build_stream_config

Build the LangGraph stream config dict.

Stamps the shared coding-agent-v1 trace-metadata contract via build_coding_agent_metadata — identity block, plugin/runtime versions, turn markers, and repo/git/cwd attribution — onto metadata. Metadata set here propagates trace-wide to every run in the graph (root, llm, tool, and subagent subgraphs), which is exactly what the contract's "always" and "where-known" keys require, so the helper output is stamped once here.

Scope-restricted contract keys are deliberately not emitted. approval_policy (root/interrupted only) and ls_subagent_id / ls_subagent_type (subagent only) cannot live in this trace-wide metadata: LangGraph propagates each key to all descendant runs (per-key config merge, langgraph#7926 / deepagents#3634), so they would leak onto run types outside their contract appliesTo set and fail validation. This runtime exposes no clean per-run-type metadata seam to scope them, so they are omitted by design rather than leaked. (Subagent runs still inherit the parent/root thread_id and all required keys, satisfying the contract's grouping rule.)

Also injects the dcode version into metadata["lc_versions"] so LangSmith traces can be correlated with specific releases. create_deep_agent supplies the SDK version through the compiled graph config, and LangChain merges nested metadata dictionaries so both versions survive at stream time.

Also records dcode_client_deepagents_version as a dcode-client diagnostic. This describes the Deep Agents package installed alongside the TUI, which can differ from a remote graph's Deep Agents runtime version. Editable installs carry an +editable suffix, matching how the SDK stamps lc_versions["deepagents"]; for sibling monorepo packages that suffix identifies workspace HEAD relative to the pinned published SDK baseline.

Also records dcode_experimental=True when DEEPAGENTS_CODE_EXPERIMENTAL is enabled, so experimental runs are filterable in trace metadata.

Also records dcode_auto_approve=True when auto-approve ("YOLO") mode is active, so runs that ran tools without HITL approval are filterable in trace metadata. This is a diagnostic key, not the contract-scoped approval_policy key (see above), so it is safe to stamp trace-wide.

Also records dcode_term_program from TERM_PROGRAM when that is non-empty after stripping, so traces are groupable by launch environment (e.g. "iTerm.app", "vscode", "Apple_Terminal"). Blank values are treated as unset to match every other reader of this variable — some shells export TERM_PROGRAM="" rather than leaving it unset, and terminals that never set it (Windows Terminal, ssh, the Linux console) omit the key entirely rather than forming a junk grouping bucket. This is a diagnostic key, not part of the contract.