FiatDock

Stablecoin intelligence ($0.002)

stablecoin_intel

Read-onlyIdempotent

PAID ($0.002 USDC via x402). Supply, peg health and per-chain breakdown for USDC and other stablecoins: total circulating supply, deviation from the $1.00 peg, peg mechanism, the amount circulating on Base (with its share of total) and the top chains by supply (DefiLlama). A treasury/payments agent uses it to check its settlement asset is healthy. Without payment this returns the 402 challenge; the fiatdock-mcp npm package pays automatically.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`asset`	No	Stablecoin symbol (default USDC), e.g. USDC, USDT, DAI, USDe
`payment`	No	Base64 of a single x402 v2 PaymentPayload (EIP-3009 transferWithAuthorization on Base USDC). OMIT it on the first call: the 402 you get back carries `howToPay.payloadTemplate` — the exact envelope to fill in — plus the price and the EIP-712 domain. Send it on the second call to complete the purchase; it is forwarded as the PAYMENT-SIGNATURE header, never as body data. Nothing is charged for the 402 itself, and a call that fails after payment settles nothing.

Output Schema

TableJSON Schema

Name	Required	Description
`asOf`	Yes	ISO 8601 time the snapshot was read
`name`	No	Stablecoin full name
`note`	No	Human-readable caveat about the snapshot, if any
`asset`	Yes	Stablecoin symbol
`price`	Yes	Current price in USD
`onBase`	Yes	Circulating supply on Base + its share of total
`source`	Yes	Data source (e.g. DefiLlama)
`pegType`	No	What the asset is pegged to (e.g. peggedUSD)
`pegStatus`	Yes	on-peg \| slight-deviation \| off-peg \| unknown
`topChains`	Yes	Top chains by circulating supply
`pegMechanism`	No	e.g. fiat-backed, crypto-backed, algorithmic
`pegDeviationPct`	Yes	Absolute deviation from the peg, % (from $1.00 for a USD stablecoin; for another peg, measured against that currency's USD rate; null when unknown)
`totalCirculatingUsd`	Yes	Total circulating supply (USD)

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedSep 25, 2026

changedOutput schema / properties / pegDeviationPct / description

Previous value: -"Absolute deviation from $1.00, %"New value: +"Absolute deviation from the peg, % (from $1.00 for a USD stablecoin; for another peg, measured against that currency's USD rate; null when unknown)"

Changed1 schema field changedAug 23, 2026

addedInput schema / properties / payment

Added value: +{
+  "description": "Base64 of a single x402 v2 PaymentPayload (EIP-3009 transferWithAuthorization on Base USDC). OMIT it on the first call: the 402 you get back carries `howToPay.payloadTemplate` — the exact envelope to fill in — plus the price and the EIP-712 domain. Send it on the second call to complete the purchase; it is forwarded as the PAYMENT-SIGNATURE header, never as body data. Nothing is charged for the 402 itself, and a call that fails after payment settles nothing.",
+  "type": "string"
+}

Changed1 schema field changedJul 29, 2026

addedOutput schema / properties / pegType

Added value: +{
+  "description": "What the asset is pegged to (e.g. peggedUSD)",
+  "type": "string"
+}

Changed4 schema fields changedJul 5, 2026
- addedOutput schema / properties / asOf / description
```
Added value: +"ISO 8601 time the snapshot was read"
```
- addedOutput schema / properties / name / description
```
Added value: +"Stablecoin full name"
```
- addedOutput schema / properties / note / description
```
Added value: +"Human-readable caveat about the snapshot, if any"
```
- addedOutput schema / properties / source / description
```
Added value: +"Data source (e.g. DefiLlama)"
```
AddedJun 22, 2026

TDQS

A4.7/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description discloses the paid nature, exact price, the 402-challenge response when payment is omitted, and that the fiatdock-mcp package pays automatically. This adds payment/auth behavior far beyond the readOnly/openWorld/idempotent annotations and matches them. It also names DefiLlama as the data source.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences with no filler: the paid warning is front-loaded, the data scope is compactly listed, and the 402/payment behavior is stated in one final sentence. Every sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a two-parameter tool with an output schema and rich parameter descriptions, the description covers the essential missing context: cost, payment flow, and intended use. Nothing an agent needs to decide whether to call it is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already covers 100% of the parameters, so the baseline is 3. The description adds useful context beyond the schema by stating the price, the paid x402 flow, and what data the tool returns (supply, peg, chains), which gives the optional asset and payment parameters operational meaning.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific purpose: assessing stablecoin supply, peg health, and per-chain breakdown for USDC and other stablecoins. It lists exact data points (total supply, peg deviation, Base circulation, top chains), which clearly separates it from price/safety/wallet-balance siblings. The treasury/payments use case adds a concrete operational purpose.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It explicitly frames when to use the tool: a treasury/payments agent checking whether its settlement asset is healthy. It does not list exclusions or alternatives (e.g., use token_price for market price), so it misses the explicit when-not guidance needed for a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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