# repo-mailbox

Renamed from `coord` in v0.3.0. The plugin/repo is `repo-mailbox`; the CLI
(`coord-send.sh`, `coord-inbox.sh`, `coord-done.sh`), the mailbox root
(`~/.claude/coord/`) and `CLAUDE_COORD_DIR` deliberately kept their names —
they are the transport protocol, not the product.

## Context

Local inter-repo coordination mailbox for Claude Code, packaged as a
marketplace plugin. Three components, one boundary:

- **Engine (`scripts/*.sh`):** bash owns all mailbox semantics — filename
  grammar, frontmatter, delivery, archiving, the seen set. `coord-send.sh`
  writes, `coord-inbox.sh` reads (formatted for context injection),
  `coord-done.sh` archives, `coord-count.sh` counts without delivering,
  `coord-sweep.sh` closes the aged FYI backlog machine-wide.
  Everything is pinned by `coord-selftest.sh`
  (220 checks, throwaway mailbox via `CLAUDE_COORD_DIR`).

  **`ktg-plugin-marketplace` is a RETIRED `--to` address (operator decision
  2026-08-15), rejected rather than redirected.** It is a polyrepo directory,
  not a git repo, so `basename(git toplevel)` can never resolve to it and no
  session was ever able to hold that identity naturally - mail for it belongs
  to `catalog` instead. A silent redirect was considered and declined: it
  delivers mail somewhere the sender does not believe it landed, which is the
  same misdelivery defect this closes a second time (2 messages sat
  undelivered 2 days on this exact misaddressing before `catalog`'s H4 count
  caught 6 more). Rejection fails loud at the sender, at the moment the
  mistake is made. Only `--to` is retired, not `--from` - the defect was mail
  *arriving* there, never mail claiming to *originate* there.

  **`coord-send --reply-to` asserts "marked handled" against GROUND TRUTH, and
  the exit code alone is NOT that ground truth.** The line used to print
  unconditionally with `coord-done`'s output discarded (`>/dev/null 2>&1`),
  so the one line a session relies on to close a reply debt was false at the
  moment it was printed — measured with a stub `coord-done` exiting 1: original
  still in the inbox, no `archive/`, exit 0, "marked handled". Every reply this
  repo sent had to be verified by hand afterwards, which is what a false
  success in the TRANSPORT costs. The check is `exit 0` **and** the original no
  longer being at `$COORD/$FROM/inbox/$REPLYTO`, because `coord-done` exits 0
  when it archives nothing (an unknown name is idempotently fine by its own
  contract), so a nonzero-exit test still certifies a message that never moved.
  The path is recomputed rather than reusing `$REPLY_ORIG`, which resolves to
  the inbox OR the archive — replying to an already-archived original moves
  nothing and must not warn. Failure is exit **1**, a new status: the reply WAS
  delivered and re-sending would duplicate it, so 2 stays the
  nothing-was-written status it has always been. Selftest section 34 pins all
  four cases (fails outright / exits 0 without moving / real happy path /
  archive-path reply).

  **`coord-sweep.sh` is the only path that closes a message with no human in
  the loop, and every constraint on it follows from that.** It may close exactly
  one mechanically decidable class - `reply-expected: no`, older than the grace
  window - because a message that owes a reply can only be answered by a session
  in the repo that owes it. Dry-run is the default, inverted from the rest of the
  engine, since this is the one script that destroys pending state. It closes
  through `coord-done.sh --repo` rather than moving files, so the archive layout
  and the `_broadcast` refusal stay in one place. And it logs every closure with
  sender and subject, because directed messages have no seen-tracking: the sweep
  genuinely cannot tell "seen and ignored" from "never delivered", so a notice
  can be closed unread and the log is the only record that it existed. Widening
  the class, defaulting to `--write`, or dropping the log each independently
  turn this from a bounded cleanup into silent data loss.

  **`coord-count.sh` prints TWO integers per mailbox** (`<name>\t<pending>\t<debt>`),
  and the first must stay pending: `board.sh` counts the same inbox files
  itself, so a debt-only count would put two different numbers under one name.
  Debt is read from `reply-expected` in the FRONTMATTER BLOCK ONLY - a body line
  is untrusted input and must not be able to silence a debt - and an absent
  field means a reply IS owed, because every message written before 0.11.0
  lacks it.

  **Reading is delivering — counting is not.** `coord-inbox.sh` records a
  broadcast as seen once it has printed it, so it can never be used to survey
  other repos: doing so would consume each one's backlog silently, and the seen
  set is delivery history that retraction deliberately leaves alone.
  `coord-count.sh` exists for every "what is pending" question and writes
  nothing at all. Any future read-shaped feature belongs there, not in the
  read path.
- **Hook (`hooks/scripts/session-start.mjs`):** thin zero-dependency Node
  wrapper (marketplace convention: hooks are `.mjs`) that calls
  `coord-inbox.sh` and emits the `hookSpecificOutput.additionalContext`
  envelope. No mailbox logic lives here. Always exits 0.
- **Hook (`hooks/scripts/pre-state-line-guard.mjs`):** a `PreToolUse` hook on
  `Write|Edit` that enforces the STATE.md convention's `maks ~120 linjer`
  (global CLAUDE.md; raised from `~60` by operator decision 2026-08-14 —
  see the dated paragraph below) mechanically. It exists because the prose limit alone
  failed: a real STATE.md drifted to 155-156 lines before an /insights sweep
  of 160 sessions noticed, and one trim pass on it *increased* the line count
  instead of shrinking it. org-ops dispatched the work order
  (20260814T144553Z) asking for a `PostToolUse` hook — that was the wrong
  event, and the fix is not cosmetic: `PostToolUse` fires only after the tool
  has already written the file (confirmed against the official hooks docs,
  2026-08-14 — "Can block? No", stderr is shown to the model but the write
  already landed), so it cannot stop an oversized STATE.md from landing, only
  nag about it afterward. `PreToolUse` is the only event that can deny the
  call before the file is touched, which is what "enforces" has to mean here.
  Denial is stderr + `exit 2`, matching `llm-security`'s
  `pre-write-pathguard.mjs` — the only other `PreToolUse` `Write|Edit` guard
  in this marketplace — rather than the `hookSpecificOutput.permissionDecision`
  JSON form; both block, and matching the sibling convention keeps one idiom
  for "block a write" instead of two. For `Write` the projected content is the
  call's own `content`; for `Edit` it is the CURRENT on-disk file (read fresh,
  since `PreToolUse` fires before the edit is applied) with `old_string`
  replaced by `new_string` — every occurrence when `replace_all` is set,
  otherwise only the first, mirroring what the real Edit tool does. Getting
  `replace_all` wrong in either direction is not a hypothetical: a hook that
  only ever replaced the first occurrence would silently pass a bulk edit that
  balloons the file, so `state-line-guard-selftest.sh` (21 checks) pins a
  fixture where only counting every `replace_all` occurrence produces the
  correct denial. Anything the hook cannot project with confidence — a
  missing file, an `old_string` that is not present, fields of the wrong
  type — is left to the real tool, which reports a clearer error than a guess
  here would; the guard only ever touches files named exactly `STATE.md`, at
  any depth, matching the same basename rule the global session-start hook's
  nearest-STATE-wins search already uses.

  **It is a RATCHET against the file's current size, not a flat gate at 60 —
  found by advisor review before the tag landed, not by the selftest, which
  had no fixture for it.** The first cut compared the projected line count
  only against `MAX_LINES`, never against what the file already was, so
  trimming an oversized STATE.md from, say, 156 to 100 lines — still over 60,
  but strictly smaller — was denied exactly like growing it would have been.
  Verified empirically against the real tree (2026-08-14):
  `wc -l ~/repos/*/STATE.md ~/repos/*/*/STATE.md | awk '$1 > 60'` found 23
  files already over 60 lines, one at 1405. Shipped as a flat gate, this hook
  would have made most of the machine's STATE.md files un-editable except by
  a single write landing at `<=60` in one shot — backwards for a guard whose
  whole point is making the trim the /insights finding asked for actually
  possible. The fix reads the file's current line count for BOTH tool types
  (previously only `Edit` read the file at all) and denies only when the
  projection is over `MAX_LINES` **and** larger than that current count: a
  compliant file still cannot grow past the limit, a brand-new file still
  cannot be created oversized (current defaults to 0), but an already-oversized
  file can always be edited toward compliance, one write at a time, without
  ever making it worse. Section 8 of the selftest pins all four cases:
  shrink-while-still-over-limit allows, same-size-rewrite allows, grow-an-
  already-oversized-file still denies, and create-new-oversized-file still
  denies.

  **`MAX_LINES` raised 60 -> 120, operator decision 2026-08-14 (evening),
  reported via coord by `.claude` after the global CLAUDE.md prose was
  already updated.** The ratchet mechanics above are unchanged - only the
  constant moved, plus every selftest fixture and boundary value that
  encoded 60 as a literal. Re-verified empirically against the real tree at
  the new threshold (2026-08-14): `wc -l ~/repos/*/STATE.md
  ~/repos/*/*/STATE.md | awk '$1 > 120'` found 13 files already over 120
  lines, one at 1496 - the historical 23-files-over-60/one-at-1405 figures
  above describe the tree as it was at the moment the ratchet bug was found,
  not the current threshold, and are left as-is rather than rewritten.
  `session-start.mjs`'s 160-line injection window still covers the new
  120-line limit with room to spare, so no change was needed there.

  **The Edit path's `current.replace(oldStr, newStr)` was a dollar-pattern
  injection bug, found and fixed 2026-08-15.** Passing `newStr` as a STRING
  makes JavaScript interpret `$`-sequences inside it ($&, `` $` ``, `$'`,
  `$$`, `$n`) as special replacement patterns, even though `oldStr` (the
  search side) is a plain string, not a RegExp. A `new_string` documenting
  old backtick-substitution style (`` $`cmd` ``) - exactly the prose a
  STATE.md's shell-conventions section writes routinely - triggers it.
  Measured against the real bug (`.claude/STATE.md`): a 5-line addition on a
  112-line file projected to 219 lines and was wrongly denied. Direction is
  always fail-CLOSED (never fail-open: it can only over-block, never
  under-block a real oversize), but it made exactly the kind of STATE.md
  that documents shell conventions hard to edit. Fix: replace with a
  function, `current.replace(oldStr, () => newStr)` - a function result is
  never pattern-substituted, so this covers every `$`-sequence at once, not
  a `` $` ``-specific escape. The `replace_all` branch (`split`/`join`) was
  never affected - `join` does not interpret its argument as a pattern.
  Pinned by state-line-guard-selftest.sh section 9 (`$\`` as the real repro,
  `$&` as a second sequence proving the fix is general).

  **Since ORDRE 42 (operator, 2026-08-16) it carries a SECOND invariant: the
  projected content may not claim `status=done` in its board line while the
  repo holds commits the branch's upstream does not have.** Measured that day:
  two sessions had their push refused by the UFW rate limit on port 22, said so
  honestly in the coord inbox, and wrote `status=done` regardless - board line
  green, one commit unpushed, published surface 404. `done` meant "the session
  finished" where every reader takes it to mean "the work landed", and since
  `done` drops a repo from the board plan, `morning --say <repo>` could not
  reach either of them: one defect hid the other.

  **The order recommended a session-end hook and that direction does not exist
  in the form it assumes - measured against the official hooks docs, not
  reasoned.** `Stop` fires "once per turn", not once when the session ends, with
  no signal marking the last turn; its exit 2 "prevents Claude from stopping,
  continues the conversation", so a repo that genuinely cannot push (the very
  rate limit that caused the incident) would get a session that will not end.
  `SessionEnd` is the once-per-session event and cannot block at all
  ("Can block? No" - exit 2 "shows stderr to user only"), which is the
  after-the-fact nagging the order explicitly refused. Warn-on-write plus
  deny-at-session-end inherits the broken half and buys nothing. So the deny
  sits on the write, where the false claim is actually made.

  **The false-positive trap is real but bounded, and the deny is escapable by
  telling the truth.** STATE.md is written BEFORE the session's final commit, so
  a session that batches its pushes does hold unpushed commits at that moment -
  but the global git rule already requires a push immediately after every
  commit, and the real tree bears that out (2026-08-16: 43 of 44 repos carrying
  a STATE.md had nothing unpushed; the one exception was `status=blocked` and
  honest). `status=blocked` and `status=in-progress` stay writable in the same
  single edit, so a session that cannot push is never wedged - only stopped from
  claiming otherwise.

  **No ratchet here, unlike the line limit above, and the asymmetry is the
  reason.** An oversized file needs many writes to come back under the limit, so
  denying the intermediate steps would make trimming impossible; a false `done`
  is corrected by changing one token in the write already being made. A
  "deny only the transition into done" variant was rejected outright: the
  common shape is a repo that ended `done` last session and writes `done` again
  this session, which such a rule waves straight through. It **fails OPEN** on
  every git uncertainty - no upstream, detached HEAD, missing remote-tracking
  ref, not a repo, git slow or absent - because 8 of those 44 repos have no
  upstream at all (one already `status=done`), and a confident denial resting on
  a measurement that never happened is the worse error. The board line is
  selected with `board.sh`'s own anchor (`^<!-- board:`) and the status token
  compared exactly, so prose saying `status=done` never triggers it (a STATE.md
  documenting this guard writes that string routinely) and `done2` is not `done`
  here even though board.sh's F3+F4 prefix defect still reads it as one.
  Selftest section 10, 17 checks, including the mandatory known-positive: a
  `status=done` with everything pushed must still go through, or the guard is a
  gate that denies everything and proves nothing.
- **Board (`scripts/board.sh`):** cross-repo attention board. Reads STATE.md
  next-step blocks + board lines, `git status`, and mailbox pending counts, and
  prints one line per repo. Read-only by construction: it writes to no repo, no
  STATE.md and no mailbox. Pinned by `board-selftest.sh` (217 checks).

  **It lives here because the mailbox is one of its three inputs, and it carries
  the same axis distinction the mailbox does.** A pending count means *others
  are waiting on this repo*; who a repo waits *on* comes only from its board
  line, because the message format has no reply-to field. Enforcing that in one
  of two repos would not be enforcing it. The operator invokes both `board` and
  `coord-send` exclusively through their Skill front doors, never a personal
  terminal alias — a claim this file carried until 0.12.1 (`~/.claude/scripts/board.sh`
  is a deployed copy the operator's `board()` function points at) did not survive
  inspection: no such file ever existed, and `route.sh` had no deployed copy
  either. Only the five `coord-*.sh` scripts were ever deployed there, and their
  one measured effect was an accidental fallback target for Claude sessions'
  own Bash tool calls (the bug 0.12.1 fixed) — once that fallback was gone they
  had no remaining function and were deleted.
  **`board.sh --brief` is a second RENDERING of that scan, never a second
  scan, and `brief-nightly.sh` is the only writer in that path.** The briefing
  answers the narrower question an unattended job can answer without judgement:
  which repos have an unhandled inbox, what their next step says in full, and
  the exact command to start a session in each. It prints NESTE uncut because
  the 38-character cut is the table column's property, not the record's — the
  value used to be truncated at record-build time, which left the cut string as
  the only copy. Each command is derived by CALLING `route.sh` with that repo's
  own four traits; `next-cost` alone cannot yield it, since the advisor flag is
  a property of the ROW and two rows can share a model/effort pair while
  differing on it. A repo with no route line is told so rather than handed a
  guess, because a guessed command reads as authoritative.

  **`board.sh --plan` is the THIRD rendering, and the only one that takes a
  position.** It answers which repos to open a tab for today, in what order,
  with which command. The position it takes is the ORDER and nothing else -
  there is no cutoff, so the plan hides nothing, and every term is a lookup over
  fields the scan already read. Since 0.20.0 it is FIVE ORDERED GROUPS -
  chain-root, debt, planned, in-progress, undeclared - ranked within a group by
  that group's own quantity, then a Sonnet next-cost, then oldest plan first.

  **0.19.0 shipped a weighted score here and 0.20.0 replaced it, and the
  objection the score answered is ACCEPTED, not forgotten.** A group order
  genuinely cannot express "this repo owes one message and releases two others"
  as one quantity; a score could, and that was its point. What a score could not
  do was hold still for the second consumer - re-tuning 40 against 15 silently
  reorders a parser living in another repo, and no test in THIS repo can catch
  that. The operator weighed both and chose the lookup (2026-08-03). Write that
  down every time this paragraph is edited: a later session that reads the
  objection as an unfixed defect will "restore" the score, and the round trip is
  the loop this file exists to stop.

  **`planned` ranks ABOVE `in-progress`, inverted at 0.20.0 by operator
  decision.** Turning a decision into motion is the slow step; live work is
  already moving. Flipping it back is a policy change, not a sort fix.

  **Debt is never excluded and never capped, and that is the rule most likely to
  be "fixed" into a defect.** Excluding `blocked` or `done` is a claim about a
  repo's OWN next step, which by definition cannot be moved, while owing a reply
  is the other axis entirely - answering is often what unblocks it. Measured on
  the real tree at 0.16.0, two of 26 planned repos were `done` with an unhandled
  inbox. A cap on debt was proposed with the chain credit at 0.19.0 and DECLINED
  by the operator. Sitting one group below chain-root credit is NOT that cap:
  the debtor keeps its tab, its most-owed-first position among the other
  debtors, and its `why=inbox:N`. A change that DROPPED a debtor from the plan
  would be the declined cap wearing the group order as a disguise, and selftest
  section 12 pins both halves - the root outranking four owed messages, and the
  debtor keeping everything it had.

  **"Debt" means OWED, never raw pending, since 0.22.0 - and this NARROWS what
  counts as debt, it does not reopen the paragraph above.** The paragraph above
  settles a different question: once a repo has debt, is it ever excluded or
  capped (no). This one settles what counts as debt in the first place. Through
  0.21.0, group 2's `keep`/`mag`/`why=inbox:N` and `--brief`'s whole "repo som
  skylder et svar" listing were computed from the raw pending-file count - every
  unhandled message in the inbox, including ones the sender declared
  `reply-expected: no`. That is a notice, not a request, and 0.11.0 gave
  `coord-count.sh` a second column (`owed`) for exactly this distinction - but
  `board.sh` never read it. Reported by morning-driver (2026-08-11) and
  independently reproduced against the live mailbox 2026-08-13: 27 of 72
  pending messages (37.5%) were notices. The fix joins `--plan` and `--brief`
  against `coord-count.sh`'s `owed` column by repo name (same technique as the
  chain-root `$UNBLOCKS` join below), so a `done`/`deferred`/`blocked` repo
  whose only mail is FYI no longer gets a tab, and `--brief` no longer counts a
  notice as an obligation. This reverses a decision from session 41
  (2026-08-10) that declined to build this filter, on the premise that "the
  arrival of the request IS the admission signal" - a premise that assumed
  group 2 already meant requests. It didn't; the code computed pending, the
  comments already said "owed" throughout, and the plan's own printed header
  ("Utelatt naar repoet verken skylder svar...") already claimed the exclusion
  was debt-based. The fix makes the code match what its own comments and
  header already promised. Pinned by board-selftest.sh section 8/12 fixtures
  `repo-done-fyi` (pending 2, owed 0 - excluded) and `repo-blocked-mixed`
  (pending 3, owed 2 - planned on 2, not 3). The TABLE's `INN` column and the
  raw scan (`RECORDS` field 6) are UNCHANGED - they answer "what is the state
  of every repo," not "who is waiting on you," and stay on raw pending by
  design.

  **The same 0.22.0 patch that switched `n_owe` to OWED also had to fix what
  `n_owe == 0` claims.** `--brief`'s empty-debt branch said "Ingen repo har
  uhaandtert innboks. Ingen skylder noen et svar i dag." (no repo has
  unhandled inbox; nobody owes a reply) - two claims in one branch, and only
  the second is what `n_owe == 0` actually proves once `n_owe` means OWED. A
  repo can hold FYI-only mail with zero debt, which makes the first sentence
  false while it fires - caught in review before release, not by any fixture
  (the shared test tree never reaches `n_owe == 0`, since it always carries a
  debtor). Fixed to state only the debt claim, and to name any FYI-only
  mailboxes found rather than let their existence become invisible again -
  the same "labelled, not silently dropped" principle `--plan` already
  applies to unknown-status repos. Pinned by board-selftest.sh section 14
  with its own isolated root (debt-free, one FYI-only repo).

  **The `$UNBLOCKS`/`$RECORDS` join used `NR==FNR` through 0.21.0, and that
  idiom silently drops the entire plan whenever the FIRST file is empty - fixed
  to `FILENAME==` comparison in 0.22.0, found while adding the `$OWED` join
  above.** Verified against the shipped 0.21.0 script: one in-progress repo
  with an unhandled inbox message, zero blocked repos anywhere in the tree
  (so `$UNBLOCKS` is empty, which is a common, ordinary tree state, not an
  edge case) - `--plan` printed "0 tabber". `NR==FNR` is only true for the
  FIRST file's own lines; when that file is empty, `FNR` and `NR` stay equal
  for the ENTIRE next file too (not just its first line - verified with a
  minimal awk reproduction), so every record in it is misrouted into the
  `ub[]` branch and dropped via `next`. This was invisible to
  board-selftest.sh because the fixture tree has carried at least one
  `blocked` repo since the chain-root feature shipped, and it was invisible
  on the real tree because `~/repos` currently always has one too - neither
  is a guarantee. `FILENAME==UBF`/`FILENAME==OWF` compares the exact path,
  never line counts, so an empty lookup file degrades to "nothing matched,"
  never to "everything after it is misrouted."

  **Chain-root credit lands on the ROOT and nowhere else.** For every `blocked`
  repo the `blocked-on` edge is followed transitively to the first repo that is
  not itself blocked. Crediting a blocked repo would open a tab that cannot move;
  crediting only the direct blocker leaves a two-hop chain's root uncredited,
  which is the shape the real tree actually had. A cycle, a `blocked-on` naming
  an unscanned repo, and a blocked repo with no target must all credit NOBODY:
  inventing a root there produces a plan that looks correct and sends the
  operator to the wrong repo.

  Repos with no board line rank last and are LABELLED rather than dropped,
  because the table already prints a MERK line about them and a plan that
  omitted them silently would repeat that defect.

  It renders `key=value` blocks, not prose, because it has two consumers: the
  operator, and a driver repo consuming the plan. Prose would make the rendered
  format an API no test in THIS repo could hold stable for a consumer in
  another. `command_missing=` carries both no-command causes (no route line, and
  a route line route.sh rejects) because a bare `command=` is the shape of a
  runnable command carrying nothing - a driver reading `^command=` would type an
  empty line into a live pane. `route_cmd_for()` is the single reader of the
  route-line grammar, shared with `--brief`, and distinguishes the two causes by
  exit code rather than by an empty string.

  **`paste=` and `dir=`/`command=` are the same fact for the two consumers, and
  neither is redundant.** A driver moves the pane itself and then types the
  command, so it needs them apart; a human needs ONE thing to select. Handing
  the operator two fields to join by hand is not a saved output line, it is the
  step where a session starts in the wrong repo - and it was measured the moment
  the feature met its first user, who could not act on the block at all. `paste=`
  is emitted only alongside `command=`: `paste=cd X && ` with nothing after it
  would run the cd and then a bare newline, which fails SILENTLY by leaving the
  operator in the right directory with no session started.

  **`board.sh --dispatch` is the FOURTH rendering, and the generator-ownership
  question it settles was open for two sessions.** It carries a task INTO
  another repo — "start a session in repo X, on order Y, at cost Z" — and emits
  either a plan block or a single paste line. It lives in `board.sh` rather
  than in a script of its own for one reason, and it is the reason the operator
  and `.claude` both named first: the block format has exactly ONE generator,
  and this file already is it. A second emitter of
  `tab=`/`repo=`/`dir=`/`command=`/`paste=` would be two copies of one file
  format, drifting apart, with a second place to get `paste=` wrong. Read-only
  survives untouched: every check is a read, and the two writes a dispatch needs
  (prompt file, plan file) stay with the caller — the same split
  `brief-nightly.sh` already carries for the briefing.

  **The cost comes from `route.sh`'s row table, and `--dispatch` deliberately
  refuses a `--model`/`--effort` pair.** `--advisor opus` is a property of the
  ROW; two rows share a model/effort pair while differing on it, and the CLI
  accepts a wrong advisor silently. A dispatch taking the model directly would
  have no honest source for that flag, and both available guesses produce the
  same failure — a session that looks peer-reviewed without being. A Fable
  dispatch is therefore not a `--dispatch` outcome at all, exactly as it is not
  a `route.sh` outcome; it is a hand-written override.

  **`--target-pane yes|no` is REQUIRED, with no default, and that is the same
  rule `--last-effort` carries.** It is a measurement of the world — does the
  target repo already have a Ghostty pane — and this repo must never learn to
  look for a terminal itself; the caller measures with `morning --probe-panes`
  and passes the fact in. Defaulting would be worst at `no`: that is the
  plan-file form, and `morning`'s `plan_drop_open` (morning:1788) silently drops
  a plan block for a repo that already has a pane, reporting "0 of 1" — which
  reads as a broken plan file. Measured four times on 2026-08-16 by two
  different repos. The `yes` form therefore emits **no `tab=` key at all**:
  `plan_parse` discards a block without one, so the wrong use is impossible
  rather than merely discouraged.

  **The dry-run is a parse check, not the pane gate, and the difference was
  measured (2026-08-16).** `morning --plan-file <f> --dry-run` proves the block
  parses and yields a command. Run from a Claude session there is no tty, so
  `morning` prints "window: unknown ... assuming an empty window" and
  `plan_drop_open` never fires — a gate built on it would pass the self-dispatch
  case every single time, which is the one case it would exist to catch.
  `--probe-panes`, by contrast, DOES work without a tty: it cannot identify the
  anchor pane, but the `DIR` column is there.

  **The prompt goes in argv, and only the PATH has to be shell-clean.** Verified
  directly: `"$(cat f)"` hands the file's bytes to the session as one argv
  element with no re-evaluation, so `$(...)`, backticks, quotes and UTF-8 in the
  BODY are inert — which is precisely why the prompt is passed this way instead
  of inlined. The path sits inside those quotes and IS evaluated, so it must be
  absolute (a relative one resolves against the pane's directory, not the
  emitter's) and drawn from a safe character class. An empty prompt file is
  refused with `test -s`: it would start a session and tell it nothing, which
  from the far end is indistinguishable from one waiting for a Go.

  **Driving a terminal from the plan does NOT belong here, and the measurement
  in `docs/ghostty-orchestration-measurement.md` is the argument, not taste.**
  It is a version-pinned undocumented composition over a preview API whose
  documented path is already broken upstream and whose regression was closed as
  not planned, with a blast radius reaching into other repos' live sessions.
  None of that is mailbox transport, and none of it may be able to break
  `coord-inbox` or `board`. The dependency runs one way: the driver consumes the
  plan, the plan never knows a terminal exists.

  It also cross-checks itself against `coord-count.sh`, and that is not
  belt-and-braces. The repo scan and the mailbox are two different populations:
  a mailbox can carry a name no scan will ever produce — a declared non-git
  surface (`CLAUDE_COORD_REPO`, e.g. `~/repos` itself) or a checkout outside the
  roots. Measured on the real mailbox at 0.15.0: the briefing found 11 repos /
  21 messages where `coord-count` saw 12 mailboxes / 22 pending, the missing one
  being the declared surface `repos`. A briefing that only walks the scan
  answers "who is waiting on you" with a number it quietly knows is short.

  **Zero model calls, and that is the load-bearing property, not an
  implementation detail.** The operator authenticates by subscription, so a
  headless `claude -p` job draws from the same quota pool as interactive work.
  Measured against 2.1.220: `--max-budget-usd` DOES bite under subscription auth
  (`terminal_reason: budget_exhausted`, exit 1), but it aborts AFTER turn one,
  never before it — floor ~0.25 USD-equivalent per turn on `claude-opus-5[1m]`.
  It is a runaway brake, not a pre-flight gate. Making the briefing deterministic
  removes the question entirely.

  `board.sh` stays read-only, which is why the file write lives in the wrapper
  instead of behind a `--brief --out FILE` flag. The wrapper renders to a temp
  file in the target directory and renames it into place, and treats an EMPTY
  render as a FAILED one: board prints nothing at all when its scan roots do not
  exist, which is what a mistyped path or a moved home directory looks like, and
  a plain `> file` redirect would destroy yesterday's briefing on a bad launchd
  environment. A tree where nobody owes anything is a different case — that is a
  valid, non-empty briefing saying so, and is written normally.

- **Route (`scripts/route.sh`):** pure calculator for the next session's model
  and effort. Takes four scored traits of the next task plus a required
  rationale, and prints one block of `key=value` lines: the rubric row, the rule
  that fired, the `next-cost` value, a pasteable startup command, the one-row
  cheaper fallback, and the STATE.md comment lines. Pinned by
  `route-selftest.sh` (69 checks).

  **It is here because it is the WRITER for the field `board.sh` already reads.**
  `next-cost` had a reader and no writer, so it was hand-typed every session and
  drifted into several competing spellings — cleaning the data
  could not fix that, because the cause was the missing write path. The row
  table is a closed set of six values, so a seventh cannot enter circulation,
  and section 6 of the selftest runs the round trip (route emits → board parses)
  *inside* one repo rather than across two. `board.sh` itself is untouched: a
  calculator that prints to stdout writes nothing, and the session writes
  STATE.md.

  **The row table is the operator's global rubric, moved here as the single
  copy.** It is not a second spec — `board.sh --help` documents the board line's
  *grammar* and points here for the *values*. Scoring the traits is judgement
  and belongs to the skill; turning scores into a row is a lookup and takes zero
  model calls.

  **`--advisor opus` is emitted per ROW, on a need, never unconditionally.**
  Rows 1-2 always carry it (Sonnet main model, so opus is a capability lift —
  and since every fallback is one row cheaper and the cheap rows are Sonnet,
  this is what makes the quota fallback safe to take); rows 3-4 only at
  `reversibility=costly|one-way` (Opus main model, so it buys peer review where
  a mistake is not cheap to undo); rows 5-6 never, because the CLI rejects every
  advisor for a Fable main model. The alternative — the global `advisorModel`
  setting written by `/advisor` — is what this replaces: it applies to every
  session in every repo, which is how it burned quota before. The two triggers
  are almost disjoint by construction, since `costly` forces row 3 and `one-way`
  forces row 4, so a Sonnet row always has `reversibility=cheap`.
  `verification=none` is deliberately NOT a third trigger: beyond the stakes
  rule it would only add mistakes that are cheap to reverse, docs sessions
  (`known/none/cheap/local`) among them. Section 14 pins the rule and gates the
  three CLI facts it rests on against the installed `claude` without spending a
  token — advisor validation runs before the empty-prompt check, so `-p ""`
  reaches the validator and stops there.

  **Rows 5-6 are never a `route.sh` outcome.** Until 2026-08-06 they fired
  only from an explicit `--opus-xhigh-failed` flag, mirroring a global
  CLAUDE.md policy that Fable could only be *suggested* after a failed Opus
  5/xhigh session. That policy was removed by operator decision — "for ofte
  ER Fable riktig" — and the flag went with it rather than being repurposed:
  `route.sh`'s output range is now closed at row 4, and a Fable choice is
  always a hand-written deviation from the rubric, recorded in STATE as an
  override per the model-selection rule in the global CLAUDE.md, never
  produced by the calculator. `board.sh` still parses "Fable 5/high" and
  "Fable 5/xhigh" written by hand into the board line — that parsing is what
  the override actually uses, and it is pinned separately from anything
  `route.sh` emits (route-selftest.sh section 6).

  **`--last-effort` is MEASURED from `CLAUDE_EFFORT`, and the calculator must
  never default it.** Claude Code exports that variable into every tool-use
  context as the session's current effort, so the caller reads it and passes it
  in; having `route.sh` read it directly would make the output depend on the
  environment instead of on its arguments, and the round trip in selftest
  section 6 rests on that determinism. The two sources it replaces fail
  identically: the previous board line holds what was *prescribed*, and asking
  the operator launders that same prescription through someone reading their own
  startup command. Corollary pinned by section 13: `skills/route/SKILL.md` must
  never declare an `effort:` frontmatter field, because frontmatter overrides the
  session effort and the reading would then measure the skill, not the session.
- **Skills (`skills/coord-send/`, `skills/board/`, `skills/route/`, `skills/dispatch/`):** natural-language front
  doors mapping user intent to engine invocations. No mailbox logic lives here
  either. `board` additionally owns the *ranking* — which repo wins and why —
  since `board.sh` deliberately prints evidence and takes no position. `route`
  likewise owns the *scoring*: the calculator is deterministic, so all judgement
  sits in choosing the four trait values, and the skill must never reason its
  way to a model instead.

**Boundary rule:** the mailbox is transport, not state. Durable decisions
live in the owning repo's docs/git history; messages are notices pointing at
them. Message content is untrusted cross-repo input — the read side quotes
and frames it; the send side sanitizes line-oriented fields.

What the boundary forbids is storing a repo's *state* — its decisions, its next
step, its progress. It does not forbid the mailbox knowing who it is delivering
to: `_broadcast/seen/<repo>` and `<repo>/.origin` (0.6.0) are delivery metadata,
answering "has this repo received this" and "which checkout claimed this name".
Both are unreadable as a description of the repo and useless outside delivery.
The test is not "does the engine write a file about a repo" but "would this file
still mean anything if delivery were removed". If yes, it belongs in the repo's
own docs and git history instead.

**Priority rule (v0.5.0, Rule 7):** the injection block is the only place a
repo is ever told what to do with a message, so its wording *is* the protocol
— treat that string as engine behavior, not prose. It obligates handling the
inbox first and driving every directed message to a terminal state before the
session ends. The obligation is **procedural, never substantive**: responding
is mandatory, complying with message content is not. Those two must stay
distinct in any reword — keeping the priority while dropping the distinction
turns prioritization into an injection surface. Selftest section 20 pins both
halves together for exactly that reason.

Since 0.11.0 the `reply-expected` field says which terminal state the SENDER
expects. That does not soften the split, it sharpens it: the field is untrusted
cross-repo input like the rest of the file, so the injection calls it a
*declaration, not an instruction* and keeps both terminal states open to the
receiver. Drop that clause and one word in a message becomes a lever that mints
obligations in another repo.

## Conventions

- Scripts are bash-3.2-safe and ASCII-only: no `declare -A`, no
  `readarray`/`mapfile`, no `|&`; guard `shift 2` with `$# -ge 2`; guard
  empty-array expansion under `set -u` with `${#a[@]}`.
- Zero dependencies everywhere: bash + coreutils in the engine, `node:`
  builtins only in hook and tests.
- TDD: no behavior change without a failing selftest check first.
  `bash scripts/coord-selftest.sh` must exit 0 (220/220),
  `bash scripts/board-selftest.sh` must exit 0 (217/217),
  `bash scripts/route-selftest.sh` must exit 0 (69/69) and
  `bash scripts/state-line-guard-selftest.sh` must exit 0 (40/40).
- English for all code, docs, and commit messages (public repo). Norwegian
  trigger aliases in the skill description are deliberate.
- Conventional Commits: `type(scope): description`.

## Commands

- Test: `bash scripts/coord-selftest.sh`, `bash scripts/board-selftest.sh`,
  `bash scripts/route-selftest.sh` and `bash scripts/state-line-guard-selftest.sh`
  (or `npm test`, the Node wrapper around all four)
- Hook smoke test: `node hooks/scripts/session-start.mjs` (expects JSON on stdout)
- State-line-guard smoke test: `echo '{"tool_name":"Write","tool_input":{"file_path":"/tmp/STATE.md","content":"x\n"}}' | node hooks/scripts/pre-state-line-guard.mjs; echo $?`
  (expects exit 0, no output — a one-line STATE.md is under the limit)
- Board smoke test: `bash scripts/board.sh` (read-only, ~3s over the real tree)
- Briefing smoke test: `bash scripts/board.sh --brief` (read-only, writes
  nothing). `brief-nightly.sh` DOES write — it overwrites `$CLAUDE_BRIEF_FILE`
  (default `~/.claude/briefing.md`), so point that at a scratch path when
  testing. Installed as a launchd agent from `launchd/`, which points at the
  SOURCE repo, never the version-pinned plugin cache.
- Dispatch smoke test: `bash scripts/board.sh --dispatch --repo repo-mailbox
  --prompt-file /tmp/x.prompt --target-pane yes --path known --verification
  strong --reversibility cheap --scope local --rationale smoke` (read-only;
  needs a non-empty `/tmp/x.prompt`. Use `--target-pane yes` in a smoke test:
  it produces no plan file, so nothing can be handed to `morning` by accident)
- Route smoke test: `bash scripts/route.sh --path known --verification strong
  --reversibility cheap --scope local --rationale x` (writes nothing, instant)
- Sweep smoke test: `bash scripts/coord-sweep.sh` (dry-run is the default, so
  this writes nothing; never add `--write` to a smoke test against the real
  mailbox)

## Release

Version must agree across: `.claude-plugin/plugin.json`, `package.json`,
README version badge, `skills/coord-send/SKILL.md`, `skills/board/SKILL.md`,
`skills/route/SKILL.md` and `skills/dispatch/SKILL.md` frontmatter, git tag `vX.Y.Z`, and the catalog `ref` in
`ktg-plugin-marketplace/catalog/.claude-plugin/marketplace.json`. Release via
the catalog's `scripts/release-plugin.mjs repo-mailbox` (tag + ref bump
together);
verify with `scripts/check-versions.mjs`. Never hand-edit a ref.

Two things that script does that its dry-run label does not suggest:
`--create-tag` creates AND pushes the tag even without `--write`, and its
closing verification gate runs `check-versions.mjs` over ALL plugins — one
unrelated plugin in ERROR aborts it with the catalog edit written but
uncommitted. When that happens, commit the catalog's `marketplace.json` +
`README.md` by hand and leave every other dirty file in that repo alone.

**`--write --commit` does NOT close this window (confirmed by catalog,
2026-08-10).** The gate (`check-versions.mjs`) runs via `execFileSync` before
the `--commit` conditional, so it throws on any plugin's ERROR — including one
we did not touch — after the catalog files are written and before commit,
regardless of whether `--commit` was passed. Catalog is evaluating a
pre-flight gate (run the check before writing, abort there) but it is **not
implemented yet** — do not assume it exists. Until it ships: before running
`--write`, run `node scripts/check-versions.mjs` in the catalog manually and
confirm 0 ERROR first, even when the only ERROR belongs to an unrelated
plugin. If it still fires mid-release, fall back to the manual-commit
recovery above.

## Hardening roadmap

Empty — the post-v0.1.0 queue (atomic delivery, `.`/`..` rejection,
selftest gaps, uniform `-h`) shipped in v0.2.0; broadcast self-delivery
shipped in v0.2.1; broadcast retraction (`coord-send --retract`) shipped in
v0.4.0, closing the last monotonically-growing surface. `coord-inbox.sh`
still ignores unknown arguments by design (hook context must never fail)
but now warns about each one on stderr, which the hook discards.

Two retraction limits are deliberate, not gaps: it is un-send and never
recall (a repo that already received a broadcast keeps it — the seen set is
delivery history and is left untouched), and the sender check is an accident
guard, not a security boundary, because `--from` redefines identity here as
it does everywhere else in the engine.