MCP Tool Descriptor Lint
Lint a supplied MCP tool descriptor for a bounded naming profile, description quality, object-root input/output schemas and typed annotation hints. Unsupported schemas produce explicit findings. Annotations are untrusted hints; this is neither full MCP protocol validation nor a security decision.
api-assurance · Operation ID: mcp-tool-lint
Choose this operation when
- Review tool descriptors before adding them to an agent catalogue
- Identify schema limitations and untrusted annotation hints
Outside this profile
- MCP transport/protocol conformance certification
- Trusting readOnlyHint as an authorization guarantee
Exact release references
Static JSON contract · Markdown reference · Fixed example response
Complete input schema
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"tool": {
"$ref": "#/$defs/__schema0"
}
},
"required": [
"tool"
],
"additionalProperties": false,
"$defs": {
"__schema0": {
"anyOf": [
{
"type": "string"
},
{
"type": "number"
},
{
"type": "boolean"
},
{
"type": "null"
},
{
"type": "array",
"items": {
"$ref": "#/$defs/__schema0"
}
},
{
"type": "object",
"propertyNames": {
"type": "string"
},
"additionalProperties": {
"$ref": "#/$defs/__schema0"
}
}
]
}
}
}
Complete output-envelope schema
{
"type": "object",
"required": [
"operation",
"version",
"result",
"provenance"
],
"properties": {
"operation": {
"const": "mcp-tool-lint",
"type": "string"
},
"version": {
"const": "0.29.0",
"type": "string"
},
"result": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"profile": {
"type": "string",
"const": "mcp-tool-descriptor-lint-v1"
},
"passesChecks": {
"type": "boolean"
},
"complete": {
"type": "boolean",
"const": false
},
"schemaSupported": {
"type": "boolean"
},
"findings": {
"maxItems": 200,
"type": "array",
"items": {
"type": "object",
"properties": {
"code": {
"type": "string"
},
"severity": {
"type": "string",
"enum": [
"error",
"warning",
"unsupported"
]
},
"path": {
"type": "string"
},
"message": {
"type": "string"
},
"suggestion": {
"type": "string"
}
},
"required": [
"code",
"severity",
"path",
"message",
"suggestion"
],
"additionalProperties": false
}
},
"findingCount": {
"type": "integer",
"minimum": 0,
"maximum": 9007199254740991
},
"truncated": {
"type": "boolean"
}
},
"required": [
"profile",
"passesChecks",
"complete",
"schemaSupported",
"findings",
"findingCount",
"truncated"
],
"additionalProperties": false
},
"provenance": {
"type": "object",
"required": [
"inputSha256",
"outputSha256",
"deterministic",
"externalRequests"
],
"properties": {
"inputSha256": {
"type": "string",
"pattern": "^[a-f0-9]{64}$"
},
"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
{
"tool": {
"name": "get_order",
"description": "Read a single order by ID",
"inputSchema": {
"type": "object",
"required": [
"id"
],
"properties": {
"id": {
"type": "integer"
}
},
"additionalProperties": false
},
"annotations": {
"readOnlyHint": true,
"openWorldHint": false
}
}
}
Example response
{
"operation": "mcp-tool-lint",
"version": "0.29.0",
"result": {
"profile": "mcp-tool-descriptor-lint-v1",
"passesChecks": true,
"complete": false,
"schemaSupported": true,
"findings": [
{
"code": "ANNOTATIONS_UNTRUSTED",
"severity": "warning",
"path": "/tool/annotations",
"message": "Annotations are hints and cannot establish authorization or safety",
"suggestion": "Verify tool behavior and enforce permissions independently"
}
],
"findingCount": 1,
"truncated": false
},
"provenance": {
"inputSha256": "f66182b11adf2e7a4e3a849f0df9edd8d3045eae4ccea501d2b2e9a7d491f31c",
"outputSha256": "6c4e2538aeec9993abca6cba4ccddc9e47a5a1a7f2e4836c55d4ff5380d13ce2",
"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": 110000,
"jsonNodes": 10000,
"depth": 24,
"schemaNodes": 128,
"schemaDepth": 12,
"schemaProperties": 64,
"findings": 200,
"outputBytes": 450000,
"jsonPointerCharacters": 4096
}
}
Complete schemas, descriptions and cross-field validation may impose additional limits.
Proposed price and protocol definitions
{
"unit": "one successful operation call",
"proposedNominalUsd": "0.01",
"sixDecimalTokenBaseUnits": "10000",
"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/mcp-tool-lint",
"mpp": "/v1/mpp/mcp-tool-lint"
}
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.