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FunctionToolCallSerializer

This docs was updated at: 2026-03-21

com.paragon.responses.json.FunctionToolCallSerializer  ยท  Class

Extends StdSerializer<FunctionToolCall>

Custom Jackson serializer for FunctionToolCall.

When FunctionToolCall appears in a List (which uses @JsonTypeInfo(EXISTING_PROPERTY)), the outer type resolver does NOT inject the "type" field. Without this serializer, the serialized JSON lacks "type": "function_call", causing OpenRouter to reject the payload.

This serializer explicitly writes "type": "function_call" along with all other fields.

Methods

serializeWithType

public void serializeWithType(
      FunctionToolCall value,
      JsonGenerator gen,
      SerializationContext provider,
      TypeSerializer typeSer)
      throws tools.jackson.core.JacksonException

Called when serializing within a polymorphic context (e.g., List with @JsonTypeInfo). We embed "type" directly in the JSON object, so skip the external type wrapper and delegate to .serialize.