API: Request Parameters & Response Metadata

public class BedrockChatRequestParameters extends DefaultChatRequestParameters {
    public static final BedrockChatRequestParameters EMPTY;

    // Bedrock-specific accessors
    public Map<String, Object> additionalModelRequestFields();
    public BedrockCachePointPlacement cachePointPlacement();
    public BedrockGuardrailConfiguration bedrockGuardrailConfiguration();

    // Composition
    public BedrockChatRequestParameters overrideWith(ChatRequestParameters that);
    public BedrockChatRequestParameters defaultedBy(ChatRequestParameters that);

    // Builder
    public static Builder builder();
}

public static class Builder extends DefaultChatRequestParameters.Builder<Builder> {
    // Standard parameters (inherited)
    public Builder temperature(Double temperature);
    public Builder topP(Double topP);
    public Builder topK(Integer topK);
    public Builder maxOutputTokens(Integer maxOutputTokens);
    public Builder stopSequences(List<String> stopSequences);
    public Builder frequencyPenalty(Double frequencyPenalty);
    public Builder presencePenalty(Double presencePenalty);

    // Bedrock-specific
    public Builder overrideWith(ChatRequestParameters parameters);
    public Builder additionalModelRequestFields(Map<String, Object> fields);
    public Builder additionalModelRequestField(String key, Object value);
    public Builder enableReasoning(Integer tokenBudget);
    public Builder promptCaching(BedrockCachePointPlacement placement);
    public Builder guardrailConfiguration(BedrockGuardrailConfiguration config);

    public BedrockChatRequestParameters build();
}

public class BedrockChatResponseMetadata extends ChatResponseMetadata {
    // Bedrock-specific
    public GuardrailAssessmentSummary guardrailAssessmentSummary();

    // Inherited
    public String id();
    public FinishReason finishReason();
    public TokenUsage tokenUsage();
    public String modelName();

    // Builder
    public Builder toBuilder();
    public static Builder builder();
}

public static class Builder extends ChatResponseMetadata.Builder<Builder> {
    // Inherited
    public Builder id(String id);
    public Builder finishReason(FinishReason finishReason);
    public Builder tokenUsage(TokenUsage tokenUsage);
    public Builder modelName(String modelName);

    // Bedrock-specific
    public Builder guardrailAssessmentSummary(GuardrailAssessmentSummary summary);

    public BedrockChatResponseMetadata build();
}

public class BedrockTokenUsage extends TokenUsage {
    public BedrockTokenUsage(Builder builder);

    // Inherited
    public Integer inputTokenCount();
    public Integer outputTokenCount();
    public Integer totalTokenCount();

    // Bedrock-specific cache metrics
    public Integer cacheWriteInputTokens();
    public Integer cacheReadInputTokens();

    // Operations
    public BedrockTokenUsage add(TokenUsage that);

    // Builder
    public static Builder builder();
}

public static class Builder {
    public Builder inputTokenCount(Integer inputTokenCount);
    public Builder outputTokenCount(Integer outputTokenCount);
    public Builder cacheWriteInputTokens(Integer cacheWriteInputTokens);
    public Builder cacheReadInputTokens(Integer cacheReadInputTokens);

    public BedrockTokenUsage build();
}