Two pathologies surfaced in the same captured failure (#2081): a subagent
spent 16 minutes hammering 205 `edit` calls (182 byte-identical no-ops)
against a file that already matched its payload, while a sibling bash
invocation persisted 7.6MB of PowerShell rich-object metadata to
`~/.omp/agent/artifacts/<id>.bash.log` from what was intended as a small
tail. Both are addressed independently here:
- Hashline executor now consults a per-ToolSession `noopLoopGuard` that
hashes the raw patch input and tracks consecutive no-ops per canonical
path. After NOOP_HARD_LIMIT (3) repeats of the same payload the soft
"byte-identical" hint escalates to a thrown ToolError, which the agent
loop surfaces as a tool failure rather than success-with-text — far
more effective at breaking the loop than the soft hint alone. A
non-noop commit (or any variant payload) resets the counter; state is
isolated per ToolSession so subagents cannot inherit each other's
history.
- OutputSink artifact-on-disk writes are now bounded by
`artifactMaxBytes` (default 4 MiB = 3 MiB head + 1 MiB rolling tail).
Once the head budget is exhausted, subsequent chunks divert into a
fixed-size tail ring; `dump()` replays the ring behind a single
`[ARTIFACT TRUNCATED: kept first … + last … of …; … elided from the
middle]` notice before closing the sink. Setting `artifactMaxBytes: 0`
restores the historical unbounded behavior. Sized comfortably above
anything a model would reasonably scroll through via the artifact URL
scheme while preventing the captured 7.6MB spray from sitting on disk.
The terminal-typing lag the reporter observed has multiple compounding
causes (transcript-render freezing is disabled on win32; the bash result
renderer lacks the per-render cache that the eval renderer already has).
Those land in a follow-up — the loop guard + artifact cap address the
root pathologies that turned the session into a multi-MB transcript in
the first place.
Fixes#2081
roboomp
77a68b1070