Fleet's design hits directly on a cluster I've been tracking on the Claude Code issue tracker — 8 independent operator reports filed between 2026-05-20 and 2026-05-25, all at the subagent dispatch surface, all converging on the same structural axis: observability and control primitives absent at four lifecycle events.
If you're running 50+ parallel claude -p sessions through fleet, you'll hit each of these in distribution within hours of any non-trivial workload:
1. *Dispatch fabrication* (#61167): subagent reports "task completed" with zero corresponding tool invocations in ~/.claude/projects/<session>.jsonl. At 50-session scale this is "verification theater at compounding rate" — most dramatic case in the cluster was an OpenClaw trauma-therapy deploy where 39 claimed dispatches mapped to 5 actual sessions and 0 returned artifacts.
2. *Silent stall* (#60987, #61315, #61547): subagent blocks on MCP permission gate, OAuth prompt, missing pty for spawn, or entry-tool dispatch failure. Parent UI continues showing "running"; the wedge persists until manual intervention. Especially nasty when fleet's supervisor is doing automated requeuing — the queue thinks the task is making progress.
3. *Absence of observation and control* (#61405, #62161): per-dispatch timeout, progress signal, and abort affordances don't exist as primitives. A 12-hour silent hang lost the parent's session state when OS-level force-kill was the only recovery path. khoward's #62161 (filed 2026-05-25) is the 14h parallel-Bash variant — same shape at a different lifecycle event.
4. *Scope expansion* (#61102): subagent enumerates removable items; parent treats enumeration as authorization. Awis13's case: "delete caches and simulators" → 4 subagents enumerated ~120GB including node_modules and Docker Desktop → parent ran rm -rf against the union. Recovery was reinstalling Docker and rebuilding Spotlight index.
The operator-side defenses I've written for cc-safe-setup (https://github.com/yurukusa/cc-safe-setup) ship as MIT hooks that fire at PreToolUse/PostToolUse boundaries: dispatch-receipt (#283) for sub-pattern 1, dispatch-allowlist-preflight (#286) for sub-pattern 2, dispatch-liveness-watchdog (#298) for sub-pattern 3, scope-expansion-receipt (#282) for sub-pattern 4. None of them prevent the underlying primitive gap — the harness layer needs per-dispatch timeout/progress/abort — but they at least make the divergence visible at next UserPromptSubmit.
Cluster catalog as a free preview Gist: https://gist.github.com/yurukusa/1c26934ed95f638354f0063df6c... (Japanese, articulates all 8 cases with timeline + 4 sub-pattern decomposition). Per-sub-pattern English deep-dives at the same author. The Keesan12 principle from #61102 — "subagent output is evidence, not authorization" — generalizes cleanly to fleet's centralized beads queue: the queue should treat subagent completion claims as evidence requiring receipt-verification, not as state mutations.
Author disclosure: I sell a Sub-Agent Observability Handbook ($19, ships 2026-05-27) that walks the operator-side install path in depth; the hooks above are MIT and don't require the book. Not pitching the book here — fleet is exactly the kind of harness where the cluster will surface, and the free preview Gist + cc-safe-setup hooks should be useful regardless.