> ## Documentation Index
> Fetch the complete documentation index at: https://docs.peaq.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Machine Credit Rating

> A Moody's-style score that summarizes a machine's creditworthiness from its on-chain history.

export const KeyTerms = ({all = {}, ids = [], title = "Key terms in this guide"}) => <details className="not-prose my-4 rounded-xl border border-zinc-200 px-4 py-3 dark:border-zinc-800">
    <summary className="cursor-pointer font-medium text-zinc-900 dark:text-zinc-100">
      {title}
    </summary>
    <div className="mt-3 space-y-2 text-sm text-zinc-700 dark:text-zinc-300">
      {ids.map(id => {
  const t = all[id] || ({});
  return <div key={id}>
            <strong>{t.term}.</strong> {t.def}
          </div>;
})}
    </div>
  </details>;

export const G = {
  onchain: {
    id: "onchain",
    cat: "chain-infra",
    term: "On-chain vs off-chain",
    def: "On-chain means written to the shared public ledger every machine agrees on: permanent and readable by anyone. Off-chain means kept on a normal private server instead."
  },
  blockchain: {
    id: "blockchain",
    cat: "chain-infra",
    term: "Chain / blockchain",
    def: "A shared, tamper-resistant public database maintained by a whole network of computers with no single owner. Different chains are separate such networks."
  },
  peaqChain: {
    id: "peaqChain",
    cat: "chain-infra",
    term: "peaq chain",
    def: "The machine-focused blockchain peaqOS uses as home base for identity and credit records."
  },
  transaction: {
    id: "transaction",
    cat: "chain-infra",
    term: "Transaction (tx) / tx hash",
    def: "A single signed request that changes the ledger. Its hash is a unique, receipt-like ID you can use to look it up later."
  },
  rpcUrl: {
    id: "rpcUrl",
    cat: "chain-infra",
    term: "RPC URL / endpoint",
    def: "The network address your code calls to read from or write to a chain, like the base URL of the chain's API server."
  },
  mainnet: {
    id: "mainnet",
    cat: "chain-infra",
    term: "Mainnet / testnet (agung)",
    def: "Mainnet is the real, live network where tokens have real value. Testnet is a free practice copy with worthless tokens; peaq's is called agung."
  },
  evm: {
    id: "evm",
    cat: "chain-infra",
    term: "EVM / EVM-compatible",
    def: "The Ethereum Virtual Machine: the standard runtime many chains share, so the same 0x... addresses and tools work across all of them. peaq is EVM-compatible."
  },
  node: {
    id: "node",
    cat: "chain-infra",
    term: "Node (RPC node)",
    def: "A server running the blockchain software that holds a copy of the ledger and answers queries. NOT a ROS 2 node, despite the shared word."
  },
  chainId: {
    id: "chainId",
    cat: "chain-infra",
    term: "Chain ID",
    def: "A number that uniquely labels a chain so software doesn't confuse networks (peaq is 3338, Base is 8453)."
  },
  precompile: {
    id: "precompile",
    cat: "chain-infra",
    term: "Precompile",
    def: "A built-in function baked into the chain at a fixed address that acts like a contract but runs as faster native code. The batch one bundles several actions into one all-or-nothing transaction."
  },
  dataHash: {
    id: "dataHash",
    cat: "chain-infra",
    term: "Data hash (keccak256)",
    def: "A short, fixed-length fingerprint of a file, stored on-chain instead of the file itself, so data can be verified later while the raw data stays off-chain."
  },
  wallet: {
    id: "wallet",
    cat: "wallet-keys",
    term: "Wallet",
    def: "An account on the chain, identified by a public address, that holds a machine's funds and approves its actions. Really just a pair of keys, not a place money is stored."
  },
  keypair: {
    id: "keypair",
    cat: "wallet-keys",
    term: "Keypair",
    def: "The two matched secrets behind a wallet: a public address you can share, and a private key you keep secret that signs actions."
  },
  privateKey: {
    id: "privateKey",
    cat: "wallet-keys",
    term: "Private key",
    def: "The secret string that proves you control a wallet. Anyone who has it has full control, like a master password that can never be reset."
  },
  sign: {
    id: "sign",
    cat: "wallet-keys",
    term: "Sign / signature",
    def: "Using your private key to produce a cryptographic stamp proving you approved a specific action, without ever revealing the key."
  },
  signer: {
    id: "signer",
    cat: "wallet-keys",
    term: "Signer / signing identity",
    def: "The wallet whose private key authorizes an action: the account the network treats as the one taking it. NOT a file or an app."
  },
  address: {
    id: "address",
    cat: "wallet-keys",
    term: "Address (0x...)",
    def: "The public 0x... identifier of a wallet or contract you can freely share so others can send to it or look it up, like an account number."
  },
  eoa: {
    id: "eoa",
    cat: "wallet-keys",
    term: "EOA (externally owned account)",
    def: "A plain wallet controlled directly by a private key, as opposed to one controlled by code. Here, the account that IS the machine."
  },
  ows: {
    id: "ows",
    cat: "wallet-keys",
    term: "OWS / wallet vault",
    def: "An open standard for storing wallet keys in an encrypted local file (a vault) with a backup phrase and an activity log, instead of a bare key in a text file."
  },
  passphrase: {
    id: "passphrase",
    cat: "wallet-keys",
    term: "Passphrase (OWS_PASSPHRASE)",
    def: "The password that unlocks the encrypted wallet vault so its key can be used to sign."
  },
  mnemonic: {
    id: "mnemonic",
    cat: "wallet-keys",
    term: "Mnemonic / seed phrase",
    def: "A list of 12 or 24 ordinary words that encodes a wallet's secret key, used to back it up and recover it. Whoever has the words controls the wallet."
  },
  derivation: {
    id: "derivation",
    cat: "wallet-keys",
    term: "Derivation path",
    def: "The deterministic recipe that turns one backup phrase into many specific keys and addresses, one per network or index."
  },
  challenge: {
    id: "challenge",
    cat: "wallet-keys",
    term: "Challenge (sign-to-prove)",
    def: "A login-style handshake: the server sends a random message, you sign it with your key, and the signature proves you control the account without sending the key."
  },
  eip191: {
    id: "eip191",
    cat: "wallet-keys",
    term: "EIP-191 / personal_sign",
    def: "A standard way to sign a plain message to prove you control an account, without sending any on-chain transaction."
  },
  did: {
    id: "did",
    cat: "identity",
    term: "DID / peaqID",
    def: "A globally unique, self-owned ID for a machine that lives on the chain and isn't issued by any single company. peaqID is peaq's version, written did:peaq:0x..."
  },
  register: {
    id: "register",
    cat: "identity",
    term: "Register a machine",
    def: "Putting a machine on the network for the first time, which gives it an ID, a DID, an ownership token, and a locked deposit. registerMachine is self-managed; registerFor is on someone else's behalf."
  },
  machineId: {
    id: "machineId",
    cat: "identity",
    term: "Machine ID",
    def: "The number the network assigns your machine when it registers, used as its handle in every later call."
  },
  ownerOperator: {
    id: "ownerOperator",
    cat: "identity",
    term: "Owner / operator",
    def: "The owner owns a machine; the operator runs it. They can be the same account (self-managed) or different (proxy-managed)."
  },
  proxyOperator: {
    id: "proxyOperator",
    cat: "identity",
    term: "Proxy operator",
    def: "One account that registers and manages many machines on behalf of their owners, so a fleet operator can handle a whole fleet from one wallet."
  },
  didAttributes: {
    id: "didAttributes",
    cat: "identity",
    term: "DID attributes",
    def: "Public name-value facts (a docs link, a data endpoint) attached to a machine's DID and stored on-chain for anyone to read. Writing them is a separate transaction from registration."
  },
  pairing: {
    id: "pairing",
    cat: "identity",
    term: "Pairing / pairing token",
    def: "The verified link between an AI agent and a machine, set up by signing a challenge. The pairing token is the signed credential the agent sends with each request, like a temporary access badge."
  },
  hardwareAttestation: {
    id: "hardwareAttestation",
    cat: "identity",
    term: "Hardware attestation",
    def: "A tamper-resistant chip on the machine cryptographically vouching that it's genuine hardware, so its identity can't be faked in software. This is the Verify layer."
  },
  gas: {
    id: "gas",
    cat: "tokens-economics",
    term: "Gas",
    def: "The small fee, paid in the chain's token, that every action writing to the ledger costs, like a per-write transaction cost."
  },
  peaqToken: {
    id: "peaqToken",
    cat: "tokens-economics",
    term: "PEAQ (token)",
    def: "The peaq network's own token, used to pay gas fees and to lock up as the deposit when registering a machine."
  },
  gasStation: {
    id: "gasStation",
    cat: "tokens-economics",
    term: "Gas Station / faucet",
    def: "A peaq service that hands a brand-new, empty wallet a tiny starting amount of tokens so it can afford its first network fees. Gated by 2FA."
  },
  bond: {
    id: "bond",
    cat: "tokens-economics",
    term: "Bond",
    def: "A refundable deposit (currently 1 PEAQ) you lock up to register a machine, proving skin in the game, like a security deposit. Bonded means the deposit is in place."
  },
  nft: {
    id: "nft",
    cat: "tokens-economics",
    term: "NFT",
    def: "A unique, one-of-a-kind ownership token recorded on the chain. Unlike a coin, no two are interchangeable."
  },
  mint: {
    id: "mint",
    cat: "tokens-economics",
    term: "Mint / minting",
    def: "Creating a brand-new token on the chain and assigning it to an owner, like stamping a fresh serial-numbered certificate into existence."
  },
  machineNft: {
    id: "machineNft",
    cat: "tokens-economics",
    term: "Machine NFT",
    def: "The unique token representing one specific physical machine and its financial profile. It can be sold or bridged on its own, separate from the machine's identity."
  },
  identityNft: {
    id: "identityNft",
    cat: "tokens-economics",
    term: "Identity NFT",
    def: "A non-transferable (soulbound) token minted automatically when a machine registers, representing its identity. Its token ID equals the machine ID."
  },
  tokenId: {
    id: "tokenId",
    cat: "tokens-economics",
    term: "Token ID",
    def: "The unique number identifying one specific token within a collection, like a serial number."
  },
  mcr: {
    id: "mcr",
    cat: "tokens-economics",
    term: "Machine Credit Rating (MCR)",
    def: "A creditworthiness score for a machine (a Moody's-style grade AAA down to NR, plus a 0-100 number) computed from its recorded earnings and activity. Like a credit score for a robot."
  },
  mcrApi: {
    id: "mcrApi",
    cat: "tokens-economics",
    term: "MCR API",
    def: "The public web service you call to fetch a machine's credit score and profile as JSON. No login needed."
  },
  provisioned: {
    id: "provisioned",
    cat: "tokens-economics",
    term: "Provisioned / NR (Not Rated)",
    def: "Early MCR statuses. Provisioned means registered and bonded but with too little history to score yet. NR means no grade, because the score is too low or the machine isn't bonded."
  },
  event: {
    id: "event",
    cat: "tokens-economics",
    term: "Event (revenue / activity)",
    def: "A recorded data point about a machine's work, submitted to the chain to feed its credit score. Revenue events report money earned; activity events report work with no money. NOT a ROS topic message."
  },
  trustLevel: {
    id: "trustLevel",
    cat: "tokens-economics",
    term: "Trust level",
    def: "A label on each submitted event saying how strongly its truth is backed: the machine's word (0), a checkable on-chain record (1), or tamper-proof hardware proof (2)."
  },
  escrow: {
    id: "escrow",
    cat: "tokens-economics",
    term: "Escrow",
    def: "Holding a buyer's payment in a neutral locked place until the service is delivered, then releasing it, so neither side has to trust the other first."
  },
  paymentRail: {
    id: "paymentRail",
    cat: "tokens-economics",
    term: "Payment rail",
    def: "The specific method or channel a payment moves through, like choosing card vs bank transfer vs a particular token."
  },
  x402: {
    id: "x402",
    cat: "tokens-economics",
    term: "x402",
    def: "A web payment standard where a server answers 'payment required' with exact instructions, and the buyer's wallet signs an authorization instead of sending a separate transaction — built for machines and agents paying per request."
  },
  usdt: {
    id: "usdt",
    cat: "tokens-economics",
    term: "USDT",
    def: "A stablecoin token meant to hold a value of one US dollar, used to pay service providers without price swings."
  },
  fractionalize: {
    id: "fractionalize",
    cat: "tokens-economics",
    term: "Fractionalize (ERC-3643)",
    def: "Splitting ownership of one machine into many small tradable shares so multiple people can each own a piece. ERC-3643 is the regulated-securities token standard used to do it."
  },
  smartContract: {
    id: "smartContract",
    cat: "smart-contracts",
    term: "Smart contract / contract address",
    def: "A program deployed on the chain that runs exactly as written and that anyone can call, identified by its own 0x... address."
  },
  registryContracts: {
    id: "registryContracts",
    cat: "smart-contracts",
    term: "Registry contracts",
    def: "On-chain programs that each keep an official, lookup-able list: IdentityRegistry tracks which machines exist, EventRegistry stores their events, IdentityStaking holds their deposits."
  },
  smartAccount: {
    id: "smartAccount",
    cat: "smart-contracts",
    term: "Smart account (ERC-4337)",
    def: "A programmable wallet controlled by code instead of a single key, so it can enforce rules like spending limits. Each machine gets one at activation."
  },
  submitEvent: {
    id: "submitEvent",
    cat: "smart-contracts",
    term: "submitEvent / batchSubmitEvents",
    def: "The calls that record one or many of a machine's revenue or activity entries onto the chain."
  },
  revert: {
    id: "revert",
    cat: "smart-contracts",
    term: "Revert",
    def: "When an on-chain call is rejected and fully undone because a rule was broken, leaving no changes and usually a named error."
  },
  soulbound: {
    id: "soulbound",
    cat: "smart-contracts",
    term: "Soulbound",
    def: "A token that can never be transferred or sold and stays permanently attached to one owner. The Identity NFT is soulbound."
  },
  bridge: {
    id: "bridge",
    cat: "cross-chain",
    term: "Bridge / bridging",
    def: "Moving a token from one chain to another, so the same Machine NFT can exist on a different chain. peaq and Base are live today; bridging is mainnet-only."
  },
  base: {
    id: "base",
    cat: "cross-chain",
    term: "Base",
    def: "Another blockchain network (built by Coinbase) that peaqOS can move Machine NFTs to and from. Paying fees on Base needs Base ETH."
  },
  omniChain: {
    id: "omniChain",
    cat: "cross-chain",
    term: "Omni-chain / cross-chain",
    def: "Working across many separate chains at once, so a machine's identity and credit created on peaq can be read or used on other chains."
  },
  homeChain: {
    id: "homeChain",
    cat: "cross-chain",
    term: "Home chain",
    def: "The chain where a record's canonical, authoritative copy lives. For peaqOS that is peaq chain; every other chain holds a mirror."
  },
  satelliteChain: {
    id: "satelliteChain",
    cat: "cross-chain",
    term: "Satellite chain",
    def: "A chain carrying a read-only, automatically synced mirror of home-chain records, so apps there can use them without crossing back to the home chain."
  },
  sourceChainId: {
    id: "sourceChainId",
    cat: "cross-chain",
    term: "sourceChainId / sourceTxHash",
    def: "Two fields recording which chain an action happened on and its hash there, so a cross-chain event can be traced back and verified."
  },
  machineAgent: {
    id: "machineAgent",
    cat: "general-web3",
    term: "Machine Agent",
    def: "A third-party AI program (Claude, OpenAI, a custom bot) paired to a machine and given limited permission to find, buy, and pay for services on its behalf."
  },
  delegationPolicy: {
    id: "delegationPolicy",
    cat: "general-web3",
    term: "Delegation policy",
    def: "The rules an owner gives an AI agent that cap how much it can spend per transaction and per day and which services it may use, so it transacts within guardrails."
  },
  machineMarkets: {
    id: "machineMarkets",
    cat: "general-web3",
    term: "Machine Markets / Service Registry",
    def: "peaqOS's marketplace where machines list services they offer (Service Registry) and where agents discover, order, pay for, and run services from others."
  },
  sdk: {
    id: "sdk",
    cat: "general-web3",
    term: "SDK (peaq-os-sdk)",
    def: "peaq's code library (Python and JS) you install to call all this functionality without writing low-level blockchain calls yourself."
  },
  stream: {
    id: "stream",
    cat: "data-stream",
    term: "Stream (Data-as-a-Service)",
    def: "The peaqOS function where a machine sells the data it generates: it signs the data, encrypts what's sensitive, and grants buyers access. Selling data, as opposed to selling services (that's Monetize)."
  },
  edgeAgent: {
    id: "edgeAgent",
    cat: "data-stream",
    term: "peaqOS Edge Agent",
    def: "Software that runs on the machine itself (as a ROS 2 node) and signs, encrypts, and ships the data it produces. The on-machine half of Stream."
  },
  dataPackage: {
    id: "dataPackage",
    cat: "data-stream",
    term: "Signed data package",
    def: "A bundle of machine data stamped with the machine's identity (DID, timestamp, sequence number) and a signature, so anyone can prove which machine produced it and that it wasn't altered."
  },
  dataEventMap: {
    id: "dataEventMap",
    cat: "data-stream",
    term: "Data Event Map",
    def: "The policy file a machine owner writes to control what streams out: which topics to read, which fields to keep, drop, or encrypt, and where the signed data goes."
  },
  chunk: {
    id: "chunk",
    cat: "data-stream",
    term: "Chunk",
    def: "A bounded, individually encrypted slice of a data stream (by time window or size). The unit a buyer actually purchases and decrypts."
  },
  chunkChain: {
    id: "chunkChain",
    cat: "data-stream",
    term: "Chunk chain",
    def: "A run of chunks linked in order, each referencing the one before it, so missing, reordered, or edited chunks are detectable. Tamper-evidence for a continuous stream."
  },
  manifest: {
    id: "manifest",
    cat: "data-stream",
    term: "Manifest",
    def: "A signed record describing a chunk or dataset — its hashes, storage location, and encryption details — without the data itself. Buyers verify the manifest before trusting or buying."
  },
  dataset: {
    id: "dataset",
    cat: "data-stream",
    term: "Dataset",
    def: "A group of chunks for one topic and time range, packaged for sale with a single fingerprint (a Merkle root) that covers every chunk in it."
  },
  merkleRoot: {
    id: "merkleRoot",
    cat: "data-stream",
    term: "Merkle root",
    def: "One short hash that stands in for a whole set of items, letting you later prove a specific chunk belongs to a dataset without revealing the rest."
  },
  envelopeEncryption: {
    id: "envelopeEncryption",
    cat: "data-stream",
    term: "Envelope encryption / key wrapping",
    def: "Encrypt the data once with a random key, then lock that key separately for each authorized reader. Granting a buyer access re-locks the key to their public key — the data itself is never re-encrypted."
  },
  accessGrant: {
    id: "accessGrant",
    cat: "data-stream",
    term: "Access grant",
    def: "What a buyer receives after paying: the chunk keys they bought, each locked to their public key. They unlock with their private key and decrypt only those chunks."
  },
  contextProvider: {
    id: "contextProvider",
    cat: "data-stream",
    term: "Context Provider",
    def: "A third party that buys machine data, normalizes it into datasets, and serves or resells it (for example, for AI training). The buyer side of Stream, such as DataHive."
  },
  walrus: {
    id: "walrus",
    cat: "chain-infra",
    term: "Walrus",
    def: "A decentralized storage network where encrypted data chunks can be parked, referenced by walrus:// links. The data stays off the blockchain; only its reference and fingerprint are tracked on-chain."
  },
  solana: {
    id: "solana",
    cat: "cross-chain",
    term: "Solana",
    def: "A high-throughput blockchain. peaqOS wallets can hold a Solana account and sign Solana transactions, and machine-economy payments can settle there."
  }
};

<Tooltip tip={G.mcr.def}>Machine Credit Rating (MCR)</Tooltip> is a letter rating, modeled on traditional credit agencies, that summarizes a machine's financial standing from its <Tooltip tip={G.onchain.def}>on-chain history</Tooltip>.

Any application can query a machine's MCR through the public [MCR API](/peaqos/api-reference/overview): no authentication, no permissions. It travels with the machine across chains.

<KeyTerms all={G} ids={["mcr", "onchain", "register", "bond", "provisioned", "event", "trustLevel"]} />

## Rating scale

MCR ratings use a familiar AAA-to-NR scale. The integer `mcr_score` (0-100, rounded) maps to a letter via fixed thresholds:

| Rating          | `mcr_score` | Meaning                                            |
| :-------------- | :---------- | :------------------------------------------------- |
| **AAA**         | ≥ 95        | Highest credit quality                             |
| **AA**          | ≥ 85        | Very high credit quality                           |
| **A**           | ≥ 75        | High credit quality                                |
| **BBB**         | ≥ 60        | Investment grade                                   |
| **BB**          | ≥ 45        | Below investment grade                             |
| **B**           | ≥ 30        | Minimum rated                                      |
| **NR**          | 0           | Not rated. Score below 30, or machine is unbonded  |
| **Provisioned** | 0           | Newly registered. Not enough history to score yet. |

Both `NR` and `Provisioned` return `mcr_score = 0`; the `mcr` letter and `bond_status` field on `/mcr/{did}` distinguish the two.

## Lifecycle: Provisioned graduation

A freshly <Tooltip tip={G.register.def}>registered</Tooltip>, <Tooltip tip={G.bond.def}>bonded</Tooltip> machine is <Tooltip tip={G.provisioned.def}>**Provisioned**</Tooltip>: on-chain, but not yet rated. It graduates onto the rated scale once it has both:

* **Enough events:** a sustained set of qualifying <Tooltip tip={G.event.def}>events</Tooltip>. Activity-only machines (sensors, drones without revenue) can graduate via activity alone; revenue is not required.
* **Enough history:** the first-to-last event span covers a sustained operating window.

Until both gates are cleared the machine returns `mcr: "Provisioned"` with `mcr_score: 0`, regardless of how strong the underlying activity is.

Ratings are not assigned. They're earned. A machine's standing reflects what it has done on-chain.

## How the score is computed

The MCR server fetches every event from the `EventRegistry`, normalizes revenue values to USD cents via FX at the event's timestamp, and combines them into a `0`–`100` integer score that maps to a letter rating. The exact weighting is not published.

The score is built from a small set of inputs:

**Bond.** Every bonded machine receives a baseline contribution. An unbonded machine returns `(0, "NR")` immediately. Bond is the floor for any score at all.

**Revenue and activity.** Two factors derived from the event history. Each rewards consistency (regular cadence), depth (sustained activity over many events), and tenure (longer-running machines). Revenue is daily-aggregated: events are summed per UTC calendar day, and only days that meet a minimum economic threshold count toward revenue.

**<Tooltip tip={G.trustLevel.def}>Trust level</Tooltip>.** Per-event trust tiers, with revenue events weighted by economic value. Higher tiers contribute more; `0` self-reported, `1` on-chain verifiable, `2` hardware-signed. See [Trust levels](/peaqos/concepts/trust-levels).

A long-running self-reported machine earns a small graduation bonus on its trust contribution after sustained operation, but it remains below the on-chain tier.

**Freshness.** Recency decay applied to the trust contribution. A machine that hasn't reported recently scores progressively lower; a sustained dormancy gap clamps freshness at a floor until the machine demonstrates renewed activity over a recovery window. Recovery is earned, not granted by a single recent event.

**Negative event flag.** While an active flag is set on the machine, the trust contribution is reduced for a fixed window from the flag timestamp; the penalty expires automatically after the window closes.

The final score is clamped to `[0, 100]` and rounded to an integer before mapping to a letter.

## Revenue trend

`/mcr/{did}` exposes a `revenue_trend` field with one of four values, derived from short-term vs longer-term moving averages over qualifying revenue events:

| Value            | Meaning                                                     |
| :--------------- | :---------------------------------------------------------- |
| `"up"`           | Recent revenue is materially above the longer-term baseline |
| `"stable"`       | Recent revenue tracks the longer-term baseline              |
| `"down"`         | Recent revenue is materially below the longer-term baseline |
| `"insufficient"` | Not enough qualifying revenue events to compute a trend     |

## Multi-currency revenue

Revenue events submitted in any ISO 4217 currency get FX-normalized to USD by the MCR server before scoring. Pass `currency` directly to `submitEvent` and supply `value` as the currency's minor-unit integer (cents for USD/HKD, whole units for JPY/KRW); the server fetches the historical rate at the event's `timestamp` and stores both `origin_value` and the computed `usd_value` (USD cents). Two distinct degradation paths show up on the wire:

* **Unsupported currency.** The per-event `amount_status` becomes `"unsupported_currency"`. The revenue value is ignored when scoring (treated as \$0). This is a partner-input error, not infra failure, so it does **not** flip `mcr_degraded`.
* **FX infrastructure failure.** When the MCR server has to fall back to a stale snapshot (`fx_source = "stale_latest"`) or has no FX at all (`fx_source = "default_usd_fx_outage"`), the event's `amount_status` becomes `"fx_unavailable"` **and** the top-level `mcr_degraded: true` flag flips on `/mcr/{did}`, so consumers can distinguish a degraded score from a quiet machine.

See [Submit events: currency and value units](/peaqos/guides/submit-events#currency-and-value-units).

## Cross-links

* [Events](/peaqos/concepts/events): the revenue and activity records that feed MCR
* [Trust levels](/peaqos/concepts/trust-levels): what each `trust_level` means at submit time
* [GET /mcr/\{did}](/peaqos/api-reference/get-mcr): fetch a machine's current rating
* [Qualify function](/peaqos/functions/qualify): the function that exposes MCR end-to-end