HTTP Entity-Tag Preconditions
Evaluate supplied If-Match and If-None-Match against caller-asserted representation existence/current ETag, preserving strong/weak comparison and precondition order. Gives conditional 304/412 or proceed guidance only. Excludes date/range/freshness, duplicate-write exceptions, permission decisions and live requests.
protocol-assurance · Operation ID: http-etag-evaluate
Choose this operation when
- Evaluate conditional HTTP ETag cache validation and optimistic concurrency preconditions
- Distinguish weak If-None-Match from strong If-Match and wildcard existence
Outside this profile
- Cache freshness, date validators, HTTP ranges, fetching resources or deciding replay authorization
- Guaranteed success status or inferring current representation from an ETag alone
Exact release references
Static JSON contract · Markdown reference · Fixed example response
Complete input schema
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"method": {
"type": "string",
"minLength": 1,
"maxLength": 32
},
"representationExists": {
"type": "boolean"
},
"currentEtag": {
"type": "string",
"maxLength": 4096
},
"ifMatch": {
"type": "string",
"maxLength": 16000
},
"ifNoneMatch": {
"type": "string",
"maxLength": 16000
}
},
"required": [
"method",
"representationExists"
],
"additionalProperties": false
}
Complete output-envelope schema
{
"type": "object",
"required": [
"operation",
"version",
"result",
"provenance"
],
"properties": {
"operation": {
"const": "http-etag-evaluate",
"type": "string"
},
"version": {
"const": "0.29.0",
"type": "string"
},
"result": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"profile": {
"type": "string",
"const": "http-entity-tag-preconditions-v1"
},
"decision": {
"type": "string",
"enum": [
"proceed",
"not-modified",
"precondition-failed"
]
},
"suggestedStatus": {
"anyOf": [
{
"type": "number",
"const": 304
},
{
"type": "number",
"const": 412
},
{
"type": "null"
}
]
},
"evaluated": {
"type": "array",
"items": {
"type": "object",
"properties": {
"field": {
"type": "string",
"enum": [
"if-match",
"if-none-match"
]
},
"comparison": {
"type": "string",
"enum": [
"strong",
"weak"
]
},
"passes": {
"type": "boolean"
}
},
"required": [
"field",
"comparison",
"passes"
],
"additionalProperties": false
}
},
"assumptions": {
"type": "array",
"items": {
"type": "string"
}
}
},
"required": [
"profile",
"decision",
"suggestedStatus",
"evaluated",
"assumptions"
],
"additionalProperties": false
},
"provenance": {
"type": "object",
"required": [
"inputSha256",
"outputSha256",
"deterministic",
"externalRequests"
],
"properties": {
"inputSha256": {
"type": "string",
"pattern": "^[a-f0-9]{64}$"
},
"outputSha256": {
"type": "string",
"pattern": "^[a-f0-9]{64}$"
},
"deterministic": {
"const": true
},
"externalRequests": {
"const": 0
}
}
}
},
"additionalProperties": false
}
Fixed example
One accepted fixed example, not a custom-input trial. No operation runs when this static page is requested.
Example input
{
"method": "GET",
"representationExists": true,
"currentEtag": "\"revision-7\"",
"ifNoneMatch": "W/\"revision-7\""
}
Example response
{
"operation": "http-etag-evaluate",
"version": "0.29.0",
"result": {
"profile": "http-entity-tag-preconditions-v1",
"decision": "not-modified",
"suggestedStatus": 304,
"evaluated": [
{
"field": "if-none-match",
"comparison": "weak",
"passes": false
}
],
"assumptions": [
"Normal request checks already succeeded; only If-Match and If-None-Match are evaluated",
"Representation selection/existence and current entity-tag are caller assertions",
"No date/range/cache-freshness checks, duplicate-write exception, authorization, or network request",
"Proceed means these supplied preconditions permit continuing normal request processing, not guaranteed success"
]
},
"provenance": {
"inputSha256": "728b21287315350b2cb828a2620f4e94542eab7bfee981d92d0d2545b552a41d",
"outputSha256": "1d723e87ba064217415f2ce5bc9d80034d6a00b041f831924a89bcd55c27e04a",
"deterministic": true,
"externalRequests": 0
}
}
Bounds and precision
JavaScript IEEE-754 numbers; use strings for large integer IDs/exact decimals where the schema accepts strings. No lossless numeric parsing.
{
"global": {
"requestBytes": 131072,
"responseBytes": 524288,
"jsonDepth": 32,
"jsonNodes": 20000,
"requestsPerMinute": 60,
"paidAttemptsPerMinute": 20,
"idempotencyHours": 24
},
"operation": {
"inputBytes": 100000,
"outputBytes": 400000,
"jsonNodes": 12000,
"depth": 20,
"findings": 150,
"findingJsonBytes": 300000,
"tagsPerField": 200,
"fieldCharacters": 16000
}
}
Complete schemas, descriptions and cross-field validation may impose additional limits.
Proposed price and protocol definitions
{
"unit": "one successful operation call",
"proposedNominalUsd": "0.003",
"sixDecimalTokenBaseUnits": "3000",
"subscription": false,
"includesPayerWalletOrNetworkFees": false,
"liveQuoteVerified": false,
"condition": "Actual SDK challenge is authoritative only within the caller's explicit authorization; configured six-decimal token peg is an operator assertion, not a conversion guarantee."
}
Protocol definitions: x402, mpp. MPP uses Tempo charge. Paid MCP execution is unsupported. All runtime readiness is not evaluated in this build.
API path templates, not endpoints on this documentation host
{
"x402": "/v1/x402/http-etag-evaluate",
"mpp": "/v1/mpp/http-etag-evaluate"
}
Required headers
{
"Content-Type": "application/json",
"Idempotency-Key": "random 16–128 character operation identifier"
}
Actual SDK challenge amount, asset, network, recipient and wallet costs must pass independent authorization. Preserve identical key, body, protocol and credential on retries; on PAYMENT_UNCERTAIN stop and reconcile.
Execution profile and provider conditions
{
"deterministic": true,
"externalRequests": 0,
"maxExternalRequests": 0,
"resultSnapshotPersisted": false,
"fixedExampleIsIllustrativeSnapshot": false,
"requiresPayment": true,
"supportsMcpExecution": false
}
Deterministic supplied-input operation with no external requests or stored request/result bodies. Payment infrastructure retains payment metadata and hashes.
Failure handling
- HTTP 400: Malformed JSON, missing/invalid idempotency key, or payment identifier mismatch Correct the request before payment
- HTTP 402: Payment challenge or rejected payment Use official protocol SDK; inspect payment outcome before another payment
- HTTP 409: Idempotency conflict, duplicate proof, or PAYMENT_UNCERTAIN Keep original key, body, and proof; reconcile uncertainty with operator; never blindly repay
- HTTP 413: Input or generated output too large Reduce input; no payment attempted for validation failure
- HTTP 415: Unsupported media type or compression Send uncompressed application/json
- HTTP 422: Schema or service-specific semantic validation failure Correct input using returned error code; no payment attempted
- HTTP 429: Request/payment-attempt rate exceeded Wait for rate limit window; preserve existing payment identity
- HTTP 503: Payment configuration/provider/state unavailable, or live DNS preparation failed before settlement Check readiness; DNS preparation failures may retry the identical key/body/credential only; uncertainty requires reconciliation
Declared requirements
Before any paid call, refresh the live operation contract and POST the complete bounded budgeted plan to the separate API's /preflight. Unknown requirements block selection; compatible preflight is not permission to spend.