Tag each MCP request with which agent host is driving dws (agent_code) and a
per-(machine × agent_code) instance id, so usage can be sliced by channel and
instance in the data warehouse. Root cause it fixes: agent_code was only sent
when the host injected DINGTALK_DWS_AGENTCODE (~99.98% empty), so the gateway
logged none.
Detection ladder (every signature observed on a real host / official docs, not
guessed; unknown -> custom):
T0 explicit DINGTALK_DWS_AGENTCODE
T1 verified env signatures: claudecode (CLAUDECODE), codex (CODEX_SANDBOX),
openclaw (OPENCLAW_BUNDLE_ROOT), hermes (HERMES_HOME)
T2 VSCODE_BRAND value (covers the whole VS Code fork family)
T3 macOS __CFBundleIdentifier map (qoder/cursor/vscode/workbuddy)
T4 custom fallback
identity.json v2 (machineId + per-agent_code agents map), deterministic
dwsa_<base62> derivation, transparent v1 migration. Backward-compatible wiring:
x-dws-agent-id stays machine-level; new x-dws-agent-instance-id carries the
per-channel id; X-Cli-Version emitted so old/new clients are distinguishable.
Trust boundary (docs/agent-code.md): agent_code and the ids are self-reported
and spoofable — fit for statistics ONLY, never for auth/limit/billing.
Includes unit tests for every tier and the integration doc.
