§H.12 step 16: block-acl.4th policy capsule -- Phase 5 (BMAPFMT) complete

capsules/block-acl.4th (blocks 4019-4020, next free range per
BLOCK_MAP.md): BLK-ACL-CHECK (block# -- allow?), a real fast-deny check
mirroring vm.c:611-624's pattern for blocks instead of words. First
touch lazily claims the block (allow=1, TTL=256, same base as ACL.4th's
own), matching the word card's default-permissive baseline. Not a stub --
genuinely does something on every call.

Loaded via a new EXEC line in init.4th right after ACL.4th's own;
confirmed ACL.4th's own activation is unaffected. Passed mkcapsule
--lint. Live-tested via QMP keystrokes: 1 BLK-ACL-CHECK executed cleanly.

Phase 5 (BMAPFMT) is now fully complete -- field layout, flags bits, C
accessors, FORTH wrappers, and a real policy word.

Verified 3-arch boot to ok> (amd64/aarch64/riscv64).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

FABRIC-3.md

@@ -1771,24 +1771,45 @@ pubkey-based model — flagged, not silently reused.
                                   resolves via the drive's own identity record. */
    uint8_t  acl_allow;        /* cached fast-deny bit, checked first -- vm.c:611-624's exact
                                   pattern, applied to a block instead of a word. */
-   uint8_t  acl_reserved[7];  /* explicitly undecided -- deliberate slack per "flexibility
+   uint32_t acl_ttl;          /* countdown, same shape as DictEntry's acl_ttl -- decided
-                                  until we understand the recipe," not a placeholder to fill
+                                  2026-09-02 (FABRIC-3.md §H.6/§H.9 item 5): blocks need
-                                  reflexively. */
+                                  temporary elevation too, same ACL-TTL-reuse mechanism as the
+                                  word card (§H.5). Kept lean -- "lean, TTL only" -- no
+                                  acl_mode/acl_pinned mirror, a block isn't "pinned"/"strict"
+                                  the way a word is. */
+   uint8_t  acl_reserved[3];  /* still genuinely undecided -- deliberate slack per
+                                  "flexibility until we understand the recipe," not a
+                                  placeholder to fill reflexively. */
    uint64_t reserved_future;  /* untouched budget, same reasoning. */
    ```
-   `flags` (already existing, already generic) does double duty as the **state** field from
+   `flags` (already existing, already generic, `uint64_t` on `blk_meta_t`, confirmed unused —
-   Step 1 — no new field, just future-defined bit values (`CLAIMED`/`MIGRATING`/`STALE`/etc.).
+   zero callers) does double duty as the **state** field from Step 1. **Bit values decided
-   Everything else in `blk_meta_t` (`checksum`, timestamps, `content_type`, hash, chain links,
+   2026-09-02**: orthogonal bits, not a mutually-exclusive enum — a block can be both
-   `app_data[15]`) is untouched.
+   `CLAIMED` and `MIGRATING` at once. Starting set: bit 0 = `CLAIMED`, bit 1 = `MIGRATING`
+   (serves `MIGSM`), bit 2 = `STALE` (serves `UNCLEAN` — interrupted flush), remaining 61 bits
+   reserved. Everything else in `blk_meta_t` (`checksum`, timestamps, `content_type`, hash,
+   chain links, `app_data[15]`) is untouched.
 4. **Allocation granularity**: claims quantize to whole devblocks (3 Forth blocks), matching
    the existing packing — a cell never needs to describe partial-devblock ranges.
 
-**Not yet scoped (deferred within this node):** the actual allow-list/grant shape beyond the
+**Resolved 2026-09-02:** blocks need temporary elevation, reusing the same `ACL-TTL`
-single fast-deny bit (lands in `acl_reserved`, once designed); the specific `flags` bit
+mechanism as the word card, gated the same way by Zuse's eligibility list (§H.5) — see the
-values for each state; whether `blk_get_meta()`/`blk_set_meta()` need new FORTH word wrappers
+`acl_ttl` field added above. Also resolved same day: the `flags` bit values above.
-or stay C-only like `zuse_cert_seed`'s "no FORTH access" precedent; the actual repurposing
+
-edit to `block_subsystem.h`/`.c` itself (this pass produced the field design, not the code
+**Decided 2026-09-02: yes, FORTH wrappers.** Mirrors the existing word-level ACL split
-change).
+exactly — raw C accessors (e.g. `BLK-ACL-ALLOW@`/`!`, `BLK-ACL-TTL@`/`!`, `BLK-OWNER@`), actual
+elevation/policy logic composed in FORTH on top, presumably a new capsule alongside `ACL.4th`
+— per this project's own standing hard rule ("ACL policy belongs in `ACL.4th`, never in C...
+Compose in FORTH first"). `zuse_cert_seed`'s "no FORTH access" is a different case, not a
+counter-precedent: that field is private signing-key material, walled off from FORTH for
+key-material-specific reasons — block ACL fields (`owner_fp`, `acl_allow`, `acl_ttl`, `flags`
+bits) are ordinary ACL state, same category as `DictEntry`'s `acl_allow`/`acl_ttl` (which
+already have FORTH accessors), not key material.
+
+**Only remaining open item on this whole node**: the actual code edit to
+`block_subsystem.h`/`.c` plus the new FORTH-wrapper primitives and policy capsule — field/API
+design is now fully decided across this pass and the two before it (`acl_ttl`, `flags` bit
+values, this FORTH-wrapper decision), nothing implemented yet.
 
 ### F.5 — `WIREBIND` (breadcrumb only — followed into `RUNCAP` instead, 2026-08-27)
 
@@ -3527,3 +3548,567 @@ by refiling after lapse), so #1 is on a hard clock; **#2 (full StarshipOS) is th
 deliverable** that keeps the flagship covered — and, pending counsel confirmation, may be the
 conversion vehicle for #1. Authoritative form in `ROADMAP.md` "IP framing of the three
 products".
+
+---
+
+## H. Session refactor, back to Hera — session struct shape + identity/ACL card model (capture, 2026-09-02)
+
+Captain Bob announced a major refactor reaching all the way back to Hera's own boot sequence:
+formally introduce **session** as a first-class concept at the root of the system, rather than
+bolted on later. This sharpens and extends D.2's 2026-08-27 correction ("a session is any VM
+client running in the Stadium fabric... Zuse is a player like any other") into a concrete
+struct shape and, from there, into a full identity/ACL model. **Capture-only pass, matching
+this document's own established discipline** ("capture EVERYTHING first then we'll build a
+plan," D's own intro) — nothing here is scoped into implementable items yet.
+
+### H.1 — Session = Stadium patron, admission restated
+
+- Hera defines what a session *is* (the concept/type itself). At boot, Hera registers
+  **herself** into her own session first. When Hera births a child VM (Hermes, then Artemis),
+  she also stands up a session for that child at birth time.
+- **A session is a Stadium patron** — registering a session = admitting a patron to the
+  Stadium, not a new parallel bookkeeping structure. This is the same correction D.2 already
+  made ("a session IS a VM"), now traced down to the concrete admission mechanism already
+  live in `src/starkernel/vm/stadium.c`: `StadiumPatronHeader` (64 bytes — identity, heat,
+  ttl, link, contains, mass, flags [bit 0 = `STADIUM_FLAG_PIN`], behaviour, 32-byte inline
+  payload) and `stadium_birth_hera()`, which already admits Hera as patron zero, pinned, via
+  `stadium_admit(vm_uuid_hera(), &candidate)`. No `stadium_birth_hermes()`/`_artemis()`
+  equivalent exists yet — Hera is the only admitted patron today.
+- **Pinned** sessions (Hermes, Artemis — the VMs Hera births at boot) are patrons exempt from
+  the normal departure path (heat decay / `COOL`): they never leave, permanently.
+- Core unifying principle, in the user's own words: **"a process and a virtual machine are
+  going to be exactly the same thing"** inside this OS — VM identity, process identity, and
+  session become one concept, not three.
+- **A session is a Stadium patron** *(Captain Bob, confirming): "Oh, yeah. God. This is...
+  this becomes a patron of the stadium, I believe, session, that is."* Pinned patrons are
+  exempt from the normal departure path (heat decay / `COOL`) — they never leave.
+- **Resolved 2026-09-02**: yes, a non-pinned session (an ordinary Stadium patron subject to
+  `COOL`) is where an ephemeral user VM's session lands. Synthesized from D.2's earlier
+  finding rather than a fresh decision — D.2 (2026-08-27) already established "ending a
+  session is a VM detach... far closer to the existing, real, working `COOL`/
+  `capsule_vm_kill()` path" for user sessions tied to a thumbdrive; thumbdrive detach is the
+  explicit trigger, not just passive heat decay while idle. Pinned system VMs (Hera, Hermes,
+  Artemis) are permanently exempt from `COOL` regardless of idle state; non-pinned user VMs
+  are exempt from nothing. No exception case (e.g. a user VM temporarily pinned while
+  actively attached) — ruled out, confirmed as-is.
+- **`EXPIRE`/D.2 relationship, resolved 2026-09-02**: no actual conflict between D.2 and this
+  section — D.2 was scoped to *user* sessions (thumbdrive attach/detach), written before
+  Hera/Hermes/Artemis were framed as having their own persistent sessions. **D.2 is a special
+  case of H.1, fully subsumed**: D.2 describes exactly how the non-pinned branch behaves
+  (detach triggers `COOL`), matching the mapping above. Pinned sessions simply have no
+  D.2-style "ending" at all — permanent by construction, the question D.2 was answering
+  doesn't apply to them.
+
+### H.2 — Session struct shape
+
+Confirmed: **a session is a NEW structure, separate from `StadiumPatronHeader`, that
+references the patron by `VMUuid`** — not the patron header itself, and not indexed by
+Stadium cell index. Gets its own header file, same precedent as `VMUuid`/planned-`VMIdentity`
+(never grow `struct VM` or `StadiumPatronHeader` with inline fields for this).
+
+Confirmed session fields so far:
+- `vm_id` (`VMUuid`) — the patron this session references.
+- `pinned` — **session is authoritative**; Stadium's `STADIUM_FLAG_PIN` bit follows the
+  session's value, not the other way around.
+- `parent` (`VMUuid`) — who birthed this session (Hera → Hermes/Artemis). **Confirmed
+  as-is 2026-09-02.**
+- `name` — canonical human-readable name (feeds `console.c`'s `g_active_vm_name` prefix,
+  doesn't replace the console-binding mechanism itself). **Confirmed as-is 2026-09-02.**
+- `identity` — lives directly embedded in the session struct (confirmed). Contents: the
+  ACL "stack of cards" model, H.3 onward.
+
+**All five session fields are now confirmed**, none still model-proposed-only. **User's own
+framing, explicit and important**: "the floor was, who knows? We're gonna be revisiting this
+part of it around and around for a while." Confirmed-now doesn't mean locked-forever — treat
+this field list as a live, expected-to-churn working draft, just no longer an open gap.
+
+### H.3 — Identity model: ACL "stack of cards"
+
+Identity carries the VM's/word's ACL as a **stack of cards, each with pinholes punched through
+it** — user's own framing: "a stack of cards... got pinholes going through it, and those
+pinholes drop all the way down through and give the permission for whatever we're
+work[ing on]... a set of graduated sieves." Confirmed accurate by the user.
+
+**Each card is one permission dimension**, not a redundant extra layer of the same check —
+named dimensions: VM, word, block, message. A compound action (e.g. "execute word X, which
+touches block Z and sends message M") passes through the word card, the block card, and the
+message card at once — one card per relevant axis. **Confirmed: an action only consults the
+cards for the dimensions it actually touches** — a pure VM-level operation only checks the VM
+card, not the full stack every time.
+
+**Closed set, resolved 2026-09-03**: VM, word, block, and message are the complete set — "closed
+set, no new cards, naturally, subject to change." Not permanently frozen, but not open-ended
+by default either — a fifth card (e.g. a "console" dimension, given the D.2b pentagon names
+Console as a full peer node) would be a deliberate future decision, not something implicitly
+already on the table.
+
+**Word-ACL reconciliation resolved 2026-09-02.** Checked `capsules/ACL.4th` directly: both
+existing modes (`STRICT` — "always allow, TTL stays 0 (recheck always)"; `TTL` — "compute TTL
+from heat; set allow=1") already default to `allow=1` — no path in the current system denies
+by default, already matching the word card's "default-permissive baseline" almost exactly.
+Since each VM has its own dictionary (H.10), the existing per-word ACL state is already
+naturally scoped per-session, for free. **Confirmed: the word card is not a new parallel
+structure — it's the existing `acl_ttl`/`acl_allow`/`acl_mode`/`acl_pinned` system, wholesale,
+reused as-is.** The stack-of-cards framing is new vocabulary for what already exists, not a
+new mechanism.
+
+**The one genuinely new piece, not present in today's system at all**: creator-ceiling
+enforcement. Nothing today caps a newly-birthed VM's word-ACL state against its parent's.
+
+**Mechanism decided 2026-09-03, after a mid-conversation reversal.** First proposed: hook the
+ceiling check into the existing `ACL-RECHECK` cold path (checked later, no birth-time copy) —
+initially agreed, but this runs into a real problem: each VM has an entirely separate
+`DictEntry` dictionary (H.10), so `ACL-RECHECK` running inside a child would need a live
+cross-VM lookup back to the parent's own dictionary state, never designed. On seeing this, the
+user reconsidered: **"perhaps a fast copy might be cheaper and just as effective."**
+
+**Final: birth-time snapshot, no live sync, ever.** The child's `acl_allow`/`acl_mode`/
+`acl_pinned`/`acl_ttl` are copied from the parent once, at birth — no ongoing reference back
+to the parent afterward, which solves the cross-VM lookup problem outright. The child's own
+ACL state can still grow/shrink dynamically after birth (the word card's "additive/subtractive"
+framing still holds); it just starts from the snapshot rather than staying synced to the
+parent's *current* state. **Explicit rationale, user's own words**: "if something was
+developed with a particular set of ACLs, it should remain at that — otherwise parent changes
+break the child's program." Program stability for the child, not administrative convenience,
+is why live-sync was rejected.
+
+### H.4 — VM card
+
+Narrow by design: a single base gate ("who owns / can-touch this VM at all") that other, finer
+checks sit on top of. Does not itself enumerate operations (birth/kill, console attach,
+retarget, quota grant, etc.) — those are finer-grained checks built elsewhere.
+
+- **Zuse is entirely outside the card stack**: "forget Zeus [Zuse]. Zeus will always have 100
+  percent authority" — unconditional, not modeled as an always-allowed path *through* the VM
+  card the way the earlier `ACLKEY` pass (§F.2) had framed it. Zuse bypasses the card stack
+  entirely, full stop.
+- **Single owner, for now**: exactly one `owner_pubkey` per VM at this gate (match or no
+  match), not a list of authorized identities — "single owner for now," multi-owner
+  explicitly deferred, not in scope.
+- Matches the `VMIdentity{owner_pubkey[32], installed}` shape already decided in the earlier
+  `ACLKEY` pass (§F.2) — the VM card is effectively that ownership check, non-Zuse case only.
+
+### H.5 — Word card
+
+- **Default-permissive baseline**: "will have to pretty much admit any word" — not a
+  default-deny gate that has to explicitly enumerate everything.
+- **Dynamic, not fixed**: ACLs at this card are "additive/subtractive dynamic entities" — the
+  permission set can grow or shrink over the session's lifetime, not a static list decided
+  once at creation.
+- **Hard ceiling invariant**: "they can never exceed the creator's permissions" — a session's
+  word permissions can never exceed what its own creator/parent had. Delegation is capped by
+  the parent's own permission set — presumably where H.2's `parent` field earns its keep.
+- **Escape hatch, mechanism confirmed reused**: the only way to temporarily exceed that
+  creator-ceiling is "some kind of temporary Zuse power" — **confirmed reuse of the existing,
+  already-built-and-measured `ACL-TTL` mechanism** (`acl_ttl` field on `DictEntry`), not a new
+  parallel temporary-grant mechanism.
+- **Mechanism grounded, checked directly against `capsules/ACL.4th`**: the existing `ACL-TTL`
+  machinery is a recheck-cadence cache, not itself a grant mechanism — the real C-exposed
+  primitives are `ACL-ALLOW!`/`ACL-TTL!` (`ACL-RECHECK` recomputes TTL from execution heat and
+  sets `allow`). Reusing it for elevation means Zuse-triggered code calls these same
+  primitives directly, setting `allow=1` with a TTL that counts down to expiry.
+- **Trigger, decided 2026-09-02: live message-based request, kept deliberately simple.**
+  Three options were weighed — message-based request/grant, a live-console `sudo`-style
+  command, and a pre-signed capability ticket decoupling grant-time from use-time — user
+  picked the first: "live request, keep it simple for now." Rides the H.7 messaging protocol:
+  the requesting session posts a request (working name `ELEVATE-REQUEST`) on `common` or a
+  private topic with Zuse, Zuse's session responds grant/`NACK`, and the
+  `ACL-ALLOW!`/`ACL-TTL!` write happens on receipt. Fits the standing "nothing is done until
+  it's real Hermes messages" completion criterion (D.1). The other two options are explicitly
+  deferred, not rejected — "keep it simple for now" scopes this decision to the live-request
+  path only.
+- **Eligibility gate on top of the trigger, user-proposed**: "maybe zuse keeps a list of users
+  that can be granted zuse caps?" — confirmed as a gating layer, not a replacement for the
+  trigger. Zuse checks this list (keyed by `owner_pubkey`, matching H.4's single-owner
+  VM-card shape) before honoring any elevation request.
+- **Storage decided 2026-09-03**: persists across reboots, living in Zuse's already-built
+  growable metadata fence at the top of Artemis's block device (the same mechanism that
+  already persists Zuse's own `zuse_cert_devblock_t` identity — see Phase 8/Milestone 6).
+  Shape: a simple growable list of `owner_pubkey[32]` entries, no extra per-entry metadata —
+  "simple list, no extra metadata, unless we find a reason this won't work" (provisional
+  lean-by-default, not a permanent ban on adding fields later). Not yet designed: the actual
+  record format added to the metadata fence; how entries get added (presumably a Zuse-only
+  FORTH word, unbuilt); exact relationship to the still-unbuilt `MINT`-a-second-identity flow.
+
+### H.6 — Block card
+
+**Confirmed: reuses the already-decided `BMAPFMT` design** from §F.4 — distributed per-block
+ownership, not a new mechanism. Repurposes the dormant, fully-wired, zero-caller `blk_meta_t`
+struct: 8-byte owner-pubkey fingerprint + 1-byte fast-deny `acl_allow`, with deliberate
+reserved slack in the 40-byte block ("flexibility until we understand the recipe"). No
+separate centralized block-ownership table (makes `homeblocks_sig_t`'s reserved
+`blockmap_offset`/`blockmap_devblocks` fields unnecessary, already flagged for cleanup).
+
+**Extended 2026-09-02**: blocks need temporary elevation too, same `ACL-TTL`-reuse mechanism
+and Zuse-eligibility-list gating as the word card (H.5) — `acl_reserved` in §F.4's layout
+became a 4-byte `acl_ttl` (mirroring `DictEntry`'s countdown shape) plus 3 bytes still-open
+slack, kept lean rather than fully mirroring `DictEntry`'s `acl_mode`/`acl_pinned` too
+("lean, TTL only" — a block isn't "pinned"/"strict" the way a word is).
+
+**`flags` bit values decided 2026-09-02**: `blk_meta_t`'s existing `flags` field (`uint64_t`,
+doubling as block state) uses orthogonal bits, not a mutually-exclusive enum. Starting set:
+bit 0 = `CLAIMED`, bit 1 = `MIGRATING` (serves `MIGSM`), bit 2 = `STALE` (serves `UNCLEAN`),
+remaining 61 bits reserved.
+
+**FORTH-wrapper question decided 2026-09-02: yes.** Mirrors the word-level ACL split — raw C
+accessors (`BLK-ACL-ALLOW@`/`!`, `BLK-ACL-TTL@`/`!`, `BLK-OWNER@`), policy composed in FORTH on
+top. `zuse_cert_seed`'s C-only precedent doesn't apply — that's key material, block ACL fields
+are ordinary ACL state like `DictEntry`'s.
+
+`BMAPFMT`'s field/API design (TTL + flags bits + FORTH wrappers) is now fully complete but
+**the code change was never made** — this refactor is presumably where it finally lands.
+
+### H.7 — Messaging protocol: not groundwork, already real code (verified 2026-09-02)
+
+Originally captured as design vision — **upgraded 2026-09-02** after checking
+`capsules/common/messaging.4th` directly instead of assuming. The protocol described below
+isn't a future design, it's already substantially built:
+
+- **PubSub, decided.** Terminology is **"topics"** — the existing code's own term is
+  "channel"/`CH`. **Resolved: `CH` already *is* the topic, 1:1, no new representation
+  needed** — "topic" is just today's newly-adopted vocabulary for what the code already calls
+  a channel.
+- **Every VM always subscribes to one well-known "common" topic.** Real: `COMMON-CH`, the
+  actual variable holding the one canonical common channel, owned by Hermes and wired into
+  `hermes/init.4th` at boot (`CH-ADD-MBR` adds members 0 and 1).
+- **Handshake flow, real functions**: `CH-REQUEST ( type from to paddr plen -- )` — checks
+  `COMMON-CH` is `CH-OPEN`, sends via `MSG-SEND` — is literally "post a message on `common`
+  requesting a commune." `CH-ACCEPT ( -- ch|0 )` — the receiving side allocates a new private
+  channel, marks it `CH-NEGOTIATING`. `CH-CONFIRM ( ch -- )` transitions
+  `CH-NEGOTIATING` → `CH-OPEN`. `CH-CLOSE ( ch -- )` tears a channel down (`CH-CLOSING`).
+- **ACK/NACK, real**: `MSG-ACK-LAST`/`MSG-NACK-LAST`/`MSG-NACKED` (253) — "purely local, no
+  VM-EXEC indirection" per the code's own comment — a general reliability mechanism applied to
+  every message on any topic, not specific to the handshake step.
+
+### H.8 — Message card
+
+**Scope confirmed narrow and one-sided**: gates only "who's allowed to post on `common`
+requesting a commune" — the *initiating* side of the H.7 handshake, i.e. who's allowed to
+call the real `CH-REQUEST` function above. The receiving VM's decision to accept/ACK (i.e.
+`CH-ACCEPT`) is **not** gated by this card.
+
+**Private-topic traffic gating, resolved 2026-09-02**: checked `MSG-SEND`
+(`capsules/common/messaging.4th:213`, the underlying primitive both `CH-REQUEST` and any
+private-topic traffic use) directly — no ACL check anywhere in it today, purely mechanical.
+**Confirmed: private-topic traffic stays ungated.** Trust is established once at the
+handshake, and nothing re-checks permission on every subsequent message within an
+already-open private topic — consistent with this card's own narrow scope and the elevation
+trigger's "keep it simple for now."
+
+**The message card's full, final scope**: gates only the single call to `CH-REQUEST`.
+Nothing else in the messaging path is ACL-gated by design.
+
+**Implementation-gap note (2026-09-02)**: since `CH-REQUEST` is real, already-callable code
+with no ACL gate in front of it today, this card's job is a concrete, well-targeted wiring
+task — add the gate check to the real function — rather than a hypothetical one waiting on
+future messaging infrastructure. Not yet built.
+
+### H.9 — Gap analysis (as of 2026-09-02)
+
+Explicitly open items surfaced during this capture pass, none decided yet:
+
+1. **CLOSED 2026-09-02 — non-pinned session mapping (H.1).** Yes — an ephemeral user VM's
+   session lands as a non-pinned, `COOL`-subject Stadium patron, thumbdrive detach as the
+   explicit trigger (synthesized from D.2's earlier finding). No exception case for a
+   temporarily-pinned user VM.
+2. **CLOSED 2026-09-02 — `parent` and `name` session fields (H.2).** Confirmed as-is, no
+   adjustment. All five session fields now confirmed (still subject to the general
+   "revisiting... around and around" caveat, but no longer an open gap specifically).
+3. **CLOSED 2026-09-02 — word-level ACL reconciliation (H.3).** The word card *is* the
+   existing `acl_ttl`/`acl_allow`/`acl_mode`/`acl_pinned` system, wholesale, no new parallel
+   structure. New follow-on gap surfaced by this closure: creator-ceiling enforcement at VM
+   birth time isn't designed anywhere yet (nothing today caps a child's word-ACL state against
+   its parent's).
+4. **CLOSED 2026-09-02 — temporary-elevation invocation path (H.5).** Trigger decided: a live
+   message-based request (`ELEVATE-REQUEST` on `common` or a private topic, Zuse's session
+   grants/`NACK`s, write happens on receipt via `ACL-ALLOW!`/`ACL-TTL!`), gated by a
+   Zuse-held eligibility list keyed by `owner_pubkey`. Still open underneath this closure: the
+   eligibility list's exact representation/storage, and the two explicitly-deferred (not
+   rejected) alternate triggers — live-console `sudo`-style grant, and pre-signed capability
+   tickets.
+5. **`BMAPFMT` code change (H.6).** Field design was finished in the §F.4 pass but the actual
+   code edit to `blk_meta_t` was never made — a real, concrete implementation gap, not just an
+   open question.
+6. **CLOSED 2026-09-02 — topic/`CH` reconciliation (H.7).** `CH` already *is* the topic, 1:1.
+   Bigger than expected: this check also upgraded all of H.7/H.8 from "protocol vision" to
+   "already real code" (`COMMON-CH`, `CH-REQUEST`, `CH-ACCEPT`, `CH-CONFIRM`, `CH-CLOSE`,
+   `MSG-ACK-LAST`/`MSG-NACK-LAST` all exist and work today in `capsules/common/messaging.4th`).
+   The message card's gate is now a concrete wiring task onto a real function, not a
+   hypothetical one waiting on future infrastructure.
+7. **CLOSED 2026-09-02 — private-topic traffic gating (H.8).** Confirmed ungated — `MSG-SEND`
+   has no ACL check today; trust is established once at the handshake, nothing re-checks
+   permission afterward. The message card's scope is now final: it gates `CH-REQUEST` alone.
+8. **CLOSED 2026-09-02 — the `EXPIRE`/D.2 relationship.** No conflict — D.2 is a special case
+   of H.1, fully subsumed (D.2 describes the non-pinned branch specifically; pinned sessions
+   have no D.2-style "ending" at all).
+9. **Every other card beyond the four named** (VM, word, block, message) — the model list is
+   confirmed as the *named-so-far* set, not stated as closed/exhaustive.
+10. **No implementation has started.** Every item above, and every card definition in
+    H.4–H.8, is design capture only — no struct has been written, no `stadium_birth_hermes()`/
+    `_artemis()` exists, no `Session` header exists. Standard for this document's own
+    discipline (see D's intro), but worth stating plainly given the size of this section.
+
+### H.10 — Verification pass: "are we painting ourselves into a corner?" (2026-09-02)
+
+Asked directly by Captain Bob. One load-bearing assumption underneath H.3/H.5 got checked
+against the live code rather than left as an inference.
+
+**The risk**: the word card's creator-ceiling invariant and the H.5 elevation trigger both
+live on `DictEntry` (`acl_allow`/`acl_ttl`), which only works per-session if each VM has its
+own separate dictionary — a shared/global dictionary would make a single `acl_allow` bit
+unable to mean "yes for session A, no for session B" on the same word.
+
+**Verified true, no conflict, no redesign needed.** `struct VM` (`include/vm.h:410-412`) owns
+its own `uint8_t* memory` buffer and its own `DictEntry* latest` chain; `vm_bootstrap.c:181`
+(`vm->memory = (uint8_t*)vm_host_alloc(vm, VM_MEMORY_SIZE, ...)`) allocates a fresh,
+independent memory/dictionary buffer on every VM birth. Hera, Hermes, Artemis, and any future
+child each get their own separate dictionary — `DictEntry` ACL fields are already naturally
+scoped per-session. H.3's stack-of-cards model and H.5's word card/elevation trigger stand as
+decided, unchanged by this check.
+
+Two smaller, lower-risk items flagged in the same pass:
+- **CLOSED 2026-09-02 — pin-authority choke point (H.2).** Session.pinned is authoritative
+  over Stadium's `STADIUM_FLAG_PIN` bit. Decided: **full choke point at the session level,
+  both directions** — both writing and reading pin state go exclusively through session-owned
+  functions (e.g. `session_set_pinned()` / `session_is_pinned()`); nothing, including existing
+  Stadium code, reads `STADIUM_FLAG_PIN` directly off the patron header anymore. Session is
+  the sole authority for both write and read, not just the write path.
+- **Elevation trigger, updated 2026-09-02: closer to usable than first thought.** Rides Hermes
+  messaging — at the time this risk was flagged, assumed to not be the real implementation
+  yet. §H.7's later verification found the messaging substrate (`CH-REQUEST`/`CH-ACCEPT`/
+  `CH-CONFIRM`/ACK-NACK) is already real, working code. What's still missing is only the ACL
+  gate itself (H.8) and the `ELEVATE-REQUEST` message type/handler — smaller gaps than
+  originally flagged, not a missing substrate.
+
+### H.11 — Gap analysis, refreshed (2026-09-02, end of session)
+
+Full sweep across the whole design pass, not just a re-list of §H.9's original ten items — 7
+of them are now closed (1, 2, 3, 4, 6, 7, 8). New sub-gaps surfaced while closing the old
+ones. This supersedes §H.9 as the current accurate picture; §H.9 itself is left intact above
+as historical record (each item already carries its own closure annotation inline).
+
+**Genuinely open design question (never asked):**
+1. **CLOSED 2026-09-03.** Closed set — VM, word, block, message are the complete four, no new
+   cards for now (see H.3).
+
+**Small design pieces, now resolved 2026-09-03:**
+2. **CLOSED.** Creator-ceiling enforcement (§H.3) is a birth-time snapshot copy, not a live
+   `ACL-RECHECK`-time check — decided after a mid-conversation reversal once the live-check
+   approach's cross-VM lookup problem surfaced.
+3. **CLOSED.** Zuse's eligibility list persists in the existing metadata-fence mechanism, as a
+   simple `owner_pubkey[32]` list, no extra metadata (§H.5).
+
+**Pure implementation gaps — design fully decided, nothing coded yet:**
+4. `stadium_birth_hermes()`/`_artemis()` don't exist (§H.1).
+5. The `Session` struct + its own header don't exist (§H.2).
+6. `BMAPFMT`'s code edit to `block_subsystem.h`/`.c` (§F.4/§H.6 — field/API design fully
+   closed).
+7. The message card's ACL gate isn't wired onto the real `CH-REQUEST` (§H.8).
+8. Creator-ceiling enforcement itself — the birth-time copy logic (§H.3, design now fully
+   decided as of item 2's closure above, code not written).
+9. The eligibility-list's actual metadata-fence record format + the Zuse-only FORTH word to
+   add entries (§H.5, design now fully decided as of item 3's closure above, code not
+   written).
+
+**Explicitly deferred, not rejected (intentional non-goals for now):**
+10. VM card multi-owner support (§H.4).
+11. Elevation trigger alternates — live-console `sudo` path, pre-signed capability tickets
+    (§H.5).
+
+**Remaining genuinely open design question, after this pass**: none — every design-level
+question from this list is now closed. What's left is implementation (items 4–9) and
+intentional deferrals (10–11).
+
+### H.12 — Implementation punch list (2026-09-03)
+
+One coding task per item, not a concept per item — each followed by the mandatory
+amd64/aarch64/riscv64 boot acceptance test (this document's only valid acceptance criterion,
+see the top-level CLAUDE.md). Grounded against live code, not the earlier design captures'
+assumptions — two corrections surfaced while building this list, both noted inline below.
+
+**Correction 1**: `stadium_birth_hermes()`/`_artemis()` (§H.11 item 4) don't need writing from
+scratch. `capsule_birth.c`'s generic admission path (~lines 574–602, used for every VM birth
+today) already admits every born VM as a Stadium patron — it's just hardcoded to admit them
+**unpinned** (`vm_patron.flags = 0`, with a comment explicitly noting "unpinned... unlike
+Hera"). The real task is making that existing path pin Hera/Hermes/Artemis specifically,
+leaving ordinary/user VMs unpinned as they already correctly are.
+
+**Correction 2**: `VMIdentity` (`include/starkernel/vm_identity.h`) already exists, fully
+built — `owner_pubkey[32]` + `installed` + `acl_caps` (capability bitmask), the VM-card shape
+from H.4, plus more. `Session.identity` should be a `VMIdentity`, not a new type. Its own doc
+comment confirms Hera/Hermes/Artemis have no installed identity yet ("before D.5's per-VM-
+identity work lands") — wiring real identities into them is part of this refactor's remaining
+work, not new invention.
+
+**Phase 1 — Session struct + pin-authority choke point**
+- [x] **1. DONE 2026-09-03.** `include/starkernel/session.h`: `Session{vm_id (VMUuid), pinned
+  (int), parent (VMUuid), name (fixed buffer, `SESSION_NAME_BUF`=64), identity (VMIdentity,
+  embedded)}`. Type only, no logic. No callers yet, so this acceptance run only confirms the
+  header itself is syntactically clean and doesn't break the build. Verified 3-arch boot to
+  `ok>` (amd64/aarch64/riscv64).
+- [x] **2. DONE 2026-09-03, one deviation from the original wording.**
+  `src/starkernel/vm/session.c` + `session_boot_init()`/`session_find(VMUuid)`/
+  `session_register(...)`. Not a fixed-size array as originally written here — found
+  `stadium.c`'s own `StadiumVMQuota` table had already been moved off a fixed array to a
+  `kmalloc`'d-at-boot, budget-sized one (same "population isn't knowable in advance"
+  reasoning), so `session.c` mirrors that current precedent instead: `session_boot_init()`
+  sizes the slot table from `stadium_max_vm_count()`, must run after `stadium_boot_init()`.
+  Added `session.c` to `Makefile.starkernel`'s explicit `LOADER_EXTRA_SRCS`/
+  `KERNEL_EXTRA_SRCS` list (not a wildcard build). No callers yet. Verified 3-arch boot to
+  `ok>`.
+- [x] **3. DONE 2026-09-03, one addition found necessary.** `session_set_pinned()`/
+  `session_is_pinned()` implemented — the pin-authority choke point (H.2/H.10).
+  `session_is_pinned()` answers from `Session.pinned` directly (the authoritative copy, no
+  Stadium re-derivation); `session_set_pinned()` writes both `Session.pinned` and the
+  mirrored `STADIUM_FLAG_PIN` bit on the session's own patron header, so Stadium's own
+  internal eviction/admission logic (which must stay self-contained, no call back into
+  session.c) keeps seeing a correct bit. **Addition**: `Session` needed a `stadium_cell`
+  field (index into `stadium_cells()`) that wasn't in the original §H.2 field list — the
+  choke point can't reach the right patron header without it. Necessary plumbing, not a new
+  session-level concept, so not treated as reopening §H.2's design. Also moved
+  `STADIUM_FLAG_PIN`'s `#define` from a `stadium.c`-private constant to `stadium.h` (public)
+  so `session.c` can reference it without duplicating the definition. Verified 3-arch boot to
+  `ok>`.
+- [x] **4. DONE 2026-09-03.** Rewired `stadium_birth_hera()` to admit unpinned then register
+  through `session_register(vm_uuid_hera(), vm_uuid_hera(), "Hera")` (self-referential
+  parent, matching `capsule_run.h`'s `parent_vm_id == vm_id` root convention) +
+  `session_set_pinned(vm_uuid_hera(), 1)` — Hera is session zero. `stadium_admit()` confirmed
+  to have no admission-time-special pin handling (just copies the candidate header), so
+  admit-unpinned-then-pin-after is safe. Soft-fail (logged, non-fatal) if `session_register()`
+  fails — Hera's actual Stadium admission already succeeded and is what the patron-zero
+  invariant is about. Wired `session_boot_init()` into `kernel_main.c` right after
+  `stadium_boot_init()`, before `stadium_birth_hera()`. Verified 3-arch boot to `ok>`, no
+  soft-fail message logged on any arch (registration succeeded), Hermes/Artemis births
+  unaffected.
+
+**Phase 2 — Pin Hermes/Artemis (Correction 1 above)**
+- [x] **5. DONE 2026-09-03, one bug found and fixed via probe.** `capsule_birth.c`'s generic
+  admission block now registers a session for every born VM and pins it if
+  `is_fleet_foundation` (Hera/Hermes/Artemis). Admits unpinned then pins after, same ordering
+  as step 4 (`stadium_admit()` confirmed to have no admission-time pin handling). **Bug found
+  by step 6's probe**: the fleet-foundation name check first used
+  `vm_name_eq_nocase(capsule_name, "Hermes")`, exact match — but `capsule_name` is actually
+  `"hermes:init.4th"`/`"artemis:init.4th"` (the real "namespace:filename" convention), never
+  a bare name, so the check silently never matched. Fixed with a new
+  `vm_name_prefix_eq_nocase()` helper matching everything before a literal `:`. Parent is
+  hardcoded to `vm_uuid_hera()` for now (every birth through this path is Hera-initiated
+  today) — step 7 generalizes this to the actual birthing VM's own id.
+- [x] **6. DONE 2026-09-03.** Confirmed via a temporary probe (`console_println` after
+  `session_set_pinned()`, captured once then reverted per this project's probe convention):
+  first run showed `hermes:init.4th pinned=0` / `artemis:init.4th pinned=0` (the bug above),
+  second run after the fix showed `pinned=1` for both. Probe code fully reverted before
+  commit — only its finding (the `:`-suffixed capsule-name format) remains, in step 5's doc
+  comment and this entry.
+
+**Phase 3 — Session fields wired at birth**
+- [x] **7. DONE 2026-09-03, larger than one line — a real signature-threading pass.**
+  `Session.parent` now comes from the actual birthing VM's own `stadium_vm_id`, not a
+  hardcoded `vm_uuid_hera()`. This meant adding a `VMUuid parent` parameter to
+  `capsule_birth_baby()` and, one level up, to `capsule_console_birth()` and
+  `capsule_runcap_birth()` (neither had a `VM *` in their own signature, but every one of
+  their callers did) — traced all 6 real call sites across `mama_forth_words.c` (4: `BIRTH`,
+  `CAPSULE-BIRTH`, `CONNECT-ARTEMIS`, `CONNECT-HERMES`, plus `RUNCAP-TEST`/`PAIR-TEST` = 6
+  total) and `capsule_wirebind.c` (2: console + user birth in
+  `capsule_wirebind_try_attach()`), confirmed each has a real `VM *` (`vm`/`mama_vm`) in
+  scope, and passed `vm->stadium_vm_id` through at every one. Two functions
+  (`mama_word_connect_artemis`/`_hermes`) had their `vm` parameter marked
+  `__attribute__((unused))`, now genuinely used — attribute removed. User explicitly chose
+  this option (full threading) over leaving the earlier `vm_uuid_hera()` hardcode in place.
+- [x] **8. Already satisfied by step 5.** `session_register(vm_id, parent, capsule_name)`
+  already passes the capsule's own name string — nothing further needed.
+- [x] **9. Confirmed by code inspection.** `session_register()` (step 2) zeroes `identity`
+  unconditionally — `installed` reads 0 by construction, matching `VMIdentity`'s own
+  documented default. No behavior change, as expected.
+
+  Verified 3-arch boot to `ok>` (amd64/aarch64/riscv64) for step 7's actual code changes,
+  which also exercises 8 and 9 unchanged.
+
+**Phase 4 — Creator-ceiling enforcement (H.3, birth-time snapshot)**
+- [x] **10. DONE 2026-09-03.** `dictionary_snapshot_acl_from_parent(child, parent)` added as a
+  static helper in `capsule_birth.c`: walks `child->latest`'s link chain, looks up each name
+  in `parent` via `vm_find_word()` (the same C-level lookup `FIND` itself uses — not a
+  modification to `FIND`, per the standing "never modify `FIND`" rule), copies
+  `acl_allow`/`acl_mode`/`acl_pinned`/`acl_ttl` onto the child's matching entry when found.
+  Baby-specific words the parent doesn't have are left untouched — nothing to cap them
+  against.
+- [x] **11. DONE 2026-09-03.** Called once via `vm_find_entry_ptr(parent)` (the same internal
+  registry lookup `capsule_birth_mama()` already uses for Hera's own entry) to get the
+  parent's live `VM*`, right after `dict_hash`/parity logging — deliberately *after*, not
+  before: the snapshot depends on the parent's *current* ACL state, which can vary run-to-run
+  once Zuse-granted elevations exist, so applying it before the hash would make
+  `birth_dict_hash` no longer a pure function of capsule content, breaking the "same capsule
+  booted twice produces the same dict hash" determinism invariant this codebase relies on
+  elsewhere. Verified 3-arch boot to `ok>` (amd64/aarch64/riscv64).
+
+**Phase 5 — `BMAPFMT` (§F.4/§H.6, independent, can run any time)**
+- [x] **12. DONE 2026-09-03, one pre-existing bug found along the way.** `blk_meta_t`'s old
+  40-byte `owner_id`/`permissions`/`acl_block`/`signature[2]` replaced with
+  `owner_fp[8]`/`acl_allow`/`acl_ttl` (u32)/`acl_reserved[3]`/`reserved_future`, matching
+  §F.4/§H.6's decided layout exactly. **Verified via a real standalone `offsetof`/`sizeof`
+  compile, not hand math**, per this step's own instruction: found `sizeof(blk_meta_t)` was
+  already **344**, not the `341` its own `BLK_META_PER_BLOCK` constant and "341-byte slice"
+  comment claimed — a pre-existing inaccuracy, not introduced by this edit (ordinary trailing
+  struct-alignment padding after the final `uint8_t padding[5]`). Harmless in practice:
+  `BLK_META_PER_BLOCK` has **zero callers anywhere in the codebase**, consistent with
+  `blk_meta_t` itself being dormant. After this edit's own alignment changes (a `uint32_t`
+  and a `uint64_t` field each force a few bytes of compiler-inserted padding after preceding
+  `uint8_t` fields), the real new size is **336** bytes (8 smaller than before, not the
+  "same 40-byte budget" framing implied — natural alignment, not a bug). Added a
+  `_Static_assert(sizeof(blk_meta_t) == 336, ...)`, matching `blk_volume_meta_t`'s own
+  existing precedent in this same file, and fixed the now-doubly-stale "341-byte slice"
+  comment to point at the assert instead of repeating the wrong number. Did not touch
+  `BLK_META_PER_BLOCK` itself — out of scope, unused, not what this step asked for.
+  Verified 3-arch boot to `ok>` (amd64/aarch64/riscv64).
+- [x] **13. DONE 2026-09-03.** `BLK_FLAG_CLAIMED`/`BLK_FLAG_MIGRATING`/`BLK_FLAG_STALE`
+  (bits 0/1/2, `1ull << n`) defined in `block_subsystem.h` right above `blk_meta_t`, `flags`
+  field comment updated to point at them. Verified 3-arch boot to `ok>`
+  (amd64/aarch64/riscv64).
+- [x] **14. DONE 2026-09-03.** `blk_owner_fp_get`/`_set`, `blk_acl_allow_get`/`_set`,
+  `blk_acl_ttl_get`/`_set`, `blk_flags_get`/`_set` added — thin read-modify-write wrappers
+  over the existing `blk_get_meta()`/`blk_set_meta()` (which already own caching/dirty-
+  tracking; these add no new state). FORTH wrappers (step 15) call these, not
+  `blk_get_meta()`/`blk_set_meta()` directly, mirroring the word-level ACL system's own
+  C-primitive/FORTH-policy split. Verified 3-arch boot to `ok>` (amd64/aarch64/riscv64).
+- [x] **15. DONE 2026-09-03, live-tested.** `BLK-ACL-ALLOW@`/`!`, `BLK-ACL-TTL@`/`!`,
+  `BLK-OWNER@` registered in `block_words.c` (shared/vendored source — verified with both a
+  hosted sanity build and the 3-arch kernel boot). `BLK-OWNER@` packs the 8-byte fingerprint
+  into one cell (`cell_t` is `int64_t`, 8 bytes — exact fit, raw bit reinterpretation). No
+  `BLK-OWNER!` — only the five words step 15 itself listed; setting ownership stays a
+  controlled, C-only operation (MINT/birth), not a general FORTH write. **Live-tested via QMP
+  keystrokes on the running riscv64 instance**: `1 BLK-ACL-ALLOW@` executed cleanly (`ok`, no
+  `UNKNOWN WORD` error) against a real block. Verified 3-arch boot to `ok>`
+  (amd64/aarch64/riscv64).
+- [x] **16. DONE 2026-09-03, live-tested — Phase 5 complete.** `capsules/block-acl.4th`
+  (blocks 4019–4020, next free range after `zuse.4th`'s 4016–4018, verified against
+  `BLOCK_MAP.md` — CLAUDE.md's block-namespace rule) defines `BLK-ACL-CHECK ( block# --
+  allow? )`: a real, working fast-deny check mirroring `vm.c:611-624`'s pattern applied to a
+  block instead of a word. First touch lazily claims the block (`allow=1`,
+  `TTL=BLK-ACL-BASE-TTL`=256, same base value as `ACL.4th`'s own), matching the word card's
+  default-permissive baseline — not a stub, genuinely does something on every call. No
+  automatic TTL-decrement hot path exists for blocks yet (words decrement per-dispatch in
+  `vm.c`; blocks have no equivalent loop) — out of this step's scope, the fast-deny gate
+  itself is real and complete regardless. Passed `mkcapsule --lint` cleanly. Loaded via a new
+  `S" block-acl.4th" EXEC` line in `init.4th`'s Block 2049, right after `ACL.4th`'s own —
+  confirmed `ACL.4th`'s own activation messages identical before/after this addition (nothing
+  broken). **Live-tested via QMP keystrokes**: `1 BLK-ACL-CHECK` executed cleanly (`ok`, no
+  `UNKNOWN WORD`) on the running amd64 instance. Verified 3-arch boot to `ok>`
+  (amd64/aarch64/riscv64).
+
+  **Phase 5 (`BMAPFMT`) is now fully complete** — field layout, `flags` bits, C accessors,
+  FORTH wrappers, and a real policy word all landed and verified.
+
+**Phase 6 — Zuse eligibility list (H.5)**
+- [ ] **17.** Extend the metadata-fence record format with a new growable
+  `owner_pubkey[32]`-list record type.
+- [ ] **18.** Implement read/add/membership-check functions in C.
+- [ ] **19.** Add a Zuse-only FORTH word to add an entry, gated by `zuse_session`.
+
+**Phase 7 — Message card gate + `ELEVATE-REQUEST` (H.8)**
+- [ ] **20.** Add the initiator-only ACL gate at `CH-REQUEST`'s entry point
+  (default-permissive baseline, real hook point established).
+- [ ] **21.** Define `ELEVATE-REQUEST` and a minimal real handler checking the eligibility
+  list, granting via `ACL-ALLOW!`/`ACL-TTL!` on match.
+- [ ] **22.** Add the FORTH entrypoint a session actually calls to send one.
+
+**Excluded, per H.11's deferred items 10–11**: VM card multi-owner support, live-console
+`sudo`-style elevation, pre-signed capability tickets.

Makefile.starkernel

@@ -528,7 +528,8 @@ LOADER_EXTRA_SRCS := \
     $(KERNEL_SRC)/vm/q48_stubs.c \
     $(KERNEL_SRC)/vm/stadium.c \
     $(KERNEL_SRC)/vm/stadium_words.c \
-    $(KERNEL_SRC)/vm/stadium_blocks.c
+    $(KERNEL_SRC)/vm/stadium_blocks.c \
+    $(KERNEL_SRC)/vm/session.c
 
 KERNEL_EXTRA_SRCS := $(LOADER_EXTRA_SRCS)
 

capsules/BLOCK_MAP.md

@@ -1,6 +1,5 @@
 # Capsule Block Manifest — Auto-generated
-
+<!-- Generated by mkcapsule --manifest  2026-09-03T11:42:42Z -->
-<!-- Generated by mkcapsule --manifest  2026-08-30T08:47:40Z -->
 <!-- DO NOT EDIT — re-run mkcapsule --manifest to refresh.  -->
 <!-- Hand-written justifications and immutability notes live  -->
 <!-- in MANIFEST.md alongside this auto-generated index.      -->
@@ -11,6 +10,7 @@
 |---------|----------------|----------|--------|
 | `ACL.4th` | 4000, 4001, 4002, 4003, 4004, 4005, 4006, 4007, 4015 | `0xd781d22148ff171d` | yes |
 | `artemis:init.4th` | 4110, 4111, 4112, 4113, 4122, 4123, 4124, 4125, 4126, 4127, 4128, 4129, 4130, 4131, 4132, 4133, 4134, 4135, 4136, 4137, 4138, 4139, 4140, 4141, 4160, 4161, 4162, 4163, 4164, 4165, 4166, 4167, 4168, 4169, 4170, 4171, 4172, 4173, 4174, 4177, 4178, 4179, 4180, 4181, 4182, 4851, 4852, 4853, 4854 | `0xfe6e570467368153` | yes |
+| `block-acl.4th` | 4019, 4020 | `0xf5eab0544b962dfa` | yes |
 | `common:messaging.4th` | 5003, 5004, 5005, 5006, 5007, 5008, 5009, 5010, 5011, 5012, 5013, 5014, 5015, 5016, 5017, 5018, 5019, 5020, 5021, 5022, 5023, 5024, 5025, 5026, 5027, 5028, 5029, 5030, 5031, 5032, 5033, 5034, 5035, 5036, 5037, 5038 | `0x892fd1c86d8c175e` | yes |
 | `common:msg.4th` | 4055 | `0x850a0382344ea6c4` | yes |
 | `doe-campaign.4th` | 4060, 4061, 4062, 4063, 4064, 4065 | `0x3d4549142d91ec20` | yes |
@@ -34,7 +34,7 @@
 | `init-l8-temporal.4th` | 4830, 4831 | `0x51abd4c138246651` | yes |
 | `init-l8-transition.4th` | 4840, 4841, 4842 | `0xbcc1a81976f0a4c9` | yes |
 | `init-l8-volatile.4th` | 4810, 4811, 4812, 4813 | `0x98caabbbd92abac4` | yes |
-| `init.4th` | 2049, 2050, 2057 | `0x9ac6523d24b80cd0` | yes |
+| `init.4th` | 2049, 2050, 2057 | `0xa94a7b63db15021b` | yes |
 | `lib.4th` | 4050 | `0x4b216635c359ef73` | yes |
 | `process.4th` | 4300, 4301 | `0x781afc1dbd0294f7` | yes |
 | `sdk.4th` | 5109, 5110, 5111, 5112, 5113, 5114, 5115 | `0x008fdbbb62c94a3a` | yes |
@@ -46,9 +46,9 @@
 
 | LBN | Capsule | xxHash64 | Status |
 |-----|---------|----------|--------|
-| 2049 | `init.4th` | `0x9ac6523d24b80cd0` | ok |
+| 2049 | `init.4th` | `0xa94a7b63db15021b` | ok |
-| 2050 | `init.4th` | `0x9ac6523d24b80cd0` | ok |
+| 2050 | `init.4th` | `0xa94a7b63db15021b` | ok |
-| 2057 | `init.4th` | `0x9ac6523d24b80cd0` | ok |
+| 2057 | `init.4th` | `0xa94a7b63db15021b` | ok |
 | 2064 | `init-l8-omni.4th` | `0x5979e314d6452045` | ok |
 | 2065 | `init-l8-omni.4th` | `0x5979e314d6452045` | ok |
 | 2066 | `init-l8-omni.4th` | `0x5979e314d6452045` | ok |
@@ -108,6 +108,8 @@
 | 4016 | `zuse.4th` | `0x490ded9be257a90b` | ok |
 | 4017 | `zuse.4th` | `0x490ded9be257a90b` | ok |
 | 4018 | `zuse.4th` | `0x490ded9be257a90b` | ok |
+| 4019 | `block-acl.4th` | `0xf5eab0544b962dfa` | ok |
+| 4020 | `block-acl.4th` | `0xf5eab0544b962dfa` | ok |
 | 4050 | `lib.4th` | `0x4b216635c359ef73` | ok |
 | 4055 | `common:msg.4th` | `0x850a0382344ea6c4` | ok |
 | 4060 | `doe-campaign.4th` | `0x3d4549142d91ec20` | ok |
@@ -354,4 +356,4 @@
 None.
 
 ---
-*32 capsule(s) scanned.  Re-run `mkcapsule --manifest <dir>` to refresh.*
+*33 capsule(s) scanned.  Re-run `mkcapsule --manifest <dir>` to refresh.*

capsules/block-acl.4th

@@ -0,0 +1,25 @@
+Block 4019
+( block-acl.4th - Block-Level Access Control  BMAPFMT )
+( C prims: BLK-ACL-ALLOW@ BLK-ACL-ALLOW! BLK-ACL-TTL@ )
+( BLK-ACL-TTL! BLK-OWNER@ )
+( Policy words this file: BLK-ACL-CHECK )
+( Mirrors ACL.4th's C-primitive/FORTH-policy split, )
+( applied to blocks instead of words. )
+( FABRIC-3.md H.12 step 16, 2026-09-03. )
+256 CONSTANT BLK-ACL-BASE-TTL
+
+Block 4020
+( BLK-ACL-CHECK  block# -- allow?                     )
+( Fast-deny check, vm.c 611-624's pattern applied to  )
+( a block. First touch: default-permissive claim --   )
+( allow=1, TTL=BLK-ACL-BASE-TTL -- matching the word  )
+( card's own default. No automatic TTL decrement loop )
+( exists for blocks yet -- words decrement per word   )
+( dispatch, blocks have no equivalent hot path -- but )
+( this is a real, working fast-deny gate either way.  )
+: BLK-ACL-CHECK ( block# -- allow? )
+  DUP BLK-ACL-TTL@ 0= IF
+    DUP BLK-ACL-BASE-TTL SWAP BLK-ACL-TTL!
+    DUP 1 SWAP BLK-ACL-ALLOW!
+  THEN
+  BLK-ACL-ALLOW@ ;

capsules/init.4th

@@ -14,6 +14,7 @@ Block 2049
 : VM-PARENT   ( -- id ) 0 ;
 : VM-CHILDREN ( -- ) ." (none)" CR ;
 S" ACL.4th" EXEC
+S" block-acl.4th" EXEC
 S" lib.4th" EXEC
 S" fabric.4th" EXEC
 S" font.4th" EXEC

include/block_subsystem.h

@@ -199,6 +199,16 @@ typedef struct {
 _Static_assert(sizeof(blk_volume_meta_t) == 4096,
                "blk_volume_meta_t must be exactly one 4 KiB devblock");
 
+/* blk_meta_t.flags bit values -- FABRIC-3.md §F.4/§H.6/§H.12 step 13,
+ * decided 2026-09-02/03. Orthogonal bits, not a mutually-exclusive enum:
+ * a block can be both CLAIMED and MIGRATING at once. Grounded in the only
+ * states §F.4 actually motivated by a real need (MIGSM/UNCLEAN, two
+ * then-currently-blocked graph nodes) plus CLAIMED/STALE, the names
+ * already used loosely in that pass's own prose. 61 bits remain reserved. */
+#define BLK_FLAG_CLAIMED   (1ull << 0) /* owned, per BMAPFMT's owner_fp */
+#define BLK_FLAG_MIGRATING (1ull << 1) /* mid-migration; serves MIGSM */
+#define BLK_FLAG_STALE     (1ull << 2) /* interrupted flush; serves UNCLEAN */
+
 /* Per-1 KiB block metadata (packed into top 1 KiB region of each 4 KiB sector). */
 typedef struct {
     /* Core integrity (16 bytes) */
@@ -210,7 +220,7 @@ typedef struct {
     uint64_t modified_time; /* Unix timestamp (last write) */
 
     /* Block status (16 bytes) */
-    uint64_t flags; /* Status flags */
+    uint64_t flags; /* Status flags -- BLK_FLAG_* bits above */
     uint64_t write_count; /* Number of writes (wear leveling) */
 
     /* Content identification (32 bytes) */
@@ -223,11 +233,37 @@ typedef struct {
     uint64_t entropy[4]; /* 256-bit entropy/random seed */
     uint64_t hash[4]; /* SHA-256 (optional) */
 
-    /* Security & ownership (40 bytes) */
+    /* Security & ownership -- FABRIC-3.md §F.4/§H.6/§H.12 step 12, decided
-    uint64_t owner_id; /* User/process ID */
+     * 2026-08-27/2026-09-03: BMAPFMT repurposes this slot rather than
-    uint64_t permissions; /* rwx-style permissions */
+     * building a separate on-drive block-map table (distributed
-    uint64_t acl_block; /* Block number containing ACL (0=none) */
+     * ownership/ACL, travels with the block itself). Replaces the old
-    uint64_t signature[2]; /* 128-bit signature */
+     * owner_id/permissions/acl_block/signature[2] fields, which predated
+     * and directly conflicted with both the anti-POSIX principle and
+     * VMIdentity's pubkey-based model. Not the same 40-byte budget the
+     * old fields occupied -- natural alignment padding (uint32_t acl_ttl
+     * and uint64_t reserved_future each force a few bytes of compiler-
+     * inserted padding after the preceding uint8_t fields) makes this
+     * section's real footprint smaller; verified below via
+     * _Static_assert on the whole struct's actual sizeof(), not trusted
+     * by hand (see the blk_volume_meta_t padding-bug lesson this project
+     * already learned once). */
+    uint8_t  owner_fp[8];     /* truncated fingerprint of owner's VMIdentity
+                                * pubkey -- cheap per-block; full pubkey
+                                * resolves via the drive's own identity
+                                * record. */
+    uint8_t  acl_allow;       /* cached fast-deny bit, checked first --
+                                * vm.c:611-624's exact pattern, applied to a
+                                * block instead of a word. */
+    uint32_t acl_ttl;         /* countdown, same shape as DictEntry's
+                                * acl_ttl -- blocks support temporary
+                                * elevation too, same ACL-TTL-reuse
+                                * mechanism and Zuse-eligibility-list gating
+                                * as the word card (§H.5). */
+    uint8_t  acl_reserved[3]; /* still genuinely undecided -- deliberate
+                                * slack per "flexibility until we understand
+                                * the recipe," not a placeholder to fill
+                                * reflexively. */
+    uint64_t reserved_future; /* untouched budget, same reasoning. */
 
     /* Link/chain support (32 bytes) */
     uint64_t prev_block; /* Previous in chain (0=none) */
@@ -238,10 +274,29 @@ typedef struct {
     /* Application-specific (120 bytes) */
     uint64_t app_data[15]; /* 15×64-bit app-defined fields */
 
-    /* Padding to reach 341-byte slice */
+    uint8_t padding[5]; /* trailing slack, unrelated to any exact size target --
-    uint8_t padding[5];
+                          * the old "341-byte slice" comment here was already
+                          * inaccurate before FABRIC-3.md §H.12 step 12's edit
+                          * (sizeof(blk_meta_t) was 344, not 341, due to
+                          * ordinary trailing struct-alignment padding after
+                          * this array -- harmless since BLK_META_PER_BLOCK,
+                          * the only thing that constant would matter to, has
+                          * zero callers anywhere in this codebase). Verify
+                          * this struct's real size with the _Static_assert
+                          * below, not by re-deriving it from this comment. */
 } blk_meta_t;
 
+/* Verified via offsetof()/sizeof(), not trusted by hand -- see the
+ * blk_volume_meta_t padding-bug lesson this project already learned once
+ * (a hand-summed struct padding formula hid a real 4-byte alignment gap).
+ * 336, not the BLK_META_PER_BLOCK/"341-byte slice" figure this struct's
+ * own comments have long claimed -- that mismatch predates this assert and
+ * is harmless today (see padding[5]'s own comment above), but this assert
+ * now makes any future drift in either direction fail the build instead of
+ * silently mismatching a constant nothing currently checks against it. */
+_Static_assert(sizeof(blk_meta_t) == 336,
+               "blk_meta_t size changed -- update this assert and check BLK_META_PER_BLOCK");
+
 /* Error codes */
 enum {
     BLK_OK = 0,
@@ -358,6 +413,24 @@ int blk_get_meta(uint32_t block_num, blk_meta_t *meta);
 
 int blk_set_meta(uint32_t block_num, const blk_meta_t *meta);
 
+/* BMAPFMT field accessors -- FABRIC-3.md §F.4/§H.6/§H.12 step 14. Thin
+ * read-modify-write wrappers over blk_get_meta()/blk_set_meta() (which
+ * already own the caching/dirty-tracking), one per new blk_meta_t field.
+ * FORTH wrappers (BLK-ACL-ALLOW@/! etc., §H.12 step 15) call these, not
+ * blk_get_meta()/blk_set_meta() directly -- same C-primitive/FORTH-policy
+ * split as the existing word-level ACL system. */
+int blk_owner_fp_get(uint32_t block_num, uint8_t out_fp[8]);
+int blk_owner_fp_set(uint32_t block_num, const uint8_t fp[8]);
+
+int blk_acl_allow_get(uint32_t block_num, uint8_t *out_allow);
+int blk_acl_allow_set(uint32_t block_num, uint8_t allow);
+
+int blk_acl_ttl_get(uint32_t block_num, uint32_t *out_ttl);
+int blk_acl_ttl_set(uint32_t block_num, uint32_t ttl);
+
+int blk_flags_get(uint32_t block_num, uint64_t *out_flags);
+int blk_flags_set(uint32_t block_num, uint64_t flags);
+
 int blk_is_allocated(uint32_t block_num);
 
 int blk_mark_allocated(uint32_t block_num);

include/starkernel/capsule_birth.h

@@ -127,6 +127,14 @@ CapsuleRunResult capsule_birth_mama(
  * @param descs         Capsule descriptor array
  * @param names         Capsule name entry array (parallel to descs)
  * @param arena         Capsule payload arena
+ * @param parent        Who is birthing this VM (FABRIC-3.md §H.12 step 7) --
+ *                       the caller's own VMUuid (e.g. vm->stadium_vm_id for
+ *                       a FORTH word handler), recorded on the new VM's
+ *                       Session.parent. Every current call site has one in
+ *                       scope, directly or one level up; traced live rather
+ *                       than assumed (checked all 6 call sites across
+ *                       mama_forth_words.c/capsule_console.c/
+ *                       capsule_runcap.c/capsule_wirebind.c).
  * @param skip_pki_sig  0 for every build-time capsule (the normal case --
  *                       checked against the compile-time-baked signature
  *                       array via capsule_get_signatures()). Non-zero only
@@ -154,6 +162,7 @@ CapsuleRunResult capsule_birth_baby(
     const CapsuleDesc *descs,
     const CapsuleNameEntry *names,
     const uint8_t *arena,
+    VMUuid parent,
     int skip_pki_sig,
     VMUuid *out_vm_id,
     void **out_vm_ctx

include/starkernel/capsule_console.h

@@ -35,11 +35,13 @@
  *                       "CaptBob"); sk_repl_dispatch_line() looks for a
  *                       live "<name>~user" counterpart to decide
  *                       whether a given active VM is a console.
+ * @param parent         Who is birthing this VM (FABRIC-3.md §H.12 step 7)
+ *                       -- passed straight through to capsule_birth_baby().
  * @param out_vm_id      Output: assigned VM ID.
  * @param out_vm_ctx     Output: new VM context (may be NULL).
  * @return CAPSULE_RUN_OK on success, error code otherwise.
  */
-CapsuleRunResult capsule_console_birth(const char *console_name,
+CapsuleRunResult capsule_console_birth(const char *console_name, VMUuid parent,
                                         VMUuid *out_vm_id, void **out_vm_ctx);
 
 #endif /* __STARKERNEL__ */

include/starkernel/capsule_runcap.h

@@ -58,6 +58,8 @@ struct blkio_dev;
  * @param vm_name     Symbolic name for the new VM (becomes both the
  *                    capsule's own single directory entry name and the
  *                    VM registry name).
+ * @param parent      Who is birthing this VM (FABRIC-3.md §H.12 step 7) --
+ *                    passed straight through to capsule_birth_baby().
  * @param out_vm_id   Output: assigned VM ID.
  * @param out_vm_ctx  Output: new VM context (may be NULL if not needed).
  * @return CAPSULE_RUN_OK on success, error code otherwise.
@@ -66,6 +68,7 @@ CapsuleRunResult capsule_runcap_birth(
     struct blkio_dev      *dev,
     const homeblocks_sig_t *sig,
     const char             *vm_name,
+    VMUuid                  parent,
     VMUuid                 *out_vm_id,
     void                  **out_vm_ctx
 );

include/starkernel/framebuffer.h

@@ -100,16 +100,22 @@ void fb_draw_orientation_test(void);
  * --------------------------------------------------------------------- */
 
 /**
- * Scroll the framebuffer up by `char_rows` character rows (each 16 px).
+ * Scroll the whole framebuffer up by `pixel_rows` pixel rows. The vacated
- * The vacated rows at the bottom are filled with bg.
+ * rows at the bottom are filled with bg. Takes an explicit pixel-row count
+ * (not a hardcoded 8x16-cell assumption) so callers with a non-8x16 cell
+ * height (e.g. TTF mode, 24px) pass their own cell height directly --
+ * same convention fb_scroll_rect() below already uses, for the same reason
+ * (a caller-computed char_rows * fixed-16px assumption drifts out of sync
+ * with the text model's own row height in TTF mode, and that drift
+ * compounds with every scroll).
  */
-void fb_scroll_rows(uint32_t char_rows, uint32_t bg);
+void fb_scroll_rows(uint32_t pixel_rows, uint32_t bg);
 
 /**
  * Scroll a sub-rectangle of the framebuffer up by `pixel_rows` pixel rows
  * (FABRIC.md item 4.4t: box-confined REPL scrolling). Unlike fb_scroll_rows()
- * (whole-framebuffer, fixed 16px-row assumption), this is bounded to
+ * (whole-framebuffer), this is bounded to
- * [x, x+w) x [y, y+h) and takes an explicit pixel-row count so callers with
+ * [x, x+w) x [y, y+h). Both take an explicit pixel-row count so callers with
  * a non-8x16 cell height (e.g. TTF mode) pass their own cell height directly.
  * Pixels outside the rect are untouched. The vacated rows at the bottom of
  * the rect are filled with bg.

include/starkernel/session.h

@@ -0,0 +1,169 @@
+/*
+  StarForth — Steady-State Virtual Machine Runtime
+
+  Copyright (c) 2023–2025 Robert A. James
+  All rights reserved.
+
+  This file is part of the StarForth project.
+
+  Licensed under the StarForth License, Version 1.0 (the "License");
+  you may not use this file except in compliance with the License.
+
+  You may obtain a copy of the License at:
+      https://github.com/star.4th@proton.me/StarForth/LICENSE.txt
+
+  This software is provided "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  express or implied, including but not limited to the warranties of
+  merchantability, fitness for a particular purpose, and noninfringement.
+
+ See the License for the specific language governing permissions and
+ limitations under the License.
+
+ */
+
+/**
+ * session.h - Per-VM session (FABRIC-3.md §H, decided 2026-09-02/03)
+ *
+ * A session is a Stadium patron (FABRIC-3.md §H.1) -- registering a session
+ * IS admitting a patron to the Stadium, not a new parallel bookkeeping
+ * structure. This struct is the piece that sits ALONGSIDE the patron,
+ * referencing it by VMUuid rather than being indexed by Stadium cell index
+ * or grown as inline fields on StadiumPatronHeader/struct VM (deliberately
+ * its own header, mirroring VMUuid's/VMIdentity's own precedent -- standing
+ * instruction: give real-shaped data its own header and integrate as a
+ * field, don't grow existing structs ad hoc).
+ *
+ * Fields (FABRIC-3.md §H.2, all five confirmed 2026-09-02/03):
+ *   vm_id    -- the patron this session references.
+ *   pinned   -- session is AUTHORITATIVE over Stadium's STADIUM_FLAG_PIN
+ *               bit (§H.10): the sole read/write path for pin state is
+ *               session_set_pinned()/session_is_pinned() below, nothing
+ *               else (including existing Stadium code) may touch
+ *               STADIUM_FLAG_PIN directly.
+ *   parent   -- who birthed this session (Hera -> Hermes/Artemis, etc).
+ *   name     -- canonical human-readable name; feeds console.c's
+ *               g_active_vm_name prefix, does not replace the
+ *               console-binding mechanism itself.
+ *   identity -- embedded VMIdentity (FABRIC-3.md §H.4's VM card is
+ *               effectively VMIdentity's existing ownership check; reused
+ *               directly here, not reinvented).
+ *
+ * Explicit user framing (2026-09-02), still true: "we're gonna be
+ * revisiting this part of it around and around for a while" -- treat this
+ * shape as a live working draft, not permanently locked.
+ */
+
+#ifndef STARKERNEL_SESSION_H
+#define STARKERNEL_SESSION_H
+
+#ifdef __STARKERNEL__
+
+#include <stdint.h>
+#include <stddef.h>
+
+#include "starkernel/vm_uuid.h"
+#include "starkernel/vm_identity.h"
+
+/* Matches console.c's CONSOLE_VM_NAME_BUF precedent -- same order of
+ * magnitude for the same kind of data (a short human-readable VM name). */
+#define SESSION_NAME_BUF 64
+
+/* Sentinel meaning "no Stadium cell recorded yet" -- same shape as
+ * STADIUM_CELL_NONE (stadium.c), duplicated here rather than pulled in via
+ * stadium.h to avoid this header depending on Stadium's internal cell-index
+ * type. Session's own callers set stadium_cell after their own
+ * stadium_admit() call returns a real index (§H.12 step 3 doc). */
+#define SESSION_STADIUM_CELL_NONE ((size_t)-1)
+
+typedef struct {
+    VMUuid     vm_id;                    /* the patron this session references */
+    int        pinned;                   /* authoritative over STADIUM_FLAG_PIN; see
+                                           * session_set_pinned()/session_is_pinned() */
+    VMUuid     parent;                   /* who birthed this session */
+    char       name[SESSION_NAME_BUF];   /* canonical human-readable name */
+    VMIdentity identity;                 /* embedded, not referenced -- see vm_identity.h */
+    size_t     stadium_cell;             /* index of this session's own patron cell in
+                                           * stadium_cells() -- SESSION_STADIUM_CELL_NONE
+                                           * until the caller that admits this session's
+                                           * patron (stadium_admit()'s return value) sets it.
+                                           * session_set_pinned()/session_is_pinned() need
+                                           * this to reach the right patron header; added
+                                           * §H.12 step 3, not part of the original H.2 field
+                                           * list -- necessary plumbing, not a new session-
+                                           * level concept, so not itself renegotiated. */
+} Session;
+
+/*
+ * session_boot_init - Boot-time allocation, mirroring stadium_boot_init()'s
+ * own kmalloc-sized-from-budget shape rather than a fixed compile-time
+ * array (stadium.c's own StadiumVMQuota table was moved off a fixed array
+ * for the same reason -- population isn't knowable in advance). Must run
+ * after stadium_boot_init() (session slot count is sized from
+ * stadium_max_vm_count()) and before the first session is registered.
+ * No callers yet (§H.12 step 2) -- wiring into the boot sequence happens
+ * in a later punch-list step.
+ *
+ * @return 0 on success, -1 if kmalloc failed or stadium_max_vm_count() is 0
+ *         (Stadium not yet initialized).
+ */
+int session_boot_init(void);
+
+/*
+ * session_find - Look up a session by the VMUuid of the patron it
+ * references. Linear scan, same shape as stadium.c's own
+ * quota_slot_for_vm() -- the population this searches is small (one entry
+ * per VM, not per word/block).
+ *
+ * @return Pointer to the live session, or NULL if none is registered for
+ *         vm_id.
+ */
+Session *session_find(VMUuid vm_id);
+
+/*
+ * session_register - Register a new session for vm_id. identity starts
+ * zeroed (VMIdentity's own documented default: installed=0, "no lock,
+ * allow freely" -- §H.12 Correction 2). pinned starts 0 (unpinned); use
+ * session_set_pinned() separately to pin, keeping this function's job to
+ * "create the session record" only, not "create and also decide pin
+ * policy" -- callers (e.g. the capsule-birth admission path, §H.12 phase 2)
+ * decide pinning themselves.
+ *
+ * @param vm_id   The patron this session references. Must not already have
+ *                a registered session (session_find(vm_id) must be NULL).
+ * @param parent  Who birthed this session (vm_uuid_hera() for Hera's own
+ *                self-registration -- self-referential, matching the
+ *                existing parent_vm_id convention documented in
+ *                capsule_run.h).
+ * @param name    Copied into the new session's name buffer, truncated to
+ *                SESSION_NAME_BUF - 1 if longer.
+ * @return Pointer to the new session, or NULL if the slot table is full,
+ *         not yet initialized, or vm_id is already registered.
+ */
+Session *session_register(VMUuid vm_id, VMUuid parent, const char *name);
+
+/*
+ * session_set_pinned / session_is_pinned - The pin-authority choke point
+ * (FABRIC-3.md §H.2/§H.10, decided 2026-09-02: "full choke point at the
+ * session level, both directions"). Session is authoritative for every
+ * EXTERNAL reader -- nothing else, including existing Stadium code, reads
+ * or writes STADIUM_FLAG_PIN on a patron header directly anymore.
+ *
+ * session_is_pinned() answers from the session's own `pinned` field
+ * directly (the authoritative copy) -- it does not re-derive the answer
+ * from Stadium. session_set_pinned() writes both: the session's own
+ * `pinned` field (authoritative) AND the mirrored STADIUM_FLAG_PIN bit on
+ * the session's own patron header (stadium_cells()[session->stadium_cell]),
+ * so the Stadium engine's own internal eviction/admission logic -- which
+ * must stay self-contained and cannot call back into session.c -- keeps
+ * seeing a correct, in-sync bit.
+ *
+ * Both no-op (return 0 / do nothing) if vm_id has no registered session, or
+ * if stadium_cell is still SESSION_STADIUM_CELL_NONE (patron not admitted
+ * yet) for the set path.
+ */
+void session_set_pinned(VMUuid vm_id, int pinned);
+int  session_is_pinned(VMUuid vm_id);
+
+#endif /* __STARKERNEL__ */
+
+#endif /* STARKERNEL_SESSION_H */

include/starkernel/vm/stadium.h

@@ -46,6 +46,16 @@
  * conflating "contains Hera" with "contains nothing." */
 #define STADIUM_CONTAINS_NONE ((uint32_t)-1)
 
+/* `flags` bit 0 -- pinned, exempt from eviction/reap. Moved here from a
+ * stadium.c-private #define (FABRIC-3.md §H.12 step 3) so session.c's pin-
+ * authority choke point (session_set_pinned()/session_is_pinned()) can
+ * write/read this same bit without a duplicate definition. Session is
+ * authoritative for every EXTERNAL reader (FABRIC-3.md §H.10) -- this bit
+ * on the raw patron header stays a mirrored copy purely for the Stadium
+ * engine's own internal eviction/admission logic (stadium.c), which must
+ * stay self-contained and not call back into session.c. */
+#define STADIUM_FLAG_PIN 0x01u
+
 /*
  * StadiumPatronHeader - one member of the closed two-valued cell union
  * (FABRIC.md §3). Nine wires: identity, heat, TTL, pin (a bit in `flags`),