Third profiling round (after #66033 / #66347), targeting the composer
model picker and dialog opens (worktree dialog etc.), measured over CDP
on real 1000+-message sessions.
Backend — model.options took 4.8s cold / 1.8s warm per call, and the
desktop model pill/picker blocks on it every open:
- agent/credential_pool: _load_config_safe uses load_config_readonly().
Every consumer only reads, and the per-call deepcopy was the dominant
cost — list_authenticated_providers calls load_pool() per provider
row, and each load_pool loaded (and deep-copied) the full config
again via get_pool_strategy.
- hermes_cli/config: memoize ensure_hermes_home() per home path. It
runs inside the config lock on EVERY load_config(), paying ~14
mkdir/chmod syscalls per call. The fast path still re-checks that the
home dir exists, so a deleted home is recreated as before; profile
switches hit the new path and re-run. Tests cover both.
- tui_gateway/server: add model.options to _LONG_HANDLERS. It measured
seconds inline on the WS reader thread — while it ran, prompt.submit
and session.interrupt sat unread (same class as #21123).
Together: model.options RPC 4825/1842ms → 426/230ms (measured on the
live desktop backend); build_models_payload in isolation 6.2s → 0.97s
cold, 0.27s warm.
Desktop — every Radix dialog/popover open forced a whole-document style
recalc (Presence reads getComputedStyle on mount), which on a
1300-message transcript cost ~650-730ms per open (CPU profile:
getAnimationName 483ms self). The worktree dialog (⌘⇧B) paid it on
every single open:
- thread/list: content-visibility:auto + contain-intrinsic-size on the
per-turn group wrappers. Off-screen turns now skip style recalc,
layout, and paint entirely; never-rendered turns hold a placeholder
height (auto: remembered real size once rendered) so scrollbar and
anchoring stay stable. Verified over CDP: worktree dialog open 656-
730ms → ~200ms on the same session; stick-to-bottom pin, scroll-to-
top rendering, and sticky human bubbles all intact.
Also: profile-session-switch harness accepts CDP_HTTP (Chrome tends to
squat on 9222).
Verification:
- scripts/run_tests.sh: config, credential-pool, inventory,
model-switch routing, tui_gateway protocol, profiles suites green
(test_profiles has one pre-existing failure on main, unrelated);
new tests for the ensure_hermes_home memo.
- apps/desktop: tsc clean, eslint/prettier clean, thread + session
suites green (326 tests).
- E2E over CDP on the live app: numbers above, plus scroll/pin sanity.
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