[bot] Bedrock Converse/ConverseStream requests: toolConfig (tool definitions) never captured in span metadata

[braintrust-bot]

Summary

InstrumentationSemConv.tagBedrockRequest() extracts inferenceConfig (maxTokens/temperature/topP/stopSequences), system, and messages from the Bedrock Converse/ConverseStream request body, but never reads the top-level toolConfig field. toolConfig carries the tool definitions and tool-choice policy sent to the model — a core, documented part of the Converse API request — and is silently dropped from every Bedrock LLM span's braintrust.metadata/braintrust.input_json, for both streaming and non-streaming calls.

This is a request-side gap and is distinct from issue #85 (which covers the response-side streaming reconstruction dropping tool-use content blocks in TeeingSubscriber/buildConverseJson). Even for non-streaming Converse calls where the response-side tool use is captured correctly by normalizeBedrockMessage(), the request never shows what tools were offered to the model or what tool-choice policy was set.

What is missing

In tagBedrockRequest() (InstrumentationSemConv.java, lines 339-396):

if (requestBody != null) {
 JsonNode requestJson = BraintrustJsonMapper.get().readTree(requestBody);
 if (requestJson.has("inferenceConfig")) { ... } // handled
 if (requestJson.has("messages")) { ... } // handled
}

There is no if (requestJson.has("toolConfig")) branch anywhere in this method. The Converse/ConverseStream request body's toolConfig object — containing tools (an array of toolSpec definitions with name/description/inputSchema) and toolChoice (auto/any/{tool: {name}}) — is read from requestBody but never surfaced into metadata or input_json. A trace of a tool-enabled Bedrock call shows the conversation and inference params but gives no visibility into which tools were available or how tool selection was constrained, even though the model's resulting stopReason: "tool_use" and tool call are otherwise correctly displayed.

Braintrust docs status

• Bedrock is listed as a supported provider at https://www.braintrust.dev/docs/integrations/ai-providers: supported
• No Bedrock-specific mention of tool/function-call request metadata capture on Braintrust docs: not_found

Upstream sources

• AWS Bedrock Converse API reference: https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_Converse.html — documents toolConfig as a top-level request field alongside messages, system, inferenceConfig
• AWS Bedrock ConverseStream API reference: https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_ConverseStream.html — same toolConfig request field
• AWS Bedrock tool use guide: https://docs.aws.amazon.com/bedrock/latest/userguide/tool-use.html — describes toolConfig.tools/toolConfig.toolChoice semantics

Local files inspected

• braintrust-sdk/src/main/java/dev/braintrust/instrumentation/InstrumentationSemConv.java — lines 339-396 (tagBedrockRequest: reads inferenceConfig, system, messages; no toolConfig handling anywhere in the method or file)
• braintrust-sdk/instrumentation/aws_bedrock_2_30_0/src/main/java/dev/braintrust/instrumentation/awsbedrock/v2_30_0/BraintrustBedrockInterceptor.java — passes the raw request body through to tagBedrockRequest; no separate toolConfig handling
• braintrust-sdk/instrumentation/aws_bedrock_2_30_0/src/test/java/dev/braintrust/instrumentation/awsbedrock/v2_30_0/BraintrustAWSBedrockTest.java — no test asserts on toolConfig appearing in captured metadata