A TUI run against an unreachable endpoint failed with only 'fetch failed':
undici wraps transport failures in a bare TypeError whose diagnosis lives
on .cause, and every diagnostic seam rendered only error.message. The
readline front door additionally rendered failed turns as pure silence.
- dsh-llm: new errorChain(value) renders the full cause chain and
AggregateError members with circular/hostile-coercion containment.
- llm-deepseek: pre-response transport failures throw LlmError('NETWORK')
naming the endpoint and chaining the fetch TypeError; aborts keep their
DOMException so the loop still classifies them as cancellation.
- agent-loop: durable turn/end error messages and logger warnings render
through errorChain; local renderThrown copies removed.
- ui-stdio: failure turn/end reasons now render ([turn failed <code>],
[turn aborted], [turn rejected], output-token-limit); startup-failure
logs use errorChain.
- ui-tui: agent/error notices and the startup-failure line use errorChain.
Master unifies every live agent with its exact SessionId and moves declarative startup failures to agent-loop/config-start-failed. Keeping the branch’s AgentId label binding would let the TUI target the wrong lifecycle after reload and would miss asynchronous resume failures.
Resolve that contract migration by giving the selected terminal front door the same generated or resumed SessionId as agent-core, mounting the front door first, and entering fullscreen only after the matching root appears. Refresh the source-derived catalogs and keyless terminal goldens so Code Mode, workflow, Cordis-tool, and transient UI scenarios all exercise the merged identity model.
