Compatibility provenance

Official, normative sources used to design and verify public-wire compatibility are listed here. Non-official material, if deliberately consulted for independent internal design, is secondary and cannot establish a compatibility claim.

Official Go SDK (test dependency)

• github.com/anthropics/anthropic-sdk-go
• Test and reference version: v1.60.0, tag commit b43f0d7a327fe3e30c302d773162669ab3bb4d26 (verified 2026-07-24).
• Module checksum recorded in go.sum: h1:cZzHheifXy7+pps7XsQ/6hfVKc34gwNiG8butUzik/4=.
• Used only as a black-box compatibility client in tests (base URL pointed at an in-process httptest server through an explicit per-test client). No package-global SDK base-URL hook is used, and no SDK request/response types are copied into this repository. Successful decoding is evidence of interoperability, but it does not verify that every required response field is present.

Official documentation and API Reference

Verified 2026-07-29.

• API overview — auth headers, pagination, request-size limit, and error envelope.
• Claude API errors — Messages API status/error types, request IDs, transient retry classes, and Retry-After.
• Create Agent — model configuration, initial version, and response shape.
• Update Agent — optimistic concurrency and update-field semantics.
• Start a session — agent reference forms, initial events, and resolved snapshot.
• Create Session API Reference — full session response and resolved snapshot.
• Session operations — statuses, pagination, archive, and delete behavior.
• Events and streaming — event unions, content blocks, processing, and reconnect behavior.
• Events API Reference — requires_action.event_ids, the all-actions resolution boundary, and per-event processed_at semantics used by the durable pending-action gate.
• List Events API Reference — filters, pagination envelope, and per-event shapes.
• Multiagent orchestration — multiagent input shape and resolved-roster behavior.

Tool and sandbox sources

Verified 2026-07-28. These inform the tool-use loop, the built-in toolset declaration, the custom/permission handoff, and the tool-block event wire.

• Managed Agents tools — the agent_toolset_20260401 built-in toolset, per-tool enabled and permission_policy config, custom tools, and MCP toolsets.
• List Events and Send Events — the agent.tool_use / agent.tool_result / agent.custom_tool_use event variants and the user.custom_tool_result / user.tool_confirmation client events used for the handoff.
• Permission policies — always_allow / always_ask / always_deny evaluation and the requires_action stop reason that a pending confirmation produces.
• Cloud environment setup — reusable Environment configuration and isolated session sandbox ownership.
• Self-hosted sandboxes — the control-plane/worker boundary and session-scoped sandbox guidance.
• Bash tool and Text editor tool — consulted for public parameter conventions that shaped the internal input schemas we hand the model. These are Tool-Use (Messages API) conventions, not part of the Managed Agents public wire; the schemas we send are an internal design choice and are marked partial/internal in docs/compatibility.md.

The Anthropic Sandbox Runtime repository is referenced only as an experimental candidate backend. It does not establish Managed Agents API compatibility and no SRT integration is currently implemented.

Beta header for all Managed Agents routes covered here: anthropic-beta: managed-agents-2026-04-01.

Streaming sources

Verified 2026-07-26. These inform the opt-in shape and event correlation used by stream-only previews.

• Events and streaming — persisted event streaming, event-delta opt-in, and reconnect guidance.
• Streaming Messages — upstream Messages API SSE event types decoded by the real model client.

The inbound Messages API SSE wire and the outbound Managed Agents preview wire are separate contracts. The implementation translates between them rather than forwarding upstream frames.

Compatibility claim boundary

• The implemented tool set is bash, read, write, edit, glob, and grep. web_fetch, web_search, and MCP execution are not supported. The default local sandbox is a guardrail, not a security boundary; the optional Docker provider supplies container isolation.
• Opaque multiagent configuration persists with tested replace/null-clear behavior. Resolved rosters, reference validation, and multiagent execution/orchestration are not implemented.
• Unsupported product surfaces are excluded from compatibility claims until their wire behavior is implemented and tested.
• Only official documentation and official SDKs are normative for the public compatibility surface.