[bot] Anthropic Managed Agents (beta.agents / beta.sessions) not instrumented in Java SDK

[braintrust-bot]

Summary

Anthropic's Managed Agents API (/v1/agents, /v1/environments, /v1/sessions, plus vaults/memory_stores) launched in public beta on 2026-04-08 and is officially supported by the Anthropic Java SDK (anthropic-sdk-java), which this repo's anthropic_2_2_0 module wraps. None of these endpoints are instrumented — only the standard Messages API (messages().create()) is traced.

Braintrust's own docs already document agents/sessions tracing for the sibling Python and TypeScript SDKs, but explicitly do not for Java, confirming this is a real, product-visible gap rather than an unsupported/deprecated surface.

What is missing

The Anthropic Java SDK exposes these beta service clients under client.beta.*, confirmed to exist in the current anthropic-sdk-java source tree (anthropic-java-core/src/main/kotlin/com/anthropic/services/blocking/beta/):

• AgentService / AgentServiceImpl (formerly agents.create()/agents.retrieve()/agents.list() — persisted, versioned agent configs: model, system prompt, tools, mcp_servers, skills)
• SessionService / SessionServiceImpl (sessions.create() — starts a session that streams agent-loop events back to the caller; requires an agent reference and environment_id)
• Sibling EnvironmentService, VaultService/CredentialService, MemoryStoreService under the same beta namespace

None of these are referenced anywhere in dev.braintrust.instrumentation.anthropic. The current instrumentation (TracingHttpClient in anthropic_2_2_0, dispatched through InstrumentationSemConv.tagAnthropicRequest/tagAnthropicResponse) only recognizes the standard /v1/messages request/response shape. Managed Agents endpoints use a different beta header (anthropic-beta: managed-agents-2026-04-01) and a different event-stream protocol (session turn events, user.message/user.define_outcome initial events), so a session's actual work — agent loop iterations, tool execution inside the sandbox, state transitions — produces no spans at all when driven through this SDK.

Braintrust docs status

Checked https://www.braintrust.dev/docs/integrations/ai-providers/anthropic directly:

• Python: documents tracing "the Anthropic SDK's messages, batches, and managed agents APIs," with an explicit span table row for anthropic.beta.agents.*, anthropic.beta.sessions.* → supported
• TypeScript: documents anthropic.beta.sessions.turn / anthropic.beta.sessions.thread.turn spans and a collectAnthropicSession helper to opt streamed session events into span collection → supported
• Java: the Java section only describes "Braintrust emits spans for the Anthropic Messages API" with a single span table row ("Anthropic Messages API spans" / messages().create(), including streaming) — no mention of agents, sessions, environments, or beta namespaces → not_found

Upstream sources

• Managed Agents overview: https://github.com/anthropics/skills/blob/main/skills/claude-api/shared/managed-agents-overview.md
• Managed Agents API reference: https://github.com/anthropics/skills/blob/main/skills/claude-api/shared/managed-agents-api-reference.md
• Official docs: https://platform.claude.com/docs/en/managed-agents/sessions
• Anthropic Java SDK beta service sources (confirmed present): https://github.com/anthropics/anthropic-sdk-java/tree/main/anthropic-java-core/src/main/kotlin/com/anthropic/services/blocking/beta (contains agents/, sessions/, environments/, vaults/, memorystores/ subdirectories with AgentService.kt, AgentServiceImpl.kt, SessionService.kt, SessionServiceImpl.kt)

Local files inspected

• braintrust-sdk/instrumentation/anthropic_2_2_0/src/main/java/dev/braintrust/instrumentation/anthropic/v2_2_0/ — no reference to agents, sessions, environments, beta, or managed-agents anywhere in the module
• braintrust-sdk/src/main/java/dev/braintrust/instrumentation/InstrumentationSemConv.java — tagAnthropicRequest/tagAnthropicResponse only handle the standard /v1/messages request/response JSON shape; no handling for session-turn event streams or agent/environment resource payloads
• Full-repo grep for beta.agents, beta.sessions, ManagedAgent, AgentService, SessionService — zero matches