feat: connect interactive Zsh to one helper child

build.zig

@@ -34,6 +34,8 @@ pub fn build(b: *std.Build) void {
     const native_fs_application_profile = b.option(bool, "native-fs-application-profile", "Separate bounded Zsh application composition; existing ABI31 owner") orelse false;
     if (native_fs_application_profile and (!native_fs_owner_stack or release_artifact)) @panic("filesystem application profile requires its private ABI31 owner-stack profile");
     options.addOption(bool, "native_fs_application_profile", native_fs_application_profile);
+    const native_zsh_external = b.option(bool, "native-zsh-external", "Private selected Zsh parent and one immutable helper child") orelse false;
+    options.addOption(bool, "native_zsh_external", native_zsh_external);
     const native_zsh_terminfo = b.option(bool, "native-zsh-terminfo", "Private large-Zsh MODE/SIGINT composition with retained Owner namespace custody") orelse false;
     options.addOption(bool, "native_zsh_terminfo", native_zsh_terminfo);
     const block_test = b.option([]const u8, "block-test", "Disposable disk bring-up: write or verify");
@@ -240,6 +242,8 @@ pub fn build(b: *std.Build) void {
     options.addOption(bool, "native_tty_signal_probe", native_tty_signal_probe);
     if (native_zsh_terminfo and (!native_fs_application_profile or !native_tty_mode_probe or !native_tty_signal_probe))
         @panic("Zsh terminfo requires its private large-application MODE and exact-generation SIGINT closure");
+    if (native_zsh_external and (!native_zsh_terminfo or !native_process_copy or !native_process_exec or !native_copy_signals or !native_signal_actions or !native_signal_public or !native_signal_suspend or !native_parent_identity))
+        @panic("Zsh external requires its selected terminfo, copy/exec and generation-safe child signal closure");
 
     options.addOption(bool, "native_exec_copy", negativeOption(b, release_artifact, af09_diagnostic, "native-exec-copy", "Copy an unpublished replacement for rejection testing"));
     options.addOption(bool, "native_exec_early", negativeOption(b, release_artifact, af09_diagnostic, "native-exec-early", "Publish replacement before owner confirmation"));

docs/NATIVE-C.md

@@ -242,6 +242,30 @@ and compact hashes are in [results](evidence/af07-owner-native-2026-10-23/README
 No new VM before fresh one-sequence disposition. A successful diagnostic without
 recurrence does not resolve the panic or authorize resumed affected acceptance.
 
+## Selected external-Zsh Owner capacity
+
+The [issue143 owner decision](https://github.com/gonz0w/Aether/issues/143#issuecomment-6591806304)
+selects73,728 Owner RX bytes and a12,288-byte mapped stack (12,280 usable)
+only with the existing `native-zsh-external` closure. AENFS006/AENMX011 bytes do
+not select this allowance: the kernel boot gate and loader explicitly choose
+`parseExternalApplication`; old `parseApplication`, owner-stack and other
+profiles retain their original code, stack and envelope limits.
+
+The selected stack grows downward to `[0x7ff000,0x802000)`, with three zeroed
+RW/NX pages and absent guards at0x7fe000 and0x802000. ABI31, initial
+RSP0x802000-8 and the8KiB data region at0x900000 stay exact. Runtime and
+workspace remain4,096 bytes each. Maximum mapping is18 RX+3 stack+2 data pages,
+23 of the existing128 Owner pages; total application backing stays11,520 pages.
+This adds no allocator, syscall, namespace grant or peer mapping authority.
+
+`scripts/owner_stack.py` accepts an explicit `stack_bytes=12288` for this fit;
+its4KiB default,8KiB selection and dynamic/recursive/unknown-edge rejection
+remain. Run the pure inspector and fixture-source controls with
+`python3 -B -m unittest discover -s tests -p test_zsh_owner_capacity.py -v`.
+The same test file supplies actual parser/boot/mapping body fixtures for bounded
+Zig execution recorded separately. These host checks do not execute page tables
+or qualify a guest. Fresh matched fit and separate review still precede an image.
+
 ## Guarded complete-owner candidate — AENFS005 / ABI31
 
 The maintainer approved a separate8KiB guarded stack and measurement-led code
@@ -4577,3 +4601,47 @@ The syscall scaffold executes the actual write, query and reset bodies over host
 storage. It does not establish hardware protection, linked static growth or a
 native reader result. Those remain matched kernel/artifact gates. Routine reviewed
 checks follow the [standing execution direction](policy/execution.md#current-milestone-execution-direction-2026-11-01).
+
+
+## Selected Zsh parent/helper kernel composition
+
+Issue143 adds default-off `-Dnative-zsh-external=true`, requiring the existing
+terminfo, copy/exec, copied signal actions, public actions, suspension and parent
+identity selections. The exact Owner/A001 launch admits only parent1/C002.
+Cooperative freeze accepts that live bound parent or its exact child2; only the
+Owner may copy parent1 into unadmitted child2. The child receives a fresh native
+generation and clock binding with retained namespace provenance only, process
+endpoints and explicitly null TTY signal ownership. Owner generation0 remains
+valid for the parent. Existing selected startup omits namespace/AENAP export.
+
+Only child2 can replace its image with the Owner-held C003 helper. Its current
+parent relationship, child clock and namespace provenance must still match;
+exec preserves native generation/binding and the existing receipt/publication
+transaction. Parent exec and other copy targets remain denied. Existing
+SIGCHLD17 validates the real parent generation. Ordinary profiles retain their
+limits; this external profile uses only the
+[approved Owner capacity](#selected-external-zsh-owner-capacity). See the selected
+[parent/helper contract](../userland/docs/ZSH-FILESYSTEM.md#selected-parenthelper-extension).
+
+The fixed issue143 target trial passed in34.169s: actual Zsh launched the held
+helper, collected status7, printed7 and returned to its prompt before normal
+parent/engine exit and export. The Owner completed33/96 requests with mode
+cleanup0; all21 cleanup phases and three reclamations completed, with halt
+at2884/6000ticks. Screen/PTY and once-only staged input were observed; all
+original host holders and clients were reaped with absent groups and output EOF.
+[PR144](https://github.com/gonz0w/Aether/pull/144) records the source delivery.
+This is the approved fixed-workload checkpoint, with full-host coverage still
+open in [issue141](https://github.com/gonz0w/Aether/issues/141). General resource
+peaks, arbitrary filesystem execution, child input/job control, login, persistent
+shell writes/reboot readback, packages and R1 remain separate gates.
+
+Run focused public source checks from the repository root:
+
+```sh
+python3 -B -m unittest discover -s tests -p test_native_zsh_external.py -v
+```
+
+The actual-body fixture uses real Binding/Pending and copy/exec/freeze/notification
+bodies over host storage; MMU/device/scheduler installation is substituted. Its
+private qualified compiler entry and cleanup records remain separate from these
+stdlib-only public checks. No private runner API is required by the public test.

docs/policy/execution.md

@@ -167,6 +167,57 @@ No extra guest, unknown-effect retry or cleanup authority follows. External
 commands, login, persistent write/reboot/readback, packages and R1 retain their
 own gates. The earlier design and fixed diagnostic-fit decisions remain effective.
 
+## Selected Zsh parent/helper composition —2026-11-02
+
+Cam directly approved
+[the scoped parent/helper design](https://github.com/gonz0w/Aether/issues/142#issuecomment-6589424662):
+“Approve scoped parent/helper design (Recommended)”. Reviewed proposal03 in
+issue142 selects one real Zsh parent and one immutable helper child with the
+actual internal pipe, existing copy/exec/SIGCHLD, one context per process and
+Rust Owner namespace custody. [Issue143](https://github.com/gonz0w/Aether/issues/143)
+owns implementation; the [local consumer contract](../../userland/docs/ZSH-FILESYSTEM.md#selected-parenthelper-extension)
+records the selected ownership and compatibility requirements.
+
+Child bindings are local to its real native slot/generation. MODE/private restore
+and SIGINT stay parent-only; child SIGINT ownership is explicitly null. Only
+READ/WRITE proxy descriptions are delegated, with an exclusive read lease and
+truthful unsupported canonical/ISIG child input. Use complete336-byte selected
+snapshots, preserve old304-byte profiles, and retain actual wait status through
+known delivery/collection, reclaim and parent read-lease restoration. Unknown
+effects contain without replay. No namespace grant, new syscall/capability kind,
+global process table or numeric limit increase is selected.
+
+This approves scoped implementation under the standing milestone direction.
+Correct and measure the known oversized external frame before any image; fresh
+actual integrated fits and applicable verification/artifact/media/cleanup gates
+remain. No image/run result, general utility or filesystem-exec installation,
+child job control/input, login, persistence, package or R1 acceptance is claimed.
+Issue137's diagnostic-fit/full-host exceptions remain issue-only; issue141 retains
+its failed coverage and unverified cleanup.
+
+## Selected issue143 capacity and verification decision —2026-11-02
+
+Owner direction,2026-11-02: Cam directly approved the
+[scoped issue143 plan](https://github.com/gonz0w/Aether/issues/143#issuecomment-6591806304), including the reviewed proposal in comment6591273627.
+Only native-zsh-external/native_zsh_process may use73,728 bytes of Owner RX
+code and a12,288-byte mapped stack (12,280 usable), within unchanged128-page
+Owner backing. Preserve ABI31/RSP0x802000-8, Runtime/workspace4,096 each,
+RW/NX stack, absent guards and old-profile code/stack/parser/boot limits.
+Fresh matched selected fit, boundary/guard tests and separate artifact/media
+review precede an image/trial. The one fixed helper/status7/parent-prompt/clean
+exit trial may establish remaining scoped workload fit despite unknown complete
+parser/handler/heap/copied-peak proof. No general peak qualification follows.
+Focused contract checks, separate review, required protected CI and successful
+exact trial may qualify this issue143 checkpoint while issue141's full-root
+integration gate stays open. This is an explicit issue143 policy exception,
+not a full-host pass or transfer of issue137's exceptions. Preserve unknown
+history/quarantines. Other app/time/request/mutation/capture/no-network,
+disposable-media, finite-attempt and known-cleanup limits remain binding.
+Login, persistence/reboot, packages, assembled-system and R1 gates remain separate.
+Routine implementation, builds, reviewed bounded tests and delivery proceed
+under standing approval; this decision grants no new syscall/capability kind,
+arbitrary executable authority or unknown-effect retry.
+
 ## Ordinary-app namespace and clock contract —2026-10-28
 
 The owner approved the separately reviewed [issue98 proposal02](https://github.com/gonz0w/Aether/issues/98#issuecomment-6477628920)

docs/workflow.json

@@ -2665,6 +2665,16 @@
       "invariants": "One retained Owner namespace Client/epoch; exact app generation; readonly closed336/AEFP0004; actual held directory, no fake stat; AENAP002 process-only transfer and positive large/MODE/SIGINT closure. Existing resource/default/cleanup limits; old profiles preserved. Application boot-module bound derives from existing AENFS006 component caps; ordinary/large defaults unchanged. Fixed Screen4 private FIFO and original live holder association survive closed diagnostic pipes.",
       "oracle": "Actual realproducer epoch/inplace constructor and semantic omissions; exact libc/raw errno/mask/publication; compiled app/Owner origins, derived-source pins, current loader/TLS/layout/stack; known child cleanup and real hostVT100 input/render/exit. Actual extracted boot guard admits selected9,081,744/exactcap and rejects one-over/u64max before dispatch; compiling old/omitted gate controls reject. Source-only public checks are distinct from the private actual compiler run.",
       "gaps": "No current image/guest or complete Zsh startup/parser/handler stack/peakheap/whole-session request demand. Expected33requests and capacity are models, not native evidence; externalexecute still overbudget. Unknown historical interrupted hostattempt remains quarantined."
+    },
+    {
+      "id": "zsh-external-parent-helper",
+      "reference": "userland/docs/ZSH-FILESYSTEM.md",
+      "invariants": "Selected one-parent/one-helper copy/exec/wait with full descriptor snapshots, Owner namespace custody, child-local binding, parent-only MODE/SIGINT, shared FILE lifetime, known wait delivery before reclaim/read-lease restoration. External Owner RX73728/stack12288 within128 backing; old profiles and other execution bounds stay exact.",
+      "command": "python3 -B -m unittest discover -s tests -p test_native_zsh_external.py -v; python3 -B -m unittest discover -s tests -p test_zsh_owner_capacity.py -v; actual changed parser/boot/mapping bodies and C/Rust controls in the owning qualified private recipes; lead-frozen selected target/Owner fit, reviewed image/media and fixed native helper/status/prompt workload.",
+      "oracle": "Real helper ELF executes and exits7; Zsh observes actual status7 and returns to its prompt; normal final app/engine exit, mode restoration, export and three known reclamations. Qualified issue143 fixed trial:33/96 requests,21 cleanup phases, halt2884/6000ticks, known host cleanup. Malformed/stale/unknown effects contain without replay.",
+      "gaps": "Approved comment6591806304 limits acceptance to the fixed helper/status/prompt workload and selected Owner capacity. Full-root141 stays open. No full-host/general peak, child input/job control, arbitrary filesystem exec, login, persistent shell write/reboot readback, packages or R1 qualification. Private recipes are not a standalone distribution.",
+      "owner": "Aether kernel, userland and sys-init",
+      "budget_seconds": 300
     }
   ]
 }