diff --git a/.agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.i18n.yaml b/.agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.i18n.yaml
index 29bb8f7251..e4f53866bf 100644
--- a/.agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.i18n.yaml
+++ b/.agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write .agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.md
-2026-07-31-code-runtime-python-settlement-fixes.md: 1a55169bc27f1add06689d4a5582fd6e843bc354
-2026-07-31-code-runtime-python-settlement-fixes.zh.md: d567ce58864479ee92388374f0ec6125614d7d71
+2026-07-31-code-runtime-python-settlement-fixes.md: 4ab813d0b87f144d2a89c73e65f2579899a07acc
+2026-07-31-code-runtime-python-settlement-fixes.zh.md: 346e91dab39ec0268707c696416d66bea839291b
diff --git a/.agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.md b/.agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.md
index 1a55169bc2..4ab813d0b8 100644
--- a/.agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.md
+++ b/.agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.md
@@ -6,7 +6,7 @@ English | [中文](2026-07-31-code-runtime-python-settlement-fixes.zh.md)
 
 ## Problem
 
-The CPython subprocess backend for Code Mode, built on the [fd-3 frame protocol](../architecture/2026-07-31-code-runtime-python-fd3-protocol.md), resolves every program outcome as a `CodeRunResult`, rejects `run()` only for seam misuse, and disposes to quiescence so no subprocess that stays in the child's process group outlives the fiber (a descendant that escapes the group with `setsid()` is the documented exception — see the package README's Known Limitations). A sequence of review passes surfaced defects that broke those contracts in ways unit coverage did not catch — each hid behind a `/* v8 ignore */`, a captured-callable that read as a fix but was not, a memory effect invisible through the seam, a load-time bound that double-counted, a process-group escalation that a survivor could outlast, a cross-event-loop completion that silently deadlocked, a synchronous throw outside the settlement path, or a transport boundary rendered as a log boundary. Most behavioral fixes ship with a test that fails without them; six do not, and are called out as such — the chunked frame read (a syscall-count improvement with no cross-platform-deterministic failure), the confirmed-empty finalize (its only seam-observable effect, a frozen heartbeat, freezes the instant SIGKILL is delivered, which the pre-fix finalize-on-delivery code also produced, and the discriminating probe is the signal-0 check the Alternatives reject as cross-environment-unreliable), the shared stdout/stderr budget (its only seam-observable difference is which entry boundary a mid-stream flush lands on, and that depends on the relative arrival timing of two independent OS pipes, which `os.sched_yield` does not make deterministic; the per-pipe memory bounds it strengthens ARE covered by the single-pipe flood tests), the `flush_line` join-clear-push reorder (it lowers the settlement-flush peak from three copies to two, but the 12x load gate already covers the three-copy newline path, so every gate-admitted config stays within the address space under both orders and no seam-observable difference exists — the memory effect is inside the Python child, unmeasurable through the seam like the shared-budget case), pacing binding replies (its in-tree case only asserts the framed replies still round-trip; the peak it removes lives inside the host's fd-3 writable buffer, unseen through the seam, so the 32.0 MiB → 0.0 MiB reduction is measurable only out-of-tree), and dropping a late binding resolution before snapshot (its three assertions all also hold pre-fix, because `sendReply` already dropped after-settlement values — just later than the snapshot).
+The CPython subprocess backend for Code Mode, built on the [fd-3 frame protocol](../architecture/2026-07-31-code-runtime-python-fd3-protocol.md), resolves every program outcome as a `CodeRunResult`, rejects `run()` only for seam misuse, and disposes to quiescence so no subprocess that stays in the child's process group outlives the fiber (a descendant that escapes the group with `setsid()` is the documented exception — see the package README's Known Limitations). A sequence of review passes surfaced defects that broke those contracts in ways unit coverage did not catch — each hid behind a `/* v8 ignore */`, a captured-callable that read as a fix but was not, a memory effect invisible through the seam, a load-time bound that double-counted, a process-group escalation that a survivor could outlast, a cross-event-loop completion that silently deadlocked, a synchronous throw outside the settlement path, or a transport boundary rendered as a log boundary. Most behavioral fixes ship with a test that fails without them; nine do not, and are called out as such — the chunked frame read (a syscall-count improvement with no cross-platform-deterministic failure), the confirmed-empty finalize (its only seam-observable effect, a frozen heartbeat, freezes the instant SIGKILL is delivered, which the pre-fix finalize-on-delivery code also produced, and the discriminating probe is the signal-0 check the Alternatives reject as cross-environment-unreliable), the shared stdout/stderr budget (its only seam-observable difference is which entry boundary a mid-stream flush lands on, and that depends on the relative arrival timing of two independent OS pipes, which `os.sched_yield` does not make deterministic; the per-pipe memory bounds it strengthens ARE covered by the single-pipe flood tests), the `flush_line` join-clear-push reorder (it lowers the settlement-flush peak from three copies to two, but the 12x load gate already covers the three-copy newline path, so every gate-admitted config stays within the address space under both orders and no seam-observable difference exists — the memory effect is inside the Python child, unmeasurable through the seam like the shared-budget case), pacing binding replies (its in-tree case only asserts the framed replies still round-trip; the peak it removes lives inside the host's fd-3 writable buffer, unseen through the seam, so the 32.0 MiB → 0.0 MiB reduction is measurable only out-of-tree), dropping a late binding resolution before snapshot (its three assertions all also hold pre-fix, because `sendReply` already dropped after-settlement values — just later than the snapshot), the done-value TOCTOU pre-encoding (a concurrent mutation racing the encode cannot be deterministically constructed through the seam — its daemon-mutation regression only asserts the result is never a `worker-exit`, which is probabilistic and non-discriminating, so under the existing no-fail-before-with-a-reason precedent it is registered as no-fail-before), the stray-UTF-8 budget-flush retention (a budget flush landing exactly on a multibyte boundary is not schedulable through the seam; it is cross-referenced as v8-ignored), and the late-rejection settled guard (a rejection arriving after the run has already settled cannot be deterministically constructed from the seam).
 
 ## Decision
 
@@ -72,11 +72,25 @@ The host gate validates against the CONFIGURED `addressSpaceMb`, but a launch en
 
 One residual write-path copy is fixed alongside, independent of the config gate: `_LogStream.write`'s newline branch buffered the whole unterminated tail after the last newline (`text[pos:]`) into `_pending` before the flush trigger could bound it, so an early newline followed by a huge tail (`"\n" + "A" * 30 MiB`) made a second full copy of the model's own string — the `RLIMIT_AS` death the path exists to avoid, and one the config gate does not cover because the tail can far exceed `maxLogBytes`. The tail is now sliced to a `remaining + 4`-character prefix (anything past `remaining` characters cannot be admitted, the char count being a lower bound on the serialized cost), which the flush trigger then rejects with the marker.
 
+### The completion value and error are pre-encoded at their validation point
+
+In [`py/bootstrap.py`](../../../../packages/code-runtime/code-runtime-python/py/bootstrap.py), `_done_with_value` now returns the whole terminal frame as a PRE-ENCODED JSON string on the success path: the admitted value is serialized once here, at the validation point inside `_run`'s `try`, as `'{"type": "done", "value": ' + _encode_json_plain(value) + "}"`. The program can keep mutating a returned list/dict from a daemon thread or signal handler after it returns, so a second traversal held at a later point would be a TOCTOU — a concurrent mutation into a non-JSON type would let that later encode throw outside the settlement handler and downgrade a settled run host-side to `worker-exit`. Serializing once, inside the `try` that wraps this call, closes the window: if a concurrent mutation makes the encode throw, the exception handler classifies it as an `exception`, and once the string is produced the frame is written verbatim with no further touching of the live value.
+
+`send_done` (a local function inside `_run`) writes the pre-encoded string through a BOUND `channel.write_encoded`, and encodes a dict error frame through a bound `_encode_json_plain` before writing it — it never calls `channel.send_sync`, whose body re-resolves `self.write_encoded` and the module-level `_encode_json_plain` at call time. `_encode_json_plain` and `channel.write_encoded` are bound into locals before the program runs, for the same reason `flush_out`/`flush_err`/`safe_model_traceback` are: the program runs as `__main__`, so `import __main__; __main__.ProtocolChannel.send_sync = boom` or `__main__._encode_json_plain = boom` would otherwise re-resolve the send/encode to a rebranded callable at call time and, when that replacement raises, skip the `done` frame and downgrade a settled verdict to a host-side `worker-exit`.
+
+### A budget flush retains an unfinished trailing multibyte sequence
+
+Also in [`src/index.ts`](../../../../packages/code-runtime/code-runtime-python/src/index.ts), `flushStray(stray, retainPartialTail)` withholds an unfinished multibyte tail from the decode on the BUDGET-triggered flush (the combined-cost threshold in `captureStray`): when the residual ends on a partial UTF-8 lead sequence (`stray.utf8.expected > 0`), the leading byte plus the continuations consumed so far (≤3 bytes) are detached from the frame as the new residual, and only the complete prefix is admitted and decoded. Nothing is admitted when the whole residual is a single unfinished sequence, so a legal, un-finished character is never rendered as U+FFFD in a released, un-truncated entry, and no bogus empty entry is pushed. The withheld tail is re-accrued from a FRESH `stray.utf8` state — metering it against the post-flush `expected > 0` state would charge the carried lead byte as an illegal continuation — so the next chunk continues the walk correctly and the pipe's cost/UTF-8 state is rebuilt over the retained tail. The `end`/`closeDeadline` paths pass `false` and decode the FULL residual unchanged, because there a trailing incomplete sequence is real truncated input and the U+FFFD is the honest render.
+
+### A late binding rejection returns before formatting the error
+
+Also in `src/index.ts`, the binding-rejection catch branch now checks `settled` and returns BEFORE formatting `messageOf(error)`. A rejection that arrives after `maxWallMs`, an abort, or dispose has already settled the run would otherwise have `messageOf(error)` run hostile `toString`/`message` getters — spending host heap and time on a run whose outcome is already fixed — before `sendReply` peeks at `settled`. Dropping the framed reply early spares that waste. The running loop's otherwise-mostly-linear reply drain also reads by a head cursor into the queue array instead of `shift()`ing each entry, so a large `asyncio.gather` of wide bindings awaiting fd 3's `drain` drains in linear time rather than O(n²) from repeated re-slicing.
+
 ## Testing
 
 - `tests/boot-write-failure.spec.ts` mocks `spawn` so the fd-3 pipe throws on the boot write — the one path a real subprocess cannot be coerced into — and asserts `run()` resolves a `worker-exit` rather than rejecting. A sibling case makes the mocked `spawn` throw SYNCHRONOUSLY and asserts `run()` still resolves a `worker-exit` and removes its staging directory, keyed off the exact bootstrap path the mocked `spawn` received in its argv so a sibling worker's concurrent staging cannot flake it. Both are isolated in this spec so the real-subprocess suite is untouched.
 - `tests/residual-detach.spec.ts` unit-tests `detachResidual`: the carried copy equals the residual, owns a backing store sized to its own length (fixture kept above Node's Buffer pool threshold), and does not share the source frame's `ArrayBuffer`.
-- `tests/runtime.spec.ts` — the output-cap case asserts the `ceiling - envelope` bound (268435392) and its message. A daemon-thread case drives four threads emitting unterminated writes through settlement's flush. A native-write case writes 200 KiB with no newline via `os.write` under a raised `maxLogBytes` and asserts it reads back as EXACTLY one log entry (proving stray output is aggregated by line, not split at pipe-chunk boundaries); a companion writes `b"one\ntwo\nthree"` and asserts three entries (proving real newlines still delimit). A newline-free-flood case writes 2 MiB under a 4 KiB `maxLogBytes` and asserts the capture ends at the truncation marker and stays under budget (proving the residual is bounded by the ledger, not buffered whole); a NUL-flood companion writes 4000 newline-free NULs under the same budget and asserts truncation (proving the residual is charged by SERIALIZED cost, ~6× raw, measured without allocating the escaped copy); an illegal-UTF-8 case paces single-byte `\xff` writes under a 3072-byte budget with `Buffer.concat` wrapped to measure the peak merged buffer, asserting it stays under 2048 (charged at the U+FFFD width 3 the residual flushes near 1024 raw bytes; a raw-byte undercount would let it reach ~3072, so the bound discriminates); a CESU-8/overlong case paces the structurally-well-formed but illegal `ED A0 80` one byte at a time and asserts the same peak bound (charged at the true 9 per sequence it flushes early; charging the structural width 3 triples the peak, so reverting the per-lead range check turns it red); a broken-multibyte case writes a 3-byte lead then a fresh ASCII byte in separate chunks and asserts both a captured `A` and a U+FFFD (exercising `accrueStrayCost`'s cross-chunk broken-sequence branch); a post-truncation case writes a 108-byte payload (under the smallest PIPE_BUF, so one atomic write) whose first line exhausts a 64-byte budget and asserts the second line is dropped (exercising the post-truncation admit no-op in one `data` callback, no v8-ignore); a short-escape case writes a line mixing a tab, quote, backslash, a `\uXXXX` control, a multibyte character, and ASCII, asserting it round-trips verbatim (exercising every branch of `jsonStringCostUpTo`); a reassembly case writes a payload spanning every valid multibyte lead class (E0-range, plain 3-byte, F0, and F4) past the pipe buffer and asserts it round-trips with no U+FFFD (exercising `accrueStrayCost`'s per-lead ranges and cross-chunk reassembly); a lone-surrogate case forges an fd-3 `log` frame flooding 1000 `\ud800` escapes under a 4 KiB budget and asserts truncation (the count sits in the window where charging 3 bytes would admit and 6 bytes truncates, proving the surrogate is charged its full escaped width); a stray-sealing case paces 60000 single-byte newline-free `os.write(1, …)` calls under a raised budget with `Buffer.concat` wrapped to measure copy volume, asserting the trickle coalesces to one entry and the cumulative copy stays under a measured 256 KiB threshold (the sealed shape copies ~120 KB, the re-merge shape ~538 KB, so reverting the seal to a re-merge turns the assertion red — proving the fragment list seals into blocks past `MAX_PENDING_CHUNKS`). A closeDeadline-flush case has the leader write a newline-free diagnostic then spawn a `setsid` orphan holding the pipes open, and asserts the diagnostic survives in `logs` (proving the residual is flushed before the deadline destroys the streams). The same-group reap case spawns a SIGTERM-ignoring same-group descendant that releases the pipes and bumps a heartbeat file; the test asserts the heartbeat STOPS after the grace-window SIGKILL — an assertion robust whether the killed descendant is reaped or lingers as a zombie, so it holds where PID 1 does not wait() orphans. A dispose-after-resolve case asserts `dispose()` of a completed run with a same-group survivor returns only after the survivor stops executing (proving the run stays in `live` until its group is reaped), with an `expect(afterDispose).toBeGreaterThan(0)` guard so the frozen-heartbeat assertion cannot pass vacuously when the file was never written. A deadline case busy-blocks the event loop past both timers and asserts the survivor's heartbeat freezes (proving the poll's deadline arm sends SIGKILL itself rather than cancelling the unfired escalation). The cross-loop case runs a binding from a worker thread's own `asyncio.run` loop while the main coroutine yields with `await asyncio.sleep`, asserting the reply round-trips instead of timing out; a companion case abandons a thread's call so its loop closes, then answers it before a later binding — asserting the pump survives the closed-loop `call_soon_threadsafe` (host-gated ordering makes it deterministic, fail-before hangs the later binding to the wall clock). The inherited-soft-limit case runs the interpreter through a `ulimit -S -t` wrapper that sets a CPU soft limit below `cpuSeconds` and asserts the applied `RLIMIT_CPU` soft is the inherited value, not the configured one (CPU rather than address space, since macOS ignores `ulimit -v`); a companion inherits a 1 s CPU soft, has the program trap SIGXCPU and busy-loop past it, and asserts the settlement recheck reports a timeout — proving the recheck uses the effective soft, not the configured `cpuSeconds`. A control-heavy-diagnostic case raises a NUL-flood exception under a small `maxValueBytes` and asserts the serialized frame fits (proving the diagnostic is metered by serialized cost). A tail-copy case (`maxLogBytes: 256`, `addressSpaceMb: 384`) has the program build a tail in a variable and write `"\n" + tail` where `tail` is 150 MiB — construction peaks at ~2× (~300 MiB, within the address space, so the model's own allocation succeeds and any OOM belongs to the defect path), and the pre-fix whole-tail re-buffer added a third ~150 MiB copy past 384 MiB; the sliced prefix lets the run truncate and complete (Linux-only RLIMIT_AS repro, macOS happy path — the fixture's own construction must fit the address space, a general rule for these RLIMIT_AS cases). An output-budget/address-space case asserts a `maxLogBytes` of 50 MB AND a `maxValueBytes` of 50 MB each reject at load against a 256 MiB `addressSpaceMb` (past the room left after the interpreter baseline when multiplied by the worst-case 12) while the default caps against 512 MiB load, gating both budgets symmetrically; a discriminating case asserts a 48 MiB `maxLogBytes` against a 512 MiB `addressSpaceMb` rejects — 48×8 = 384 MiB fits the 448 MiB budgetable (the old 8× multiple wrongly admitted it) but 48×12 = 576 MiB does not. The ~12× peak the multiple covers is the NEWLINE path's single near-budget write — the caller's own string, the line slice, and the encode copy live at once; the settlement flush is no longer the binding case, because `flush_line` drops the pending chunks before its push and so holds two copies rather than three. An inherited-RLIMIT_AS case runs the interpreter through a `ulimit -v 131072` wrapper with a 32 MiB `maxLogBytes` the configured 512 MiB `addressSpaceMb` admits, and asserts the boot re-check rejects it as an `exception` whose message names the inherited RLIMIT_AS (the 128 MiB inherited limit leaves too little after the baseline; Linux-only, macOS ignores `ulimit -v` and the run proceeds). A non-integer-budget case asserts a fractional `maxLogBytes`/`maxValueBytes` rejects at load. A combined-peak case (`maxLogBytes: 32 MiB`, `maxValueBytes: 32 MiB`, `addressSpaceMb: 512` — each budget admitted alone at 12×) writes ~33M newline-free astral characters (buffered, unflushed) then returns ~33M astral characters, and asserts the run settles as `output-limit` (the value is itself over its 32 MiB budget); pre-fix the unflushed log pending plus the value's build-and-encode peak added past the 512 MiB address space and OOM'd, so flushing the logs before framing the value is what lets the value check complete (Linux-only RLIMIT_AS repro; on macOS the over-budget value reports output-limit under both orders). A wide-value case (`maxValueBytes: 20 MiB`, `addressSpaceMb: 384`) returns `[0] * 6_000_000` — ~12 MB of JSON, under the 20 MiB budget, so it must round-trip; pre-fix the O(width) walk allocated ~400 MB of per-element traversal tuples and encoder stack entries (~28× the serialized size, past the 12× the gate reserves) and OOM'd on a value the meter admitted, while the O(depth) cursor keeps the only width-proportional allocation the output string itself (Linux-only RLIMIT_AS repro; the fixture stays within the address space so it is honest on macOS too). A wide-BINDING-ARGUMENT case (`addressSpaceMb: 384`) calls a binding with `[0] * 6_000_000` and asserts the length echoes back: `_lossless_json_violation` runs on model-built arguments that no child-side budget bounds first, and its per-member tuples measured 459.1 MiB against 0.0 MiB for the cursor. A backtracking case returns a 4 MiB string from a binding and asserts it round-trips: the old scalar regex retained engine state proportional to the string's width (146 MiB at 1 MiB, 557.8 MiB at 4 MiB, past the default 512 MiB), which raised MemoryError inside `_pump_replies` and stranded the call to the wall clock. A control-heavy metering case returns 8M NULs under a 16 MiB `maxValueBytes` and asserts `output-limit`, not `exception`: charging by counting instead of materializing the escaped form measured 19.1 MiB against 228.9 MiB for an identical byte count. An addressSpaceMb-baseline case asserts 64 MiB and 32 MiB reject at load with a message naming `addressSpaceMb`, rather than the budget loop's negative admissible limit. A process-identity case asserts the leader's start time reads stably on Linux and reports undefined on Darwin, the guard that keeps a recycled pgid from receiving this run's SIGTERM. A paced-replies case resolves eight 4 MiB values in one `asyncio.gather` round and asserts the frames round-trip; the peak the fix removes (32.0 MiB buffered → 0.0 MiB) lives in the host's fd-3 writable buffer, invisible through the seam, so this case pins the round-trip and the no-regression match but is measured for its peak only out-of-tree. A late-drop case settles the run on `maxWallMs` and resolves the pending binding afterwards, asserting a `timeout` result, an undefined value, and that the late path actually ran — the three assertions all hold pre-fix because `sendReply` already dropped after-settlement values, just later, so the case pins the ordering, not a seam-observable behavior.
+- `tests/runtime.spec.ts` — the output-cap case asserts the `ceiling - envelope` bound (268435392) and its message. A daemon-thread case drives four threads emitting unterminated writes through settlement's flush. A native-write case writes 200 KiB with no newline via `os.write` under a raised `maxLogBytes` and asserts it reads back as EXACTLY one log entry (proving stray output is aggregated by line, not split at pipe-chunk boundaries); a companion writes `b"one\ntwo\nthree"` and asserts three entries (proving real newlines still delimit). A newline-free-flood case writes 2 MiB under a 4 KiB `maxLogBytes` and asserts the capture ends at the truncation marker and stays under budget (proving the residual is bounded by the ledger, not buffered whole); a NUL-flood companion writes 4000 newline-free NULs under the same budget and asserts truncation (proving the residual is charged by SERIALIZED cost, ~6× raw, measured without allocating the escaped copy); an illegal-UTF-8 case paces single-byte `\xff` writes under a 3072-byte budget with `Buffer.concat` wrapped to measure the peak merged buffer, asserting it stays under 2048 (charged at the U+FFFD width 3 the residual flushes near 1024 raw bytes; a raw-byte undercount would let it reach ~3072, so the bound discriminates); a CESU-8/overlong case paces the structurally-well-formed but illegal `ED A0 80` one byte at a time and asserts the same peak bound (charged at the true 9 per sequence it flushes early; charging the structural width 3 triples the peak, so reverting the per-lead range check turns it red); a broken-multibyte case writes a 3-byte lead then a fresh ASCII byte in separate chunks and asserts both a captured `A` and a U+FFFD (exercising `accrueStrayCost`'s cross-chunk broken-sequence branch); a post-truncation case writes a 108-byte payload (under the smallest PIPE_BUF, so one atomic write) whose first line exhausts a 64-byte budget and asserts the second line is dropped (exercising the post-truncation admit no-op in one `data` callback, no v8-ignore); a short-escape case writes a line mixing a tab, quote, backslash, a `\uXXXX` control, a multibyte character, and ASCII, asserting it round-trips verbatim (exercising every branch of `jsonStringCostUpTo`); a reassembly case writes a payload spanning every valid multibyte lead class (E0-range, plain 3-byte, F0, and F4) past the pipe buffer and asserts it round-trips with no U+FFFD (exercising `accrueStrayCost`'s per-lead ranges and cross-chunk reassembly); a lone-surrogate case forges an fd-3 `log` frame flooding 1000 `\ud800` escapes under a 4 KiB budget and asserts truncation (the count sits in the window where charging 3 bytes would admit and 6 bytes truncates, proving the surrogate is charged its full escaped width); a stray-sealing case paces 60000 single-byte newline-free `os.write(1, …)` calls under a raised budget with `Buffer.concat` wrapped to measure copy volume, asserting the trickle coalesces to one entry and the cumulative copy stays under a measured 256 KiB threshold (the sealed shape copies ~120 KB, the re-merge shape ~538 KB, so reverting the seal to a re-merge turns the assertion red — proving the fragment list seals into blocks past `MAX_PENDING_CHUNKS`). A closeDeadline-flush case has the leader write a newline-free diagnostic then spawn a `setsid` orphan holding the pipes open, and asserts the diagnostic survives in `logs` (proving the residual is flushed before the deadline destroys the streams). The same-group reap case spawns a SIGTERM-ignoring same-group descendant that releases the pipes and bumps a heartbeat file; the test asserts the heartbeat STOPS after the grace-window SIGKILL — an assertion robust whether the killed descendant is reaped or lingers as a zombie, so it holds where PID 1 does not wait() orphans. A dispose-after-resolve case asserts `dispose()` of a completed run with a same-group survivor returns only after the survivor stops executing (proving the run stays in `live` until its group is reaped), with an `expect(afterDispose).toBeGreaterThan(0)` guard so the frozen-heartbeat assertion cannot pass vacuously when the file was never written. A deadline case busy-blocks the event loop past both timers and asserts the survivor's heartbeat freezes (proving the poll's deadline arm sends SIGKILL itself rather than cancelling the unfired escalation). The cross-loop case runs a binding from a worker thread's own `asyncio.run` loop while the main coroutine yields with `await asyncio.sleep`, asserting the reply round-trips instead of timing out; a companion case abandons a thread's call so its loop closes, then answers it before a later binding — asserting the pump survives the closed-loop `call_soon_threadsafe` (host-gated ordering makes it deterministic, fail-before hangs the later binding to the wall clock). The inherited-soft-limit case runs the interpreter through a `ulimit -S -t` wrapper that sets a CPU soft limit below `cpuSeconds` and asserts the applied `RLIMIT_CPU` soft is the inherited value, not the configured one (CPU rather than address space, since macOS ignores `ulimit -v`); a companion inherits a 1 s CPU soft, has the program trap SIGXCPU and busy-loop past it, and asserts the settlement recheck reports a timeout — proving the recheck uses the effective soft, not the configured `cpuSeconds`. A control-heavy-diagnostic case raises a NUL-flood exception under a small `maxValueBytes` and asserts the serialized frame fits (proving the diagnostic is metered by serialized cost). A tail-copy case (`maxLogBytes: 256`, `addressSpaceMb: 384`) has the program build a tail in a variable and write `"\n" + tail` where `tail` is 150 MiB — construction peaks at ~2× (~300 MiB, within the address space, so the model's own allocation succeeds and any OOM belongs to the defect path), and the pre-fix whole-tail re-buffer added a third ~150 MiB copy past 384 MiB; the sliced prefix lets the run truncate and complete (Linux-only RLIMIT_AS repro, macOS happy path — the fixture's own construction must fit the address space, a general rule for these RLIMIT_AS cases). An output-budget/address-space case asserts a `maxLogBytes` of 50 MB AND a `maxValueBytes` of 50 MB each reject at load against a 256 MiB `addressSpaceMb` (past the room left after the interpreter baseline when multiplied by the worst-case 12) while the default caps against 512 MiB load, gating both budgets symmetrically; a discriminating case asserts a 48 MiB `maxLogBytes` against a 512 MiB `addressSpaceMb` rejects — 48×8 = 384 MiB fits the 448 MiB budgetable (the old 8× multiple wrongly admitted it) but 48×12 = 576 MiB does not. The ~12× peak the multiple covers is the NEWLINE path's single near-budget write — the caller's own string, the line slice, and the encode copy live at once; the settlement flush is no longer the binding case, because `flush_line` drops the pending chunks before its push and so holds two copies rather than three. An inherited-RLIMIT_AS case runs the interpreter through a `ulimit -v 131072` wrapper with a 32 MiB `maxLogBytes` the configured 512 MiB `addressSpaceMb` admits, and asserts the boot re-check rejects it as an `exception` whose message names the inherited RLIMIT_AS (the 128 MiB inherited limit leaves too little after the baseline; Linux-only, macOS ignores `ulimit -v` and the run proceeds). A non-integer-budget case asserts a fractional `maxLogBytes`/`maxValueBytes` rejects at load. A combined-peak case (`maxLogBytes: 32 MiB`, `maxValueBytes: 32 MiB`, `addressSpaceMb: 512` — each budget admitted alone at 12×) writes ~33M newline-free astral characters (buffered, unflushed) then returns ~33M astral characters, and asserts the run settles as `output-limit` (the value is itself over its 32 MiB budget); pre-fix the unflushed log pending plus the value's build-and-encode peak added past the 512 MiB address space and OOM'd, so flushing the logs before framing the value is what lets the value check complete (Linux-only RLIMIT_AS repro; on macOS the over-budget value reports output-limit under both orders). A wide-value case (`maxValueBytes: 20 MiB`, `addressSpaceMb: 384`) returns `[0] * 6_000_000` — ~12 MB of JSON, under the 20 MiB budget, so it must round-trip; pre-fix the O(width) walk allocated ~400 MB of per-element traversal tuples and encoder stack entries (~28× the serialized size, past the 12× the gate reserves) and OOM'd on a value the meter admitted, while the O(depth) cursor keeps the only width-proportional allocation the output string itself (Linux-only RLIMIT_AS repro; the fixture stays within the address space so it is honest on macOS too). A wide-BINDING-ARGUMENT case (`addressSpaceMb: 384`) calls a binding with `[0] * 6_000_000` and asserts the length echoes back: `_lossless_json_violation` runs on model-built arguments that no child-side budget bounds first, and its per-member tuples measured 459.1 MiB against 0.0 MiB for the cursor. A backtracking case returns a 4 MiB string from a binding and asserts it round-trips: the old scalar regex retained engine state proportional to the string's width (146 MiB at 1 MiB, 557.8 MiB at 4 MiB, past the default 512 MiB), which raised MemoryError inside `_pump_replies` and stranded the call to the wall clock. A control-heavy metering case returns 8M NULs under a 16 MiB `maxValueBytes` and asserts `output-limit`, not `exception`: charging by counting instead of materializing the escaped form measured 19.1 MiB against 228.9 MiB for an identical byte count. An addressSpaceMb-baseline case asserts 64 MiB and 32 MiB reject at load with a message naming `addressSpaceMb`, rather than the budget loop's negative admissible limit. A process-identity case asserts the leader's start time reads stably on Linux and reports undefined on Darwin, the guard that keeps a recycled pgid from receiving this run's SIGTERM. A paced-replies case resolves eight 4 MiB values in one `asyncio.gather` round and asserts the frames round-trip; the peak the fix removes (32.0 MiB buffered → 0.0 MiB) lives in the host's fd-3 writable buffer, invisible through the seam, so this case pins the round-trip and the no-regression match but is measured for its peak only out-of-tree. A late-drop case settles the run on `maxWallMs` and resolves the pending binding afterwards, asserting a `timeout` result, an undefined value, and that the late path actually ran — the three assertions all hold pre-fix because `sendReply` already dropped after-settlement values, just later, so the case pins the ordering, not a seam-observable behavior. A binding-all-names case (`rebinds every name the failure path uses`) asserts a real `ValueError` survives send-done binding — a tested fix that rebinds `__main__.ProtocolChannel.send_sync` (and would equally defeat `__main__._encode_json_plain`) and pins the `done` frame against a call-time look-up that skips it; the done-value TOCTOU pre-encoding, the stray-UTF-8 budget-flush retention, and the late-rejection settled guard are counted among the nine no-fail-before fixes (reasons in the Problem section), not pinned by a fail-before test.
 
 ## Alternatives considered
 
@@ -110,4 +124,4 @@ One residual write-path copy is fixed alongside, independent of the config gate:
 
 ## Consequences
 
-The seam's resolve-don't-reject contract holds on the boot-write path and the synchronous-spawn-failure path, both with measured coverage, and neither strands a staging directory. Log capture is thread-safe at the cost of one re-entrant lock acquisition per write and flush, and stray native output is delimited by its own newlines rather than by transport chunks. Fd-3 residual memory is bounded by the actual retained bytes, and both frame readers scan an accumulating frame once rather than quadratically. The output caps admit every value a frame can carry and reject a non-integer budget at load. Disposal is genuinely quiescent against a same-group survivor — bounded by `graceMs + 2 * CLOSE_REAP_MARGIN_MS`, zero-cost when the group is already empty, with the SIGKILL timer cleared once the group empties so a stale kill cannot strike a recycled pgid — RLIMIT enforcement keeps the strictest of configured and inherited on both soft and hard (and the SIGXCPU diagnostic no longer names a budget the host cannot guarantee), bindings called from model-created threads complete instead of timing out, and the handshake frame reader no longer burns the CPU budget on a large program. Every behavioral fix carries a test that fails without it, except the six called out in the Problem section — the chunked frame read (a syscall-count improvement), the confirmed-empty finalize (whose only seam-observable effect freezes at signal delivery, which the pre-fix code also produced), the shared stdout/stderr budget (whose only seam-observable difference turns on nondeterministic cross-pipe arrival timing), the `flush_line` reorder (whose lowered peak stays within what the 12x gate already admits, so no config behaves differently), pacing binding replies (the 32.0 MiB → 0.0 MiB peak reduction lives inside the host's fd-3 writable buffer, unmeasurable through the seam), and dropping a late binding resolution before snapshot (its three assertions all hold pre-fix, so it is not a fail-before case) — so a future regression on the rest goes red.
+The seam's resolve-don't-reject contract holds on the boot-write path and the synchronous-spawn-failure path, both with measured coverage, and neither strands a staging directory. Log capture is thread-safe at the cost of one re-entrant lock acquisition per write and flush, and stray native output is delimited by its own newlines rather than by transport chunks. Fd-3 residual memory is bounded by the actual retained bytes, and both frame readers scan an accumulating frame once rather than quadratically. The output caps admit every value a frame can carry and reject a non-integer budget at load. Disposal is genuinely quiescent against a same-group survivor — bounded by `graceMs + 2 * CLOSE_REAP_MARGIN_MS`, zero-cost when the group is already empty, with the SIGKILL timer cleared once the group empties so a stale kill cannot strike a recycled pgid — RLIMIT enforcement keeps the strictest of configured and inherited on both soft and hard (and the SIGXCPU diagnostic no longer names a budget the host cannot guarantee), bindings called from model-created threads complete instead of timing out, and the handshake frame reader no longer burns the CPU budget on a large program. Every behavioral fix carries a test that fails without it, except the nine called out in the Problem section — the chunked frame read (a syscall-count improvement), the confirmed-empty finalize (whose only seam-observable effect freezes at signal delivery, which the pre-fix code also produced), the shared stdout/stderr budget (whose only seam-observable difference turns on nondeterministic cross-pipe arrival timing), the `flush_line` reorder (whose lowered peak stays within what the 12x gate already admits, so no config behaves differently), pacing binding replies (the 32.0 MiB → 0.0 MiB peak reduction lives inside the host's fd-3 writable buffer, unmeasurable through the seam), dropping a late binding resolution before snapshot (its three assertions all hold pre-fix, so it is not a fail-before case), the done-value TOCTOU pre-encoding (its concurrent-mutation race is not deterministically constructible through the seam, and the daemon-mutation regression's only assertion is probabilistic), the stray-UTF-8 budget-flush retention (a budget flush landing on a multibyte boundary is not schedulable through the seam — v8-ignored), and the late-rejection settled guard (a rejection arriving after settlement is not deterministically constructible from the seam) — so a future regression on the rest goes red.
diff --git a/.agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.zh.md b/.agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.zh.md
index d567ce5886..346e91dab3 100644
--- a/.agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.zh.md
+++ b/.agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.zh.md
@@ -6,7 +6,7 @@ Status: implemented
 
 ## Problem
 
-用于 Code Mode 的 CPython 子进程后端建立在 [fd-3 帧协议](../architecture/2026-07-31-code-runtime-python-fd3-protocol.md)之上，把每个程序结果都 resolve 成一个 `CodeRunResult`，仅在 seam 被误用时才 reject `run()`，并且会 dispose 到完全停稳，从而没有任何留在子进程自己进程组内的子进程存活得比 fiber 更久（一个用 `setsid()` 逃出该进程组的后代是有文档记载的例外——见该包 README 的 Known Limitations）。一连串审查暴露出一些缺陷，它们以单元测试覆盖率无法捕获的方式破坏了这些契约：每一个都藏在一处 `/* v8 ignore */` 之后、一个读起来像修复但实际并非修复的捕获可调用对象之后、一处透过 seam 不可见的内存效应之后、一处重复计数的加载期上界之后、一处存活者能够熬过的进程组升级之后、一处静默死锁的跨事件循环完成之后、一处位于结算路径之外的同步抛出之后，或者一处被当作日志边界处理的传输边界之后。大多数行为修复都附带一个在缺少它时会失败的测试；有六处没有，并被如此标注——分块读取帧（一处系统调用次数的改进，没有可跨平台确定性断言的失败）、确认为空后的收尾（它唯一透过 seam 可观测的效应，即一个冻结的心跳，会在 SIGKILL 被投递的瞬间冻结，而修复前"投递即收尾"的代码也会产生同样的结果，用于区分的探测手段是 Alternatives 以跨环境不可靠为由否决的 signal-0 检查）、共享的 stdout／stderr 预算（它唯一透过 seam 可观测的差异，是一次流中冲刷落在哪条条目边界上，而这取决于两条相互独立的 OS 管道的相对到达时机，`os.sched_yield` 并不能使其确定；它所强化的按管道计的内存界限确实由单管道洪泛测试覆盖），`flush_line` 的 join-清空-push 重排序（它把结算期冲刷的峰值从三份副本降到两份，但 12× 加载门本就覆盖了换行路径的三副本峰值，因此每个被门放行的配置在两种顺序下都落在地址空间之内、不存在透过 seam 可观测的差异——该内存效应在 Python 子进程内部，与共享预算那处一样无法透过 seam 度量），节流 binding 回复（它的树内用例只断言分帧后的回复仍能完整往返；它所移除的峰值位于宿主 fd-3 可写缓冲内部、透过 seam 不可见，因此 32.0 MiB → 0.0 MiB 的降幅只能在树外度量），以及在快照之前丢弃迟到的 binding 解析（它的三条断言在修复前同样成立，因为 `sendReply` 本就丢弃结算之后的值——只是比快照晚）。
+用于 Code Mode 的 CPython 子进程后端建立在 [fd-3 帧协议](../architecture/2026-07-31-code-runtime-python-fd3-protocol.md)之上，把每个程序结果都 resolve 成一个 `CodeRunResult`，仅在 seam 被误用时才 reject `run()`，并且会 dispose 到完全停稳，从而没有任何留在子进程自己进程组内的子进程存活得比 fiber 更久（一个用 `setsid()` 逃出该进程组的后代是有文档记载的例外——见该包 README 的 Known Limitations）。一连串审查暴露出一些缺陷，它们以单元测试覆盖率无法捕获的方式破坏了这些契约：每一个都藏在一处 `/* v8 ignore */` 之后、一个读起来像修复但实际并非修复的捕获可调用对象之后、一处透过 seam 不可见的内存效应之后、一处重复计数的加载期上界之后、一处存活者能够熬过的进程组升级之后、一处静默死锁的跨事件循环完成之后、一处位于结算路径之外的同步抛出之后，或者一处被当作日志边界处理的传输边界之后。大多数行为修复都附带一个在缺少它时会失败的测试；有九处没有，并被如此标注——分块读取帧（一处系统调用次数的改进，没有可跨平台确定性断言的失败）、确认为空后的收尾（它唯一透过 seam 可观测的效应，即一个冻结的心跳，会在 SIGKILL 被投递的瞬间冻结，而修复前"投递即收尾"的代码也会产生同样的结果，用于区分的探测手段是 Alternatives 以跨环境不可靠为由否决的 signal-0 检查）、共享的 stdout／stderr 预算（它唯一透过 seam 可观测的差异，是一次流中冲刷落在哪条条目边界上，而这取决于两条相互独立的 OS 管道的相对到达时机，`os.sched_yield` 并不能使其确定；它所强化的按管道计的内存界限确实由单管道洪泛测试覆盖），`flush_line` 的 join-清空-push 重排序（它把结算期冲刷的峰值从三份副本降到两份，但 12× 加载门本就覆盖了换行路径的三副本峰值，因此每个被门放行的配置在两种顺序下都落在地址空间之内、不存在透过 seam 可观测的差异——该内存效应在 Python 子进程内部，与共享预算那处一样无法透过 seam 度量），节流 binding 回复（它的树内用例只断言分帧后的回复仍能完整往返；它所移除的峰值位于宿主 fd-3 可写缓冲内部、透过 seam 不可见，因此 32.0 MiB → 0.0 MiB 的降幅只能在树外度量），以及在快照之前丢弃迟到的 binding 解析（它的三条断言在修复前同样成立，因为 `sendReply` 本就丢弃结算之后的值——只是比快照晚），完成值的 TOCTOU 预编码（与编码竞态的并发变异无法透过 seam 确定性构造——它的 daemon 变异回归只断言结果永不为 `worker-exit`，这种断言是概率性的、不具有判别力，因此按既有的"无 fail-before 测试且有理由"先例登记为无 fail-before）、stray UTF-8 预算冲刷的扣留（正好落在多字节边界上的预算冲刷无法透过 seam 调度；它被交叉标注为 v8-ignored），以及结算后到达的迟到拒绝的 settled 先查（在运行已经结算之后才到达的拒绝无法从 seam 确定性构造）。
 
 ## Decision
 
@@ -72,11 +72,25 @@ Status: implemented
 
 在此之外还一并修复了一处残余写入路径的复制，它与配置门控相互独立：`_LogStream.write` 的换行分支会在冲刷触发器能够对其设界之前，先把最后一个换行符之后整个未结束的尾部（`text[pos:]`）缓冲进 `_pending`，因此一个早出现的换行符后跟一个巨大的尾部（`"\n" + "A" * 30 MiB`）会对模型自身的字符串再做一份完整副本——正是这条路径存在所要规避的那次 `RLIMIT_AS` 死亡，而且是配置门控无法覆盖的一次，因为该尾部可能远超 `maxLogBytes`。现在该尾部被切到一个 `remaining + 4` 字符的前缀（超过 `remaining` 字符的任何内容都无法被准入，因为字符计数是序列化开销的下界），随后冲刷触发器会用标记将它拒绝。
 
+### 完成值与错误在其校验点处预编码
+
+在 [`py/bootstrap.py`](../../../../packages/code-runtime/code-runtime-python/py/bootstrap.py) 中，`_done_with_value` 现在会在成功路径上把整个终止帧作为一个已预编码的 JSON 字符串返回：被准入的值在这里、在 `_run` 的 `try` 之内的校验点处恰好序列化一次，即 `'{"type": "done", "value": ' + _encode_json_plain(value) + "}"`。程序在返回之后仍可能从 daemon 线程或信号处理器继续变异它返回的 list／dict，因此在一个更晚的点上做第二次遍历会构成一次 TOCTOU——如果一次变异让一个并发变异的后续编码在结算处理器之外抛出，就会把一次已结算的运行在宿主侧降级成 `worker-exit`。在这里、在包裹该调用的 `try` 之内恰好序列化一次，就关上了这个窗口：如果一次并发变异导致编码抛出，异常处理器会把它如实分类为 `exception`；一旦字符串产生出来，该帧就会被逐字写走、不再触碰任何活对象。
+
+`send_done`（`_run` 内部的一个局部函数）通过绑定的 `channel.write_encoded` 写出已预编码的字符串，并在写之前用绑定的 `_encode_json_plain` 编码一个 dict 错误帧——它绝不经 `channel.send_sync`，因为后者的函数体会在调用时刻重新解析 `self.write_encoded` 和模块级的 `_encode_json_plain`。`_encode_json_plain` 与 `channel.write_encoded` 在程序运行前就被绑定进局部变量，理由与 `flush_out`／`flush_err`／`safe_model_traceback` 被绑定相同：程序以 `__main__` 运行，因此 `import __main__; __main__.ProtocolChannel.send_sync = boom` 或 `__main__._encode_json_plain = boom` 本会在调用时刻把发送／编码重新解析成被替换的可调用对象，当该替换抛出时跳过 `done` 帧、把已结算的结论降级成宿主侧的 `worker-exit`。
+
+### 预算触发的冲刷会扣留下一个未完成的多字节尾序列
+
+同样在 [`src/index.ts`](../../../../packages/code-runtime/code-runtime-python/src/index.ts) 中，`flushStray(stray, retainPartialTail)` 在预算触发的冲刷（`captureStray` 中的合并成本阈值）上会把一个未完成的多字节尾部从解码中扣留：当残余以部分 UTF-8 前导序列结束（`stray.utf8.expected > 0`）时，前导字节加上迄今已消耗的续字节（≤3 字节）会从该帧中分离出来作为新的残余，只有完整的前缀被准入并解码。当整个残余就是单个未完序列时什么都不准入，因此一个合法、未完成的字符绝不会在一个被放行、未截断的条目里被渲染成 U+FFFD，也不会推进一条虚假的空条目。被扣留的尾部会从一个全新的 `stray.utf8` 状态重新累计——若用冲刷后 `expected > 0` 的状态来计量它，会把那些被承载下来的前导字节当作非法续字节计费——从而下一个分块能正确地继续推进，且该管道在保留的尾部之上重建其成本／UTF-8 状态。`end`／`closeDeadline` 路径传入 `false`，原样解码整个残余，因为在那里一个不完整的尾序列是真实的坏输入，U+FFFD 才是如实呈现。
+
+### 迟到的 binding 拒绝在格式化错误之前就返回
+
+同样在 `src/index.ts` 中，binding 拒绝的 catch 分支现在会在格式化 `messageOf(error)` **之前**检查 `settled` 并返回。一次在 `maxWallMs`、abort 或 dispose 已经把该运行结算之后才到达的拒绝，本会让 `messageOf(error)` 在这之前运行敌意的 `toString`／`message` getter——为一个结局已定的运行花费宿主堆与时间——然后 `sendReply` 才去窥探 `settled`。及早丢弃这一条已分帧的回复省下了这笔开销。运行中那条本就大致线性的回复排空改用队头游标按数组下标读取、而非 `shift()` 逐项弹出，因此一大轮等待 fd 3 的 `drain` 的宽 binding 的 `asyncio.gather` 会以线性时间排空，而不是因反复切片退化成 O(n²)。
+
 ## Testing
 
 - `tests/boot-write-failure.spec.ts` 对 `spawn` 做 mock，使 fd-3 管道在引导写入时抛出异常（这是真实子进程无法被迫进入的唯一路径），并断言 `run()` resolve 出一个 `worker-exit` 而非 reject。一个同级用例让被 mock 的 `spawn` 同步抛出，并断言 `run()` 仍然 resolve 出一个 `worker-exit`，且会移除它的暂存目录——以被 mock 的 `spawn` 在其 argv 中收到的确切引导路径为准，因此一个同级 worker 的并发暂存不会让它变得不稳定。两者都被隔离在这个 spec 中，因此真实子进程测试套件不受影响。
 - `tests/residual-detach.spec.ts` 对 `detachResidual` 做单元测试：向前传递的副本与残余数据相等、拥有一个大小与其自身长度一致的底层存储（fixture 保持在 Node 的 Buffer 池阈值之上），并且不与源帧的 `ArrayBuffer` 共享。
-- `tests/runtime.spec.ts`：output-cap 用例断言 `ceiling - envelope` 上界（268435392）及其消息。一个 daemon 线程用例驱动四个线程穿过结算的 flush 发出未结束的写入。一个 native-write 用例在抬高后的 `maxLogBytes` 之下，通过 `os.write` 写入 200 KiB 且不含换行符，断言它回读时恰好是一条日志条目（证明散逸输出是按行聚合的，而不是在管道分片边界处被切开）；一个配套用例写入 `b"one\ntwo\nthree"`，断言得到三条条目（证明真正的换行符仍然起分隔作用）。一个 newline-free-flood 用例在一个 4 KiB 的 `maxLogBytes` 之下写入 2 MiB，断言捕获终止于截断标记且保持在预算之内（证明残余数据受账本约束，而不是被整体缓冲）；一个 NUL-flood 配套用例在同一预算之下写入 4000 个不含换行符的 NUL，断言发生截断（证明残余数据是按序列化开销计费的，约为原始的 6 倍，且在度量时不分配转义后的副本）；一个 illegal-UTF-8 用例在一个 3072 字节的预算之下控速发出单字节 `\xff` 写入，并对 `Buffer.concat` 做包装以度量峰值合并缓冲区，断言它保持在 2048 之下（按 U+FFFD 宽度 3 计费时残余数据在约 1024 原始字节处冲刷；一次原始字节的少计会让它达到约 3072，因此该界限具有区分力）；一个 CESU-8/overlong 用例把结构良构但非法的 `ED A0 80` 一次一个字节地控速发出，断言同样的峰值界限（按每序列真实的 9 计费时它提前冲刷；按结构宽度 3 计费会使峰值增至三倍，因此把逐前导字节范围检查回退会使它变红）；一个 broken-multibyte 用例在分开的分片里先写入一个 3 字节的前导字节、再写入一个新的 ASCII 字节，断言同时捕获到一个 `A` 和一个 U+FFFD（覆盖 `accrueStrayCost` 的跨分片断裂序列分支）；一个 post-truncation 用例写入一个 108 字节的载荷（小于最小的 PIPE_BUF，因此是一次原子写入），其首行耗尽一个 64 字节的预算，断言第二行被丢弃（覆盖单次 `data` 回调中的截断后准入空操作，无需 v8-ignore）；一个 short-escape 用例写入一行混合了制表符、引号、反斜杠、一个 `\uXXXX` 控制字符、一个多字节字符和 ASCII 的内容，断言它原样完成往返（覆盖 `jsonStringCostUpTo` 的每一条分支）；一个 reassembly 用例写入一个跨越每个合法多字节前导字节类别（E0 范围、普通 3 字节、F0 和 F4）、越过管道缓冲区的载荷，断言它原样完成往返且不含 U+FFFD（覆盖 `accrueStrayCost` 的逐前导字节范围与跨分片重组）；一个 lone-surrogate 用例在一个 4 KiB 预算之下伪造一个以 1000 个 `\ud800` 转义洪泛的 fd-3 `log` 帧，断言发生截断（该计数正落在计 3 字节会放行、计 6 字节则截断的窗口内，证明该代理项是按其完整转义宽度计费的）；一个 stray-sealing 用例在抬高后的预算之下控速发出 60000 次单字节、不含换行符的 `os.write(1, …)` 调用，并对 `Buffer.concat` 做包装以度量复制量，断言这股细流合并为一条条目、且累积复制量保持在一个实测的 256 KiB 阈值之下（封存后的形态复制约 120 KB，重新合并的形态复制约 538 KB，因此把封存回退成重新合并会使该断言变红——证明分片列表在越过 `MAX_PENDING_CHUNKS` 后封存为块）。一个 closeDeadline-flush 用例让 leader 写入一段不含换行符的诊断，随后 spawn 一个持有管道不放的 `setsid` 孤儿进程，断言该诊断在 `logs` 中存留下来（证明残余数据在截止时间销毁流之前被冲刷）。same-group 回收用例 spawn 一个忽略 SIGTERM 的同进程组后代，它释放管道并递增一个心跳文件；该测试断言在宽限窗口的 SIGKILL 之后心跳停止：无论被杀死的后代是被回收还是作为僵尸进程滞留，这个断言都成立，因此它在 PID 1 不 wait() 孤儿进程的环境下同样成立。一个 dispose-after-resolve 用例断言，对一个已完成、且存在同进程组存活者的运行调用 `dispose()`，只有在该存活者停止执行之后才返回（证明该运行会一直留在 `live` 中，直到它的进程组被回收），并带有一个 `expect(afterDispose).toBeGreaterThan(0)` 守卫，使得当心跳文件从未被写入时，冻结心跳的断言不会被空洞地通过。一个 deadline 用例忙阻塞事件循环越过两个定时器，断言该存活者的心跳冻结（证明轮询的截止时间分支自身发送 SIGKILL，而不是取消尚未触发的升级）。cross-loop 用例在主协程通过 `await asyncio.sleep` 让出时，从一个工作线程自己的 `asyncio.run` 事件循环运行一个绑定，断言该回复完成往返而不是超时；一个配套用例放弃某个线程的调用，使其事件循环关闭，随后在一个后续绑定之前回答它——断言 pump 在关闭事件循环上的 `call_soon_threadsafe` 之后仍然存活（由宿主门控的顺序使其具有确定性，未修复时会把后续绑定拖到墙钟上挂起）。inherited-soft-limit 用例通过一个 `ulimit -S -t` 包装脚本运行解释器，将 CPU 软限制设为低于 `cpuSeconds`，并断言实际应用的 `RLIMIT_CPU` 软限制是继承来的值，而不是配置的值（用 CPU 而非地址空间，因为 macOS 忽略 `ulimit -v`）。一个配套用例继承 1 秒的 CPU 软限制，让程序捕获 SIGXCPU 并忙循环越过它，断言结算复查报告 timeout——证明复查用的是实际生效的软限制，而不是配置的 `cpuSeconds`。一个 control-heavy-diagnostic 用例在一个较小的 `maxValueBytes` 之下抛出一个 NUL 洪泛异常，断言序列化后的帧能放得下（证明该诊断是按序列化开销计量的）。一个 tail-copy 用例（`maxLogBytes: 256`、`addressSpaceMb: 384`）让程序在一个变量里构建一个尾部并写入 `"\n" + tail`，其中 `tail` 为 150 MiB——构建峰值约 2 倍（约 300 MiB，落在地址空间之内，因此模型自身的分配会成功，任何 OOM 都属于缺陷路径），而修复前的整尾重新缓冲会加上第三份约 150 MiB 的副本、越过 384 MiB；切片后的前缀让该次运行得以截断并完成（仅 Linux 的 RLIMIT_AS 复现，macOS 走顺利路径——fixture 自身的构建必须放进地址空间，这是这些 RLIMIT_AS 用例的一条通用规则）。一个 output-budget/address-space 用例断言一个 50 MB 的 `maxLogBytes` 和一个 50 MB 的 `maxValueBytes` 各自对照一个 256 MiB 的 `addressSpaceMb` 在加载期被拒绝（乘以最坏情况的 12 之后超过解释器基线之后剩下的余量），而默认的各项上限对照 512 MiB 则加载成功，对两项预算对称地门控；一个具区分力的用例断言一个 48 MiB 的 `maxLogBytes` 对照一个 512 MiB 的 `addressSpaceMb` 被拒绝——48×8 = 384 MiB 放得进 448 MiB 的可预算余量（旧的 8× 倍数会错误放行），但 48×12 = 576 MiB 放不进。该倍数覆盖的约 12× 峰值来自换行路径上一次接近预算的写入——调用方自己的字符串、行切片与 encode 副本同时存活；结算期 flush 已不再是承重者，因为 `flush_line` 在 push 之前就丢弃了 pending 分块，因此只持有两份副本而非三份。一个 inherited-RLIMIT_AS 用例通过一个 `ulimit -v 131072` 包装层运行解释器，配以一个配置的 512 MiB `addressSpaceMb` 所允许的 32 MiB `maxLogBytes`，断言引导期的重新检查把它作为 `exception` 拒绝、且其消息点名了继承的 RLIMIT_AS（128 MiB 的继承限制在基线之后剩下的太少；仅 Linux，macOS 忽略 `ulimit -v`，该次运行会继续）。一个 non-integer-budget 用例断言一个小数的 `maxLogBytes`／`maxValueBytes` 在加载期被拒绝。一个 combined-peak 用例（`maxLogBytes: 32 MiB`、`maxValueBytes: 32 MiB`、`addressSpaceMb: 512`——每项预算单独都被 12× 门放行）写入约 33M 个不含换行符的星芒面字符（缓冲、未冲刷）后返回约 33M 个星芒面字符，断言该次运行以 `output-limit` 结算（该值本身就超过它 32 MiB 的预算）；修复前未冲刷的日志 pending 加上值的构建加编码峰值会一起越过 512 MiB 地址空间而 OOM，因此在分帧值之前先冲刷日志正是让值检查得以完成的原因（仅 Linux 的 RLIMIT_AS 复现；在 macOS 上超预算的值在两种顺序下都报 output-limit）。一个宽完成值用例（`maxValueBytes: 20 MiB`、`addressSpaceMb: 384`）返回 `[0] * 6_000_000`——JSON 约 12 MB、低于预算，因此必须成功往返；修复前 O(width) 的遍历为每个元素分配遍历元组与编码器栈项（约为序列化尺寸的 28×，超出门保留的 12×），在一个计量器已放行的值上 OOM，而 O(depth) 游标使唯一按宽度分配的只剩输出字符串本身。一个宽 binding 实参用例（`addressSpaceMb: 384`）以 `[0] * 6_000_000` 调用 binding 并断言长度回传：`_lossless_json_violation` 运行在模型构造的实参上，子进程侧没有任何字节预算先行约束，其逐元素元组实测 459.1 MiB，而游标为 0.0 MiB。一个回溯用例从 binding 返回一个 4 MiB 字符串并断言其成功往返：旧的标量正则保留的引擎状态与字符串宽度成正比（1 MiB 时 146 MiB，4 MiB 时 557.8 MiB，超过默认的 512 MiB），会在 `_pump_replies` 内抛出 MemoryError 并把该次调用搁置到墙钟。一个 control-heavy 计费用例在 16 MiB 的 `maxValueBytes` 之下返回 8M 个 NUL，断言得到 `output-limit` 而非 `exception`：以计数替代物化转义形式来计费，在字节数完全相同的前提下实测 19.1 MiB 对 228.9 MiB。一个 addressSpaceMb 下界用例断言 64 MiB 与 32 MiB 在加载期被拒绝，且消息点名 `addressSpaceMb`，而不是预算循环给出的负数上限。一个进程身份用例断言 leader 的启动时刻在 Linux 上可稳定读取、在 Darwin 上报告 undefined，这正是使被复用的 pgid 不会收到本次运行 SIGTERM 的那道守卫。一个 paced-replies 用例在一轮 `asyncio.gather` 中 resolve 八条 4 MiB 的值，断言这些帧能够往返；本修复移除的峰值（32.0 MiB 缓冲 → 0.0 MiB）位于宿主 fd-3 可写缓冲内部、透过 seam 不可见，因此该用例钉住的是往返与无回归匹配，其峰值只能在树外度量。一个 late-drop 用例让该次运行在 `maxWallMs` 上结算，随后才 resolve 那个 pending 的 binding，断言得到一个 `timeout` 结果、一个 undefined 值、且迟到路径确实被执行过——这三条断言在修复前也全部成立，因为 `sendReply` 本就丢弃结算之后的值、只是更晚，因此该用例钉住的是顺序，而非一个透过 seam 可观测的行为。
+- `tests/runtime.spec.ts`：output-cap 用例断言 `ceiling - envelope` 上界（268435392）及其消息。一个 daemon 线程用例驱动四个线程穿过结算的 flush 发出未结束的写入。一个 native-write 用例在抬高后的 `maxLogBytes` 之下，通过 `os.write` 写入 200 KiB 且不含换行符，断言它回读时恰好是一条日志条目（证明散逸输出是按行聚合的，而不是在管道分片边界处被切开）；一个配套用例写入 `b"one\ntwo\nthree"`，断言得到三条条目（证明真正的换行符仍然起分隔作用）。一个 newline-free-flood 用例在一个 4 KiB 的 `maxLogBytes` 之下写入 2 MiB，断言捕获终止于截断标记且保持在预算之内（证明残余数据受账本约束，而不是被整体缓冲）；一个 NUL-flood 配套用例在同一预算之下写入 4000 个不含换行符的 NUL，断言发生截断（证明残余数据是按序列化开销计费的，约为原始的 6 倍，且在度量时不分配转义后的副本）；一个 illegal-UTF-8 用例在一个 3072 字节的预算之下控速发出单字节 `\xff` 写入，并对 `Buffer.concat` 做包装以度量峰值合并缓冲区，断言它保持在 2048 之下（按 U+FFFD 宽度 3 计费时残余数据在约 1024 原始字节处冲刷；一次原始字节的少计会让它达到约 3072，因此该界限具有区分力）；一个 CESU-8/overlong 用例把结构良构但非法的 `ED A0 80` 一次一个字节地控速发出，断言同样的峰值界限（按每序列真实的 9 计费时它提前冲刷；按结构宽度 3 计费会使峰值增至三倍，因此把逐前导字节范围检查回退会使它变红）；一个 broken-multibyte 用例在分开的分片里先写入一个 3 字节的前导字节、再写入一个新的 ASCII 字节，断言同时捕获到一个 `A` 和一个 U+FFFD（覆盖 `accrueStrayCost` 的跨分片断裂序列分支）；一个 post-truncation 用例写入一个 108 字节的载荷（小于最小的 PIPE_BUF，因此是一次原子写入），其首行耗尽一个 64 字节的预算，断言第二行被丢弃（覆盖单次 `data` 回调中的截断后准入空操作，无需 v8-ignore）；一个 short-escape 用例写入一行混合了制表符、引号、反斜杠、一个 `\uXXXX` 控制字符、一个多字节字符和 ASCII 的内容，断言它原样完成往返（覆盖 `jsonStringCostUpTo` 的每一条分支）；一个 reassembly 用例写入一个跨越每个合法多字节前导字节类别（E0 范围、普通 3 字节、F0 和 F4）、越过管道缓冲区的载荷，断言它原样完成往返且不含 U+FFFD（覆盖 `accrueStrayCost` 的逐前导字节范围与跨分片重组）；一个 lone-surrogate 用例在一个 4 KiB 预算之下伪造一个以 1000 个 `\ud800` 转义洪泛的 fd-3 `log` 帧，断言发生截断（该计数正落在计 3 字节会放行、计 6 字节则截断的窗口内，证明该代理项是按其完整转义宽度计费的）；一个 stray-sealing 用例在抬高后的预算之下控速发出 60000 次单字节、不含换行符的 `os.write(1, …)` 调用，并对 `Buffer.concat` 做包装以度量复制量，断言这股细流合并为一条条目、且累积复制量保持在一个实测的 256 KiB 阈值之下（封存后的形态复制约 120 KB，重新合并的形态复制约 538 KB，因此把封存回退成重新合并会使该断言变红——证明分片列表在越过 `MAX_PENDING_CHUNKS` 后封存为块）。一个 closeDeadline-flush 用例让 leader 写入一段不含换行符的诊断，随后 spawn 一个持有管道不放的 `setsid` 孤儿进程，断言该诊断在 `logs` 中存留下来（证明残余数据在截止时间销毁流之前被冲刷）。same-group 回收用例 spawn 一个忽略 SIGTERM 的同进程组后代，它释放管道并递增一个心跳文件；该测试断言在宽限窗口的 SIGKILL 之后心跳停止：无论被杀死的后代是被回收还是作为僵尸进程滞留，这个断言都成立，因此它在 PID 1 不 wait() 孤儿进程的环境下同样成立。一个 dispose-after-resolve 用例断言，对一个已完成、且存在同进程组存活者的运行调用 `dispose()`，只有在该存活者停止执行之后才返回（证明该运行会一直留在 `live` 中，直到它的进程组被回收），并带有一个 `expect(afterDispose).toBeGreaterThan(0)` 守卫，使得当心跳文件从未被写入时，冻结心跳的断言不会被空洞地通过。一个 deadline 用例忙阻塞事件循环越过两个定时器，断言该存活者的心跳冻结（证明轮询的截止时间分支自身发送 SIGKILL，而不是取消尚未触发的升级）。cross-loop 用例在主协程通过 `await asyncio.sleep` 让出时，从一个工作线程自己的 `asyncio.run` 事件循环运行一个绑定，断言该回复完成往返而不是超时；一个配套用例放弃某个线程的调用，使其事件循环关闭，随后在一个后续绑定之前回答它——断言 pump 在关闭事件循环上的 `call_soon_threadsafe` 之后仍然存活（由宿主门控的顺序使其具有确定性，未修复时会把后续绑定拖到墙钟上挂起）。inherited-soft-limit 用例通过一个 `ulimit -S -t` 包装脚本运行解释器，将 CPU 软限制设为低于 `cpuSeconds`，并断言实际应用的 `RLIMIT_CPU` 软限制是继承来的值，而不是配置的值（用 CPU 而非地址空间，因为 macOS 忽略 `ulimit -v`）。一个配套用例继承 1 秒的 CPU 软限制，让程序捕获 SIGXCPU 并忙循环越过它，断言结算复查报告 timeout——证明复查用的是实际生效的软限制，而不是配置的 `cpuSeconds`。一个 control-heavy-diagnostic 用例在一个较小的 `maxValueBytes` 之下抛出一个 NUL 洪泛异常，断言序列化后的帧能放得下（证明该诊断是按序列化开销计量的）。一个 tail-copy 用例（`maxLogBytes: 256`、`addressSpaceMb: 384`）让程序在一个变量里构建一个尾部并写入 `"\n" + tail`，其中 `tail` 为 150 MiB——构建峰值约 2 倍（约 300 MiB，落在地址空间之内，因此模型自身的分配会成功，任何 OOM 都属于缺陷路径），而修复前的整尾重新缓冲会加上第三份约 150 MiB 的副本、越过 384 MiB；切片后的前缀让该次运行得以截断并完成（仅 Linux 的 RLIMIT_AS 复现，macOS 走顺利路径——fixture 自身的构建必须放进地址空间，这是这些 RLIMIT_AS 用例的一条通用规则）。一个 output-budget/address-space 用例断言一个 50 MB 的 `maxLogBytes` 和一个 50 MB 的 `maxValueBytes` 各自对照一个 256 MiB 的 `addressSpaceMb` 在加载期被拒绝（乘以最坏情况的 12 之后超过解释器基线之后剩下的余量），而默认的各项上限对照 512 MiB 则加载成功，对两项预算对称地门控；一个具区分力的用例断言一个 48 MiB 的 `maxLogBytes` 对照一个 512 MiB 的 `addressSpaceMb` 被拒绝——48×8 = 384 MiB 放得进 448 MiB 的可预算余量（旧的 8× 倍数会错误放行），但 48×12 = 576 MiB 放不进。该倍数覆盖的约 12× 峰值来自换行路径上一次接近预算的写入——调用方自己的字符串、行切片与 encode 副本同时存活；结算期 flush 已不再是承重者，因为 `flush_line` 在 push 之前就丢弃了 pending 分块，因此只持有两份副本而非三份。一个 inherited-RLIMIT_AS 用例通过一个 `ulimit -v 131072` 包装层运行解释器，配以一个配置的 512 MiB `addressSpaceMb` 所允许的 32 MiB `maxLogBytes`，断言引导期的重新检查把它作为 `exception` 拒绝、且其消息点名了继承的 RLIMIT_AS（128 MiB 的继承限制在基线之后剩下的太少；仅 Linux，macOS 忽略 `ulimit -v`，该次运行会继续）。一个 non-integer-budget 用例断言一个小数的 `maxLogBytes`／`maxValueBytes` 在加载期被拒绝。一个 combined-peak 用例（`maxLogBytes: 32 MiB`、`maxValueBytes: 32 MiB`、`addressSpaceMb: 512`——每项预算单独都被 12× 门放行）写入约 33M 个不含换行符的星芒面字符（缓冲、未冲刷）后返回约 33M 个星芒面字符，断言该次运行以 `output-limit` 结算（该值本身就超过它 32 MiB 的预算）；修复前未冲刷的日志 pending 加上值的构建加编码峰值会一起越过 512 MiB 地址空间而 OOM，因此在分帧值之前先冲刷日志正是让值检查得以完成的原因（仅 Linux 的 RLIMIT_AS 复现；在 macOS 上超预算的值在两种顺序下都报 output-limit）。一个宽完成值用例（`maxValueBytes: 20 MiB`、`addressSpaceMb: 384`）返回 `[0] * 6_000_000`——JSON 约 12 MB、低于预算，因此必须成功往返；修复前 O(width) 的遍历为每个元素分配遍历元组与编码器栈项（约为序列化尺寸的 28×，超出门保留的 12×），在一个计量器已放行的值上 OOM，而 O(depth) 游标使唯一按宽度分配的只剩输出字符串本身。一个宽 binding 实参用例（`addressSpaceMb: 384`）以 `[0] * 6_000_000` 调用 binding 并断言长度回传：`_lossless_json_violation` 运行在模型构造的实参上，子进程侧没有任何字节预算先行约束，其逐元素元组实测 459.1 MiB，而游标为 0.0 MiB。一个回溯用例从 binding 返回一个 4 MiB 字符串并断言其成功往返：旧的标量正则保留的引擎状态与字符串宽度成正比（1 MiB 时 146 MiB，4 MiB 时 557.8 MiB，超过默认的 512 MiB），会在 `_pump_replies` 内抛出 MemoryError 并把该次调用搁置到墙钟。一个 control-heavy 计费用例在 16 MiB 的 `maxValueBytes` 之下返回 8M 个 NUL，断言得到 `output-limit` 而非 `exception`：以计数替代物化转义形式来计费，在字节数完全相同的前提下实测 19.1 MiB 对 228.9 MiB。一个 addressSpaceMb 下界用例断言 64 MiB 与 32 MiB 在加载期被拒绝，且消息点名 `addressSpaceMb`，而不是预算循环给出的负数上限。一个进程身份用例断言 leader 的启动时刻在 Linux 上可稳定读取、在 Darwin 上报告 undefined，这正是使被复用的 pgid 不会收到本次运行 SIGTERM 的那道守卫。一个 paced-replies 用例在一轮 `asyncio.gather` 中 resolve 八条 4 MiB 的值，断言这些帧能够往返；本修复移除的峰值（32.0 MiB 缓冲 → 0.0 MiB）位于宿主 fd-3 可写缓冲内部、透过 seam 不可见，因此该用例钉住的是往返与无回归匹配，其峰值只能在树外度量。一个 late-drop 用例让该次运行在 `maxWallMs` 上结算，随后才 resolve 那个 pending 的 binding，断言得到一个 `timeout` 结果、一个 undefined 值、且迟到路径确实被执行过——这三条断言在修复前也全部成立，因为 `sendReply` 本就丢弃结算之后的值、只是更晚，因此该用例钉住的是顺序，而非一个透过 seam 可观测的行为。一个"绑定全部用名"用例（`rebinds every name the failure path uses`）断言一个真实的 `ValueError` 在 send-done 绑定之后仍然存活——这是一个有测修复，它同时绑定 `__main__.ProtocolChannel.send_sync`（对 `__main__._encode_json_plain` 同样有效）并用它钉住 `done` 帧不被一次调用时刻的查找跳过；而完成值的 TOCTOU 预编码、stray UTF-8 预算冲刷的扣留与结算后到达的迟到拒绝的 settled 先查，都被计入那九处无 fail-before 修复（理由见 Problem 段），不由 fail-before 测试钉住。
 
 ## Alternatives considered
 
@@ -110,4 +124,4 @@ Status: implemented
 
 ## Consequences
 
-seam 的"只 resolve、不 reject"契约在引导写入路径和同步 spawn 失败路径上都得以成立，两者的覆盖率都是被度量的，且两者都不会遗留一个暂存目录。日志捕获是线程安全的，代价是每次写入和 flush 都要获取一次可重入锁，并且散逸的原生输出由它自己的换行符来分隔，而不是由传输分片来分隔。fd-3 残余数据的内存受实际保留的字节数约束，并且两个帧读取器都以一次而非平方级的方式扫描一个不断累积的帧。输出上限放行一个帧所能承载的每一个值，并在加载期拒绝一个非整数的预算。dispose 面对同进程组存活者是真正完全停稳的（以 `graceMs + 2 * CLOSE_REAP_MARGIN_MS` 为界，在进程组已为空时代价为零，并且一旦进程组清空就清除 SIGKILL 定时器，从而一次滞留的 kill 无法击中一个被回收的 pgid），RLIMIT 强制在 soft 和 hard 两者上都保持配置值与继承值中的最严格者（并且 SIGXCPU 诊断不再把一个宿主无法保证的预算说出来），并且从模型创建的线程调用的绑定会完成而不是超时，而且握手帧读取器不再在一个大程序上烧掉 CPU 预算。每处行为修复都附带一个在缺少它时会失败的测试，除了 Problem 一节点出的那六处——分块读取帧（一处系统调用次数的改进）、确认为空后的收尾（它唯一透过 seam 可观测的效应会在信号投递时冻结，而修复前的代码也会产生同样的结果）、共享的 stdout／stderr 预算（它唯一透过 seam 可观测的差异取决于不确定的跨管道到达时机），`flush_line` 重排序（它降低后的峰值仍落在 12× 门本就放行的范围内，因此没有配置会有不同表现）、节流 binding 回复（32.0 MiB → 0.0 MiB 的峰值降幅位于宿主 fd-3 可写缓冲内部、透过 seam 不可度量），以及在快照之前丢弃迟到的 binding 解析（它的三条断言在修复前同样成立，因此不是一处缺代码即变红的用例）——因此其余各处未来若发生回归都会变红。
+seam 的"只 resolve、不 reject"契约在引导写入路径和同步 spawn 失败路径上都得以成立，两者的覆盖率都是被度量的，且两者都不会遗留一个暂存目录。日志捕获是线程安全的，代价是每次写入和 flush 都要获取一次可重入锁，并且散逸的原生输出由它自己的换行符来分隔，而不是由传输分片来分隔。fd-3 残余数据的内存受实际保留的字节数约束，并且两个帧读取器都以一次而非平方级的方式扫描一个不断累积的帧。输出上限放行一个帧所能承载的每一个值，并在加载期拒绝一个非整数的预算。dispose 面对同进程组存活者是真正完全停稳的（以 `graceMs + 2 * CLOSE_REAP_MARGIN_MS` 为界，在进程组已为空时代价为零，并且一旦进程组清空就清除 SIGKILL 定时器，从而一次滞留的 kill 无法击中一个被回收的 pgid），RLIMIT 强制在 soft 和 hard 两者上都保持配置值与继承值中的最严格者（并且 SIGXCPU 诊断不再把一个宿主无法保证的预算说出来），并且从模型创建的线程调用的绑定会完成而不是超时，而且握手帧读取器不再在一个大程序上烧掉 CPU 预算。每处行为修复都附带一个在缺少它时会失败的测试，除了 Problem 一节点出的那九处——分块读取帧（一处系统调用次数的改进）、确认为空后的收尾（它唯一透过 seam 可观测的效应会在信号投递时冻结，而修复前的代码也会产生同样的结果）、共享的 stdout／stderr 预算（它唯一透过 seam 可观测的差异取决于不确定的跨管道到达时机），`flush_line` 重排序（它降低后的峰值仍落在 12× 门本就放行的范围内，因此没有配置会有不同表现）、节流 binding 回复（32.0 MiB → 0.0 MiB 的峰值降幅位于宿主 fd-3 可写缓冲内部、透过 seam 不可度量），在快照之前丢弃迟到的 binding 解析（它的三条断言在修复前同样成立，因此不是一处缺代码即变红的用例），完成值的 TOCTOU 预编码（它的并发变异竞态无法透过 seam 确定性构造，而 daemon 变异回归的唯一断言是概率性的），stray UTF-8 预算冲刷的扣留（落在多字节边界上的预算冲刷无法透过 seam 调度——v8-ignored），以及结算后到达的迟到拒绝的 settled 先查（结算之后才到达的拒绝无法从 seam 确定性构造）——因此其余各处未来若发生回归都会变红。