in, out and inout is the correct option for the direction property in the function.json file.

The direction property accepts in for input bindings, out for output bindings and inout for bindings that can act as both input and output. The runtime uses these values to determine the data flow for each binding listed in the function.json file.

blob, queue, table, file are examples of binding types or storage resources and not valid values for the direction property because the property expects flow semantics rather than resource names.

stderr, stdout, stdin refer to standard IO streams and are unrelated to Azure Functions binding directions so they are not valid direction values.

left and right are not meaningful in Azure Functions configuration and are not valid options for the direction property.

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