Glossary

Every term used across these docs, defined in one or two sentences. Terms are capitalised in the docs when they refer to a specific protocol object, such as a Probe or an Attestation, and lower-cased when used in the ordinary sense. Entries are alphabetical.

A–E

Attestation

A single Probe or escrowed-call result published onchain by a Watcher: uptime, latency, schema validity, and quoted versus charged price for one request to one endpoint. Attestations are the raw material of every Endpoint Score.

Base

The Ethereum layer-two network on which VIGIL runs. Attestations, scores, escrow, and USDC payments all settle on Base.

Check

One of the four mechanical tests applied to a response: schema validity, response size, deadline, and price integrity. A response must pass all four for escrow to release.

Deadline

The maximum time an agent allows a provider to respond, set per call, default 30 s and at most 300 s. An escrow with no response by the deadline is refunded automatically.

Dispute

A challenge to an Attestation or escrow outcome, opened by any staked Watcher within 24 h and settled by a stake-weighted vote of active Watchers over 48 h. The losing side is slashed.

Endpoint Score

A public number from 0 to 100 for one x402 endpoint, computed as a stake-weighted, time-decayed mean of Attestations and written to the ERC-8004 reputation registry. Bands: 90–100 Reliable, 70–89 Acceptable, 40–69 Degraded, below 40 Unreliable.

ERC-8004

The Ethereum standard for agent identity and reputation registries. VIGIL writes Endpoint Scores to its Reputation Registry and reads its Identity Registry to resolve a provider.

Escrow

The contract that holds an agent's USDC between payment and settlement. It moves through the states Quoted, Locked, Responded, Checked, and then Released, Refunded, or Disputed.

F–P

Facilitator

In x402, the service that verifies and settles a payment on the payer's behalf. The VIGIL Facilitator is a drop-in x402 facilitator that routes the payment into escrow and runs the checks instead of paying the provider directly.

Price integrity

The check that the amount charged for a response equals the amount quoted in the 402 response. A mismatch fails the call and counts against the endpoint's score.

Probe

A paid, real x402 call made by a Watcher to measure an endpoint. The reference Probe calls each endpoint every 60 s from at least 3 regions and spends the endpoint's quoted price per call.

Provider

The operator of an x402 endpoint that sells responses for USDC. Providers are scored whether or not they participate, and may optionally subscribe to VIGIL Verified.

Q–Z

Refund

The escrow outcome in which the agent's USDC is returned because the response failed a check or never arrived. Refunds are automatic and require no claim.

Release

The escrow outcome in which the provider receives the agent's USDC, less the protocol fee, because the response passed all four checks within the deadline.

Schema validity

The check that a response parses and conforms to the schema the endpoint declares. A response that is empty, malformed, or the wrong shape fails this check.

Slashing

The forfeit of a fraction of a Watcher's staked $VIGIL, in an amount defined by governance, when a dispute is resolved against its Attestations. Slashing is the enforcement mechanism behind every score.

Stake

$VIGIL locked by a Watcher as a bond. Stake determines a Watcher's weight in scoring and disputes, subject to a per-Watcher cap of 10% of total weight per endpoint, and is what slashing takes from.

USDC

The dollar-denominated stablecoin in which every x402 payment, escrow, refund, release, and protocol fee is denominated. $VIGIL is never used for payment.

VIGIL Verified

An optional paid badge for providers whose endpoints hold a Reliable score. The subscription is one of VIGIL's two fee sources and has no effect on the score itself.

Watcher

Anyone who stakes $VIGIL and runs Probes. Watchers publish Attestations, vote on disputes, earn attestation rewards and 50% of protocol fees, and are slashed for false Attestations.

x402

The HTTP payment protocol in which a server answers a request with status 402 Payment Required, the client pays in USDC, and the server then returns the response. VIGIL adds quality control to this flow without changing it.