposes metadata and the verify tool performs the only meaningful action. There are no obvious missing operations within the preflight domain.
Available Tools
2 toolsfoxify_preflight_infoFOXIFY Preflight InfoCInspect
Free metadata for the FOXIFY paid transaction preflight tool.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure, and it fails to carry it. It tells the agent the tool is 'free' but does not say whether it is a read-only query, what data it returns, what fields appear, whether it requires prior setup, or any limits. Behavioral expectations are essentially absent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The single sentence is short, but this is under-specification rather than conciseness. The sentence does not earn its place because 'free metadata' communicates almost nothing actionable; valuable information such as what the metadata contains is omitted.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With no output schema, no annotations, and a sibling tool to differentiate from, the description must explain what 'preflight info' is, what it returns, and when to use it. It does none of this. An agent cannot determine what calling this tool will yield or how it relates to verify_agent_payment_intent.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The tool has zero parameters, so the baseline is 4. With an empty input schema there is nothing to add meaning to, and the description introduces no parameter confusion. This dimension is trivially satisfied.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description does not state a specific verb and resource. 'Free metadata for the FOXIFY paid transaction preflight tool' essentially restates the title ('FOXIFY Preflight Info') and never says what the metadata actually is or what the tool does. The term 'preflight' is left unexplained, and there is no differentiation from the sibling verify_agent_payment_intent.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance is given on when to call this tool versus the sibling verify_agent_payment_intent. There is no stated trigger condition, no context for when preflight info is needed before a transaction, and no example or scenario.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
verify_agent_payment_intentVerify Agent Payment IntentAInspect
Paid transaction preflight. Checks mandate, amount, destination, merchant, expiry and replay risk before an autonomous payment executes. Costs $0.05 USDC on Base.
| Name | Required | Description | Default |
|---|---|---|---|
| agent | No | ||
| nonce | Yes | Unique anti-replay nonce | |
| payment | Yes | ||
| merchant | Yes | ||
| intent_id | Yes | Unique payment-intent identifier | |
| expires_at | Yes | ISO-8601 intent expiry | |
| authorization | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full behavioral burden. It discloses that this is a paid operation with an exact cost of $0.05 USDC on Base, and it enumerates the validation dimensions it performs. It does not describe failure behavior or side effects beyond the fee, but it clearly signals this is a verification step rather than the payment itself.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two tight sentences with no filler. The first sentence front-loads the purpose as a 'paid transaction preflight', and the second adds the essential cost detail. Every word earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity—7 parameters, 6 required, nested objects, no output schema, and no annotations—the description is too thin for correct invocation. It omits how to construct the authorization object, what the preflight response indicates, and what happens on validation failure. It is adequate for tool selection but not for reliable call construction.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 43%, so the description partially compensates by mapping its check list to key parameters: mandate maps to authorization, amount and destination to payment, merchant to merchant, expiry to expires_at, and replay risk to nonce/intent_id. However, it does not explain the nuanced nested fields such as authorization.max_amount, allowed_domains, human_confirmed, or network/currency requirements, leaving a meaningful semantic gap.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly identifies this as a paid preflight tool that 'checks mandate, amount, destination, merchant, expiry and replay risk' before an autonomous payment executes. It uses a specific verb and resource, and the 'before payment executes' framing distinguishes it from an actual payment execution tool. However, it does not explicitly differentiate itself from the sibling foxify_preflight_info.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives clear context for when to use the tool: before an autonomous payment executes, as a preflight check. It does not mention exclusions or when not to use it, and it does not reference the sibling tool or alternative options, but the intended invocation context is explicit enough.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
2 tool updates
- First observed
foxify_preflight_info - First observed
verify_agent_payment_intent
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