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MCP TypeScript SDK (V2) / @modelcontextprotocol/client / ext/skills/errors

ext/skills/errors ​

Classes ​

SkillVerificationError ​

Defined in: packages/client/src/ext/skills/errors.ts:11

A skill file failed verification against its skill entry: not listed, wrong size, wrong digest, or (for SKILL.md) frontmatter that differs from the entry. Hosts must not load the file; for SKILL.md, not the skill.

Extends ​

Constructors ​

Constructor ​

new SkillVerificationError(reason, uri, message, differences?, options?): SkillVerificationError

Defined in: packages/client/src/ext/skills/errors.ts:21

Parameters ​
reason ​

SkillVerificationReason

uri ​

string

message ​

string

differences? ​

readonly string[] = []

options? ​

ErrorOptions

Returns ​

SkillVerificationError

Overrides ​

SdkError.constructor

Properties ​

cause? ​

optional cause?: unknown

Defined in: node_modules/.pnpm/typescript@5.9.3/node_modules/typescript/lib/lib.es2022.error.d.ts:26

Inherited from ​

SdkError.cause

code ​

readonly code: SdkErrorCode

Defined in: packages/core-internal/src/errors/sdkErrors.ts:158

Stable string code identifying the failure (SdkErrorCode).

Inherited from ​

SdkError.code

data? ​

readonly optional data?: unknown

Defined in: packages/core-internal/src/errors/sdkErrors.ts:160

Optional structured payload (for example the HTTP status carried by SdkHttpError). Opaque to the SDK: a cause key inside data is not promoted to Error.cause.

Inherited from ​

SdkError.data

differences ​

readonly differences: readonly string[]

Defined in: packages/client/src/ext/skills/errors.ts:19

For frontmatter: one line per differing field.

message ​

message: string

Defined in: node_modules/.pnpm/typescript@5.9.3/node_modules/typescript/lib/lib.es5.d.ts:1077

Inherited from ​

SdkError.message

name ​

name: string

Defined in: node_modules/.pnpm/typescript@5.9.3/node_modules/typescript/lib/lib.es5.d.ts:1076

Inherited from ​

SdkError.name

reason ​

readonly reason: SkillVerificationReason

Defined in: packages/client/src/ext/skills/errors.ts:16

stack? ​

optional stack?: string

Defined in: node_modules/.pnpm/typescript@5.9.3/node_modules/typescript/lib/lib.es5.d.ts:1078

Inherited from ​

SdkError.stack

uri ​

readonly uri: string

Defined in: packages/client/src/ext/skills/errors.ts:17

stackTraceLimit ​

static stackTraceLimit: number

Defined in: node_modules/.pnpm/@types+node@24.12.0/node_modules/@types/node/globals.d.ts:68

The Error.stackTraceLimit property specifies the number of stack frames collected by a stack trace (whether generated by new Error().stack or Error.captureStackTrace(obj)).

The default value is 10 but may be set to any valid JavaScript number. Changes will affect any stack trace captured after the value has been changed.

If set to a non-number value, or set to a negative number, stack traces will not capture any frames.

Inherited from ​

SdkError.stackTraceLimit

Methods ​

[hasInstance]() ​

static [hasInstance](value): boolean

Defined in: packages/core-internal/src/errors/sdkErrors.ts:125

Parameters ​
value ​

unknown

Returns ​

boolean

Inherited from ​

SdkError.[hasInstance]

captureStackTrace() ​

static captureStackTrace(targetObject, constructorOpt?): void

Defined in: node_modules/.pnpm/@types+node@24.12.0/node_modules/@types/node/globals.d.ts:52

Creates a .stack property on targetObject, which when accessed returns a string representing the location in the code at which Error.captureStackTrace() was called.

js
const myObject = {};
Error.captureStackTrace(myObject);
myObject.stack;  // Similar to `new Error().stack`

The first line of the trace will be prefixed with ${myObject.name}: ${myObject.message}.

The optional constructorOpt argument accepts a function. If given, all frames above constructorOpt, including constructorOpt, will be omitted from the generated stack trace.

The constructorOpt argument is useful for hiding implementation details of error generation from the user. For instance:

js
function a() {
  b();
}

function b() {
  c();
}

function c() {
  // Create an error without stack trace to avoid calculating the stack trace twice.
  const { stackTraceLimit } = Error;
  Error.stackTraceLimit = 0;
  const error = new Error();
  Error.stackTraceLimit = stackTraceLimit;

  // Capture the stack trace above function b
  Error.captureStackTrace(error, b); // Neither function c, nor b is included in the stack trace
  throw error;
}

a();
Parameters ​
targetObject ​

object

constructorOpt? ​

Function

Returns ​

void

Inherited from ​

SdkError.captureStackTrace

isError() ​

static isError(error): error is Error

Defined in: node_modules/.pnpm/typescript@5.9.3/node_modules/typescript/lib/lib.esnext.error.d.ts:23

Indicates whether the argument provided is a built-in Error instance or not.

Parameters ​
error ​

unknown

Returns ​

error is Error

Inherited from ​

SdkError.isError

isInstance() ​

static isInstance<T>(this, value): value is InstanceType<T>

Defined in: packages/core-internal/src/errors/sdkErrors.ts:138

Brand-based type guard: equivalent to value instanceof this, as an explicit static predicate (the axios/AWS-SDK isInstance style). Reads the caller's own brand via this, so every branded subclass gets a correctly-scoped guard by inheritance. Must be invoked on the class — in callback position write v => SdkError.isInstance(v), not .filter(SdkError.isInstance) (detached calls throw rather than silently matching nothing).

Type Parameters ​
T ​

T extends (...args) => unknown

Parameters ​
this ​

T

value ​

unknown

Returns ​

value is InstanceType<T>

Inherited from ​

SdkError.isInstance

prepareStackTrace() ​

static prepareStackTrace(err, stackTraces): any

Defined in: node_modules/.pnpm/@types+node@24.12.0/node_modules/@types/node/globals.d.ts:56

Parameters ​
err ​

Error

stackTraces ​

CallSite[]

Returns ​

any

See ​

https://v8.dev/docs/stack-trace-api#customizing-stack-traces

Inherited from ​

SdkError.prepareStackTrace

Type Aliases ​

SkillVerificationReason ​

SkillVerificationReason = "unlisted" | "size" | "digest" | "frontmatter"

Defined in: packages/client/src/ext/skills/errors.ts:4

Why a skill file failed verification.