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Defined in: server/middleware.ts:203 Normalises errors thrown by handlers to proper MCP shapes:
  • tools/call plain errors → { isError: true, content: […] } (per MCP spec)
  • tools/call McpError → re-thrown as a protocol-level error
  • all other methods → McpError(InternalError, message)
Re-throwing McpError from onCallTool ensures that middleware-level errors (e.g. from RateLimitingMiddleware or SizeLimitingMiddleware stacked before this middleware) always propagate as protocol errors and are never silently converted to isError:true tool responses.

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Implements

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Constructors

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Constructor

new ErrorNormalizationMiddleware(): ErrorNormalizationMiddleware;

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Returns

ErrorNormalizationMiddleware

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Methods

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onCallTool()

onCallTool<T, R>(ctx, next): Promise<R>;
Defined in: server/middleware.ts:204

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Type Parameters

T
T
R
R

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Parameters

ctx
MiddlewareContext<T>
next
Next<R>

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Returns

Promise<R>

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Implementation of

Middleware.onCallTool

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onRequest()

onRequest<T, R>(ctx, next): Promise<R>;
Defined in: server/middleware.ts:216

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Type Parameters

T
T
R
R

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Parameters

ctx
MiddlewareContext<T>
next
Next<R>

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Returns

Promise<R>

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Implementation of

Middleware.onRequest