Heap: main-process OOM under heavy multi-agent orchestration — follow-up to #288 #327

Symptom

The Electron main process crashed with a hard V8 OOM during a long working session:

FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory

This is a follow-up to #288, not a regression of it. #288 dropped the steady-state main-process heap drastically (derive-and-drop in SubAgentWatcher, string interning, etc.), but a hard OOM crash means something is still growing unbounded — a stable-but-high heap can't CALL_AND_RETRY_LAST.

Two hypotheses

1. A secondary accumulator Main-process heap unbounded — full transcript + tool-output text retained in memory (681MB, 92% strings) #288 didn't cap. Main-process heap unbounded — full transcript + tool-output text retained in memory (681MB, 92% strings) #288 targeted SubAgentWatcher; a sibling structure (orchestration run-state, proxy flow state, history) may have the same unbounded-growth shape.
2. Heavy multi-agent orchestration specifically. The crash happened during a marathon orchestration session (many orchestration_create_agent children + reviewers). Each child's run-state, transcripts, and the orchestration MCP's retained run outputs all live in the main process, and several very large tool results were materialized there. The orchestration MCP (agent_code) disconnected/reconnected mid-session, consistent with it being the hog this time.

Diagnostic plan

• Restart the app; reproduce by running a heavy orchestration session (several children + reviewers) and watch RSS climb.
• Capture a main-process heap snapshot at high RSS; run scripts/analyze-heapsnapshot.mjs --owners <snap> to name the dominator (orchestration run-state vs. a new accumulator vs. SubAgentWatcher again).
• Check the unbounded disk-hog dirs that can also bleed into memory: ~/.config/agent-code/{feed-debug,debug-bundles,proxy,performance}.
• If orchestration is the cause: bound/evict retained child run outputs + transcripts in the main process (derive-and-drop, mirroring the Main-process heap unbounded — full transcript + tool-output text retained in memory (681MB, 92% strings) #288 fix).

Context

Surfaced while building the conditions-framework stack (integration/conditions-framework, PRs #325/#326) under heavy orchestrated review. Related: #288 (closed), #103 (perf sweep).