fix(skill): stale user-level skill copy shadowed injections; seed the preamble

Two live failures from one root cause: Claude Code loads a same-named
user-level skill (~/.claude/skills/codeman, written once by `codeman skill
install`) over the fresh per-case copy, and nothing ever refreshed it. A
stale Aug-9 copy (pre fast-path, pre lineage header) made every agent-driven
spawn run the old recipes: workers spawned serially with pid polls and
without X-Codeman-Parent-Session, so the web UI drew no lineage arcs.

- refreshUserAgentSkill(): session create now refreshes a marker-owned
  user-level copy (refresh-only: absent copies are not installed,
  foreign/symlink copies stay untouched).
- seedAgentSessionPreamble(): local claude session create pre-seeds the
  skill's preamble into ${XDG_CACHE_HOME:-~/.cache}/codeman-agent-<id>.sh,
  single-sourced from the new skills/codeman/preamble.sh, so the skill's §0
  bootstrap collapses to a two-line loader instead of a ~150-line paste the
  model has to type out (measured ~47s of generation per run).
- SKILL.md: §0 now leads with the loader and keeps the full block as the
  stale/missing fallback; explicit verbatim-paste warning (a hand-assembled
  preamble is how the header and the fast-path functions got lost);
  spawn_worker also sends parentSessionId in the body as defense in depth;
  preamble stamp bumped to 1.18.3 so pre-fix cached preambles self-heal.
- test/agent-skill.test.ts pins preamble.sh byte-identical to the SKILL.md
  heredoc and covers seeding (XDG + HOME fallback, 0600) and the user-level
  refresh (absent/stale/foreign).

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

CLAUDE.md

@@ -182,7 +182,7 @@ Codeman is a Claude Code session manager with web interface and autonomous Ralph
 
 **Input**: `session.writeViaMux()` for programmatic/curl input via tmux `send-keys -l` + `send-keys Enter`, single-line only. Interactive **browser** input goes through a durable **exactly-once** layer: a stable `clientId` + monotonic per-session `seq` persisted to localStorage until the server ACKs, so a dropped link cannot lose or double-deliver a prompt. `ws-connection-registry.ts` supersedes only same-TAB reconnects, so two tabs on one session coexist. → [architecture-invariants#input-delivery-and-ws-resilience](docs/architecture-invariants.md#input-delivery-and-ws-resilience)
 
-**Agent wait primitives**: bounded long-polls so an agent driving Codeman from a shell can block instead of poll: `GET /api/sessions/:id/wait` (lifecycle signal), `GET /api/sessions/:id/wait-output` (literal substring, **never** regex) and `wait`/`waitTimeout` on `POST /api/sessions/:id/input`. Registry in `session-wait-registry.ts` (pure, no `Session` reference), bounds in `config/agent-wait.ts`. ⚠️ **A timeout is a 200** (`wait.timedOut`), never an error, so callers loop over short waits. ⚠️ `stop`/`blocked` come from Claude Code hooks and therefore fire for **`claude` mode ONLY** (`shell` installs none either); asking for one explicitly on another mode is a 400, the default set silently drops them. ⚠️ Send-and-wait registers the waiter BEFORE the write (a separate POST-then-wait races and reports the PREVIOUS turn), and both teardown paths must `notifySignal('exit')` BEFORE `cancelAll()`. ⚠️ Client-hangup abort listens on **`reply.raw`** guarded by `writableFinished`: on `req.raw`, `close` fires when the request BODY ends, which on a POST killed every send-and-wait instantly and no `app.inject()` test could see it. ⚠️ Worker liveness cannot come from `session.pid` — for a tmux session that is the local attach client, which outlives a worker dying inside its pane — so it is probed at the mux layer (`isPaneDead`, ~750 ms cache) on blocking waits only, never on the input hot path. ⚠️ Signals are edge-triggered with no history: one that fires with no waiter registered is unobservable afterwards, so gather fan-outs with send-and-wait or latched `wait-output` markers, never fire-and-forget-then-sequential-signal-waits. The primitives are packaged as the **`skills/codeman` agent skill**: installable via `codeman skill install [--case <name>]` / `skill uninstall`, or auto-injected into a case's `.claude/skills/` on Claude session create behind `agentSkillEnabled` (SYNCED, default OFF). Injection is ADD-ONLY at create, marker-owned (`applyAgentSkill` in `hooks-config.ts` never touches an unmarked user copy) and refuses symlinks (this repo's own `.claude/skills/codeman` is a symlink to the source, which the injector must never write through). → [architecture-invariants#agent-wait-primitives](docs/architecture-invariants.md#agent-wait-primitives), `docs/api-reference.md`
+**Agent wait primitives**: bounded long-polls so an agent driving Codeman from a shell can block instead of poll: `GET /api/sessions/:id/wait` (lifecycle signal), `GET /api/sessions/:id/wait-output` (literal substring, **never** regex) and `wait`/`waitTimeout` on `POST /api/sessions/:id/input`. Registry in `session-wait-registry.ts` (pure, no `Session` reference), bounds in `config/agent-wait.ts`. ⚠️ **A timeout is a 200** (`wait.timedOut`), never an error, so callers loop over short waits. ⚠️ `stop`/`blocked` come from Claude Code hooks and therefore fire for **`claude` mode ONLY** (`shell` installs none either); asking for one explicitly on another mode is a 400, the default set silently drops them. ⚠️ Send-and-wait registers the waiter BEFORE the write (a separate POST-then-wait races and reports the PREVIOUS turn), and both teardown paths must `notifySignal('exit')` BEFORE `cancelAll()`. ⚠️ Client-hangup abort listens on **`reply.raw`** guarded by `writableFinished`: on `req.raw`, `close` fires when the request BODY ends, which on a POST killed every send-and-wait instantly and no `app.inject()` test could see it. ⚠️ Worker liveness cannot come from `session.pid` — for a tmux session that is the local attach client, which outlives a worker dying inside its pane — so it is probed at the mux layer (`isPaneDead`, ~750 ms cache) on blocking waits only, never on the input hot path. ⚠️ Signals are edge-triggered with no history: one that fires with no waiter registered is unobservable afterwards, so gather fan-outs with send-and-wait or latched `wait-output` markers, never fire-and-forget-then-sequential-signal-waits. The primitives are packaged as the **`skills/codeman` agent skill**: installable via `codeman skill install [--case <name>]` / `skill uninstall`, or auto-injected into a case's `.claude/skills/` on Claude session create behind `agentSkillEnabled` (SYNCED, default OFF). Injection is ADD-ONLY at create, marker-owned (`applyAgentSkill` in `hooks-config.ts` never touches an unmarked user copy) and refuses symlinks (this repo's own `.claude/skills/codeman` is a symlink to the source, which the injector must never write through). ⚠️ Claude Code loads a same-named USER-LEVEL skill (`~/.claude/skills/codeman`, written once by `codeman skill install` with no `--case`) over the per-case copy, and nothing used to refresh it: a stale Aug-9 user copy shadowed every fresh injection (2026-08-14: agents ran the old recipes, spawned workers serially and lost their lineage arcs), so session create now also refreshes a marker-owned user copy (`refreshUserAgentSkill`; refresh-only, never installs, foreign/symlink refused). Session create additionally pre-seeds the skill's §0 preamble cache (`seedAgentSessionPreamble` → `${XDG_CACHE_HOME:-~/.cache}/codeman-agent-<id>.sh`, local claude sessions only), single-sourced from `skills/codeman/preamble.sh` and pinned byte-identical to SKILL.md's §0 heredoc by `test/agent-skill.test.ts`, so the skill's bootstrap is a two-line loader instead of a ~150-line paste the model types out (~47 s of generation, measured live). → [architecture-invariants#agent-wait-primitives](docs/architecture-invariants.md#agent-wait-primitives), `docs/api-reference.md`
 
 **Idle detection**: Multi-layer (completion message → AI check → output silence → token stability). See `docs/respawn-state-machine.md`.
 

skills/codeman/SKILL.md

@@ -41,7 +41,28 @@ the preamble to a file once and source it afterwards, rather than re-pasting a
 hundred-odd lines at the top of every call (a half-re-pasted preamble used to be the
 single most likely way to break a run).
 
-Run this block once per Codeman session:
+**Codeman seeds the preamble file for you** when it spawns a claude session (server
+1.18.3+), so the bootstrap is usually just loading it — the same two lines every later
+call starts with:
+
+```bash
+. "${XDG_CACHE_HOME:-$HOME/.cache}/codeman-agent-$CODEMAN_SESSION_ID.sh" 2>/dev/null
+[ "${CODEMAN_PREAMBLE:-}" = 1.18.3 ] || { echo "preamble missing or stale; run the full §0 block"; exit 1; }
+```
+
+If that passed, §0 is done: go straight to your job (§1's block opens with this same
+loader, so when §1 is the job you can simply start there). Only when it reports
+missing or stale, run the full block below once — and run it **verbatim**: paste it
+as-is, never re-type it, trim it, or "extract the parts you need". A hand-assembled
+preamble is the documented failure mode of this skill: one live run rebuilt it
+"minimally" and lost the `X-Codeman-Parent-Session` header (every worker spawned with
+no lineage arc in the web UI) and the fast-path functions (the spawn fell back to a
+serial quick-start loop plus pid polls), turning a ten-second job into a fifty-second
+one. If your harness directs temporary files into a scratchpad directory, that
+directive covers task scratch, not this file: it is a per-session cache that every
+later call re-sources by this exact path, so keep the path below. If you must relocate
+it anyway, copy the block's content byte-for-byte unchanged and source your path in
+every later call instead.
 
 ```bash
 test "${CODEMAN_MUX:-}" = 1 || { echo "Not inside a Codeman-managed session; refusing to act."; exit 1; }
@@ -50,8 +71,8 @@ PRE="${XDG_CACHE_HOME:-$HOME/.cache}/codeman-agent-$CODEMAN_SESSION_ID.sh"
 mkdir -p "$(dirname "$PRE")"
 # Rewrite unless the file already ends with THIS version's stamp, so a stale or a
 # half-written file self-heals here instead of costing you a round trip to rm it.
-grep -qs '^CODEMAN_PREAMBLE=1.18.2$' "$PRE" || (umask 077; cat > "$PRE" <<'PREAMBLE'
+grep -qs '^CODEMAN_PREAMBLE=1.18.3$' "$PRE" || (umask 077; cat > "$PRE" <<'PREAMBLE'
-# ---- Codeman agent preamble 1.18.2 (written by the SKILL.md §0 bootstrap) ----
+# ---- Codeman agent preamble 1.18.3 (seeded by Codeman at session spawn; the SKILL.md §0 bootstrap rewrites it when missing or stale) ----
 API="${CODEMAN_API_URL:?CODEMAN_API_URL not set; refusing to guess}"
 SELF="${CODEMAN_SESSION_ID:?CODEMAN_SESSION_ID not set}"
 # Credentials, cheapest first. Your session has usually INHERITED the server's
@@ -105,8 +126,10 @@ _composer_up() {   # <sid> <timeoutMs> -> "true"/"false". `shift+tab` is the one
 # composer draws, and pid!=null proved startup, never readiness.
 spawn_worker() {
   local name="${1:?spawn_worker needs a case name}" mode="${2:-claude}" q sid cp r
+  # parentSessionId doubles the CURL header, so a spawn_worker copied off the shared
+  # curl (or a body someone rebuilt from this recipe) still carries its lineage.
   q=$("${CURL[@]}" -X POST "$API/api/v1/quick-start" -H 'Content-Type: application/json' \
-      -d "$(jq -nc --arg n "$name" --arg m "$mode" '{caseName:$n,mode:$m}')")
+      -d "$(jq -nc --arg n "$name" --arg m "$mode" --arg p "$SELF" '{caseName:$n,mode:$m,parentSessionId:$p}')")
   sid=$(jq -r 'if .success then .data.sessionId else empty end' <<<"$q")
   # NOT retryable in a loop: every quick-start failure code is terminal (§5.1).
   [ -n "$sid" ] || { jq -c '{error,errorCode}' <<<"$q" >&2; return 1; }
@@ -206,18 +229,14 @@ last_text() {
 # The stamp is the LAST line on purpose (a truncated write leaves it unset) and is kept
 # bare on purpose: the write condition above anchors on it with $, so an inline comment
 # here would fail that match and rewrite this file on every single bootstrap.
-CODEMAN_PREAMBLE=1.18.2
+CODEMAN_PREAMBLE=1.18.3
 PREAMBLE
 )
-. "$PRE"; [ "${CODEMAN_PREAMBLE:-}" = 1.18.2 ] || { echo "preamble at $PRE is stale or truncated: rm it and re-run this block"; exit 1; }
+. "$PRE"; [ "${CODEMAN_PREAMBLE:-}" = 1.18.3 ] || { echo "preamble at $PRE is stale or truncated: rm it and re-run this block"; exit 1; }
 ```
 
-Every later Bash call that touches the API starts with these two lines instead:
+Every later Bash call that touches the API starts with the same two loader lines from
-
+the top of this section.
-```bash
-. "${XDG_CACHE_HOME:-$HOME/.cache}/codeman-agent-$CODEMAN_SESSION_ID.sh" 2>/dev/null
-[ "${CODEMAN_PREAMBLE:-}" = 1.18.2 ] || { echo "preamble missing or stale; re-run the §0 bootstrap"; exit 1; }
-```
 
 Why it is built this way, all of it load-bearing:
 
@@ -259,7 +278,8 @@ Fill in the case names and the prompts. Everything below is `spawn_workers` /
 to assemble and no per-call body to hand-build.
 
 ```bash
-. "${XDG_CACHE_HOME:-$HOME/.cache}/codeman-agent-$CODEMAN_SESSION_ID.sh"   # §0
+. "${XDG_CACHE_HOME:-$HOME/.cache}/codeman-agent-$CODEMAN_SESSION_ID.sh" 2>/dev/null   # §0 loader
+[ "${CODEMAN_PREAMBLE:-}" = 1.18.3 ] || { echo "preamble missing or stale; run the full §0 block"; exit 1; }
 N=(alpha beta)                                        # one FRESH case name per worker
 T=('reply with one line: the absolute path of your working directory'
    'reply with one line: your model name')            # tasks, same order as N
@@ -292,7 +312,11 @@ the time went into deliberation, not the API. The three things that actually cos
 - **Spawning serially.** One worker per Bash call is one model turn per worker. `&` plus
   `wait`, as above, makes N workers cost about what one costs.
 - **Re-deriving the happy path** from §5.1 + §5.2 + §5.3 + §5.10. That is what the
-  preamble functions exist to end. Compose them; do not rebuild them.
+  preamble functions exist to end. Compose them; do not rebuild them. The tells that
+  you are rebuilding anyway: a `for` loop around `quick-start`, a poll on `.data.pid`,
+  a bespoke `ready()` or `spawn()` of your own. Each is a worse copy of a function
+  already sitting in your preamble; the live run that wrote them spawned serially,
+  polled pid for nothing, and shipped its workers without lineage.
 - **Verifying what is already checked for you.** Two verifications specifically are not
   worth a call here, because `spawn_worker` carries them: the hooks check (it refuses a
   name that resolved to a hook-less directory with one local grep, so a worker it hands

skills/codeman/preamble.sh

@@ -0,0 +1,158 @@
+# ---- Codeman agent preamble 1.18.3 (seeded by Codeman at session spawn; the SKILL.md §0 bootstrap rewrites it when missing or stale) ----
+API="${CODEMAN_API_URL:?CODEMAN_API_URL not set; refusing to guess}"
+SELF="${CODEMAN_SESSION_ID:?CODEMAN_SESSION_ID not set}"
+# Credentials, cheapest first. Your session has usually INHERITED the server's
+# CODEMAN_PASSWORD already (§6 explains why, and what to do when it has not);
+# the data dir's .env is the documented fallback, the same one `codeman attach`
+# reads. The data dir is wherever the hook-secret file lives. Values may be
+# quoted or `export`-prefixed.
+ENV_FILE="${CODEMAN_HOOK_SECRET_FILE:+${CODEMAN_HOOK_SECRET_FILE%hook-secret}.env}"
+envval() { sed -n "s/^\(export \)\{0,1\}$1=//p" "$ENV_FILE" | tail -1 | sed 's/^"\(.*\)"$/\1/; s/^'\''\(.*\)'\''$/\1/'; }
+if [ -z "${CODEMAN_PASSWORD:-}" ] && [ -n "$ENV_FILE" ] && [ -f "$ENV_FILE" ]; then
+  CODEMAN_USERNAME=$(envval CODEMAN_USERNAME)
+  CODEMAN_PASSWORD=$(envval CODEMAN_PASSWORD)
+fi
+AUTH=(); [ -n "${CODEMAN_PASSWORD:-}" ] && AUTH=(-u "${CODEMAN_USERNAME:-admin}:$CODEMAN_PASSWORD")
+# -k: harmless on http, required on https (self-signed cert).
+# X-Codeman-Parent-Session: tags workers YOU spawn as your children, so the web UI can
+# draw the lineage. Set once here and every present and future create call carries it;
+# it is ignored on every other endpoint. Purely cosmetic (see §5.1) and it can never
+# fail a spawn, so there is no case where you would want to leave it off.
+CURL=(curl -sk "${AUTH[@]}" -H "X-Codeman-Parent-Session: $SELF")
+CID=codeman-agent-1            # FIXED literal, never "agent-$$": see below
+
+# Fail-CLOSED session delete. The DELETE lives INSIDE the guard on purpose: the older
+# `is_self "$SID" || curl -X DELETE ...` shape failed OPEN, because an undefined
+# is_self exits 127 and the `||` branch then ran the delete completely unguarded.
+# Undefined delete_session is "command not found", which deletes nothing.
+delete_session() {
+  local id="${1:-}"
+  [ -n "$id" ] || { echo "refusing: empty session id"; return 1; }
+  [ "${#SELF}" -ge 8 ] || { echo "refusing: \$SELF unset or too short to prove this is not me"; return 1; }
+  # ids appear in full AND 8-char form (Docker exports a truncated $SELF; mux names and
+  # UI surfaces carry 8-char ids), so compare by prefix in BOTH directions. Equality or
+  # a one-directional check each miss a real combination, and the miss deletes you.
+  case "$id" in "$SELF"*) echo "refusing: $id is me"; return 1 ;; esac
+  case "$SELF" in "$id"*) echo "refusing: $id is me"; return 1 ;; esac
+  "${CURL[@]}" -X DELETE "$API/api/v1/sessions/$id"
+}
+
+# ---- fast path: the four verbs, already written. §1 composes them. ----
+_composer_up() {   # <sid> <timeoutMs> -> "true"/"false". `shift+tab` is the one token
+  "${CURL[@]}" -G "$API/api/v1/sessions/$1/wait-output" \
+    --data-urlencode 'match=shift+tab' --data-urlencode 'from=buffer' \
+    --data-urlencode "timeout=$2" | jq -r '.data.wait.matched // false'
+}
+# spawn_worker <caseName> [mode] -> session id on stdout, diagnostics on stderr.
+# quick-start AND readiness in one call, with a strict contract: NON-EMPTY stdout means
+# a READY claude worker in a hook-carrying case. Anything less is rc 1 with EMPTY
+# stdout, and the half-spawned session is deleted here rather than handed back, because
+# a worker that never drew its composer would eat the task prompt with its trust
+# dialog. There is deliberately no pid poll: wait-output already blocks until the
+# composer draws, and pid!=null proved startup, never readiness.
+spawn_worker() {
+  local name="${1:?spawn_worker needs a case name}" mode="${2:-claude}" q sid cp r
+  # parentSessionId doubles the CURL header, so a spawn_worker copied off the shared
+  # curl (or a body someone rebuilt from this recipe) still carries its lineage.
+  q=$("${CURL[@]}" -X POST "$API/api/v1/quick-start" -H 'Content-Type: application/json' \
+      -d "$(jq -nc --arg n "$name" --arg m "$mode" --arg p "$SELF" '{caseName:$n,mode:$m,parentSessionId:$p}')")
+  sid=$(jq -r 'if .success then .data.sessionId else empty end' <<<"$q")
+  # NOT retryable in a loop: every quick-start failure code is terminal (§5.1).
+  [ -n "$sid" ] || { jq -c '{error,errorCode}' <<<"$q" >&2; return 1; }
+  [ "$mode" = claude ] || { printf '%s\n' "$sid"; return 0; }   # only claude draws a composer
+  # quick-start RESOLVES the name before creating: a linked case or an existing dir
+  # wins over a fresh scratch case, so "created => hooks" is only true after this one
+  # local grep (the same marker the server itself checks for). No marker means sendwait
+  # would false-resolve on flapping idle, possibly inside the user's REAL repo: refuse
+  # rather than run the job there.
+  cp=$(jq -r '.data.casePath // empty' <<<"$q")
+  grep -qs '/api/hook-event' "$cp/.claude/settings.local.json" || {
+    echo "case '$name' resolved to '$cp', which has no Codeman hooks (linked or pre-existing?): pick an unused name, or work §5.1+§5.5 by hand" >&2
+    delete_session "$sid" >/dev/null; return 1; }
+  # Short composer wait FIRST, then the trust-dialog probe: a case still showing the
+  # dialog can never pass the composer wait, so probing early keeps a cold case from
+  # paying the whole long wait before the fallback even runs (§5.2). A warm case
+  # matches in under a second and never reaches the probe.
+  r=$(_composer_up "$sid" 5000)
+  if [ "$r" != true ]; then
+    if "${CURL[@]}" -G "$API/api/v1/sessions/$sid/wait-output" \
+         --data-urlencode 'match=trust' --data-urlencode 'from=buffer' --data-urlencode 'timeout=2000' \
+       | jq -e '.data.wait.matched' >/dev/null; then
+      # Codeman's own auto-accept gives up after 90 s / 3 tries; this is that bounded fallback.
+      "${CURL[@]}" -X POST "$API/api/v1/sessions/$sid/input" -H 'Content-Type: application/json' \
+        -d "$(jq -nc --arg c "$CID-$sid" '{input:"\r",useMux:true,clientId:$c,seq:1}')" >/dev/null
+    fi
+    r=$(_composer_up "$sid" 45000)
+  fi
+  [ "$r" = true ] || { echo "worker $sid never drew a composer; deleted it. Retry by hand via the §5.2 ladder (its billed stage-4 probe included)" >&2
+    delete_session "$sid" >/dev/null; return 1; }
+  printf '%s\n' "$sid"
+}
+# spawn_workers <caseName>... -> one "<caseName> <sessionId>" line per worker, in order;
+# the sessionId column is EMPTY for a spawn that failed (stderr has why). CONCURRENT:
+# N workers cost about what one costs. Spawning them one Bash call at a time is the
+# single biggest avoidable delay in this skill. Names must be UNIQUE: two workers in
+# one case directory co-edit the same tree (§4), so a repeat is an error here, not a race.
+spawn_workers() {
+  local d n i=0
+  [ "$#" -gt 0 ] || { echo "spawn_workers: no case names given" >&2; return 1; }
+  [ -z "$(printf '%s\n' "$@" | sort | uniq -d)" ] || { echo "spawn_workers: duplicate case names" >&2; return 1; }
+  d=$(mktemp -d "${TMPDIR:-/tmp}/codeman-spawn.XXXXXX") || return 1
+  for n in "$@"; do ( spawn_worker "$n" > "$d/$i" ) & i=$((i+1)); done
+  wait
+  i=0; for n in "$@"; do printf '%s %s\n' "$n" "$(cat "$d/$i" 2>/dev/null)"; i=$((i+1)); done
+  rm -rf "$d"
+}
+# sendwait <sid> <prompt> [seq] -> blocks until that worker's turn ENDS (~10 min ceiling
+# across its two waits). One billed turn. The \r and the per-worker clientId are applied
+# here, which is why you never hand-build this body. seq defaults to the CURRENT EPOCH
+# SECOND so that every new prompt is a new frame: the server drops any (clientId,seq)
+# pair it has already applied, so a fixed default would make every later prompt to that
+# worker a silent no-op that still "succeeds" and reports the previous turn's state.
+# Pass seq explicitly for exactly one reason: resending a possibly-delivered frame as a
+# deliberate duplicate, at the SAME number (§5.3).
+# Delivery is SELF-HEALING: an Ink repaint occasionally eats the Enter, leaving the
+# typed prompt stranded on the composer while a long wait runs its whole timeout
+# (observed live). So the first wait is short; on its timeout a bare \r goes out (the
+# missing Enter when the prompt is stranded, a no-op when the turn is genuinely
+# running), then the ORIGINAL frame is resent unchanged, which the server takes as a
+# tagged duplicate: it re-waits without retyping (§5.3). Trustworthy only for a claude
+# worker spawn_worker handed back (hooks vetted); hook-less workspaces and other modes
+# resolve on flapping idle: markers instead (§5.5).
+sendwait() {
+  local sid="${1:?}" p="${2:?}" seq="${3:-$(date +%s)}" body r
+  body=$(jq -nc --arg p "$p" --arg c "$CID-$sid" --argjson s "$seq" \
+    '{input:($p+"\r"),useMux:true,clientId:$c,seq:$s,wait:true,waitTimeout:20000}')
+  r=$("${CURL[@]}" -X POST "$API/api/v1/sessions/$sid/input" \
+        -H 'Content-Type: application/json' --data-binary "$body")
+  if jq -e '.data.delivered and .data.wait.timedOut' <<<"$r" >/dev/null 2>&1; then
+    "${CURL[@]}" -X POST "$API/api/v1/sessions/$sid/input" -H 'Content-Type: application/json' \
+      -d "$(jq -nc --arg c "$CID-$sid" --argjson s "$(date +%s)" \
+        '{input:"\r",useMux:true,clientId:$c,seq:$s}')" >/dev/null
+    r=$("${CURL[@]}" -X POST "$API/api/v1/sessions/$sid/input" \
+          -H 'Content-Type: application/json' --data-binary "$(jq -c '.waitTimeout=580000' <<<"$body")")
+  fi
+  printf '%s\n' "$r"
+}
+# last_text <sid> [prev] -> that worker's last assistant message. Polled, because the
+# transcript write LAGS the stop signal, and "some text exists" is not "THIS turn's
+# text exists": right after a SECOND turn on the same worker the endpoint still serves
+# the previous answer for a beat (observed live). When reading consecutive turns, pass
+# the previous answer as [prev]: the poll then holds out for text that differs from it,
+# falling back to whatever it last saw if the budget runs dry, so an honestly repeated
+# answer still comes back. Non-zero exit means the worker really never wrote one.
+last_text() {
+  local t="" prev="${2:-}"
+  for _ in $(seq 1 15); do
+    t=$("${CURL[@]}" "$API/api/v1/sessions/$1/last-response" | jq -r '.data.text // empty')
+    [ -n "$t" ] && [ "$t" != "$prev" ] && { printf '%s\n' "$t"; return 0; }
+    sleep 1
+  done
+  [ -n "$t" ] && { printf '%s\n' "$t"; return 0; }
+  return 1
+}
+
+# The stamp is the LAST line on purpose (a truncated write leaves it unset) and is kept
+# bare on purpose: the write condition above anchors on it with $, so an inline comment
+# here would fail that match and rewrite this file on every single bootstrap.
+CODEMAN_PREAMBLE=1.18.3

skills/codeman/reference/recipes.md

@@ -21,7 +21,7 @@ by sourcing the preamble file the §0 bootstrap wrote, and checking its version
 
 ```bash
 . "${XDG_CACHE_HOME:-$HOME/.cache}/codeman-agent-$CODEMAN_SESSION_ID.sh" 2>/dev/null
-[ "${CODEMAN_PREAMBLE:-}" = 1.18.2 ] || { echo "preamble missing or stale; re-run the §0 bootstrap"; exit 1; }
+[ "${CODEMAN_PREAMBLE:-}" = 1.18.3 ] || { echo "preamble missing or stale; re-run the §0 bootstrap"; exit 1; }
 ```
 
 Do **not** re-paste the preamble body into each call. Sourcing it is what retires the

src/hooks-config.ts

@@ -31,6 +31,7 @@
 import { randomBytes } from 'node:crypto';
 import { existsSync } from 'node:fs';
 import { readFile, writeFile, mkdir, lstat, readdir, realpath, rename, unlink, rmdir } from 'node:fs/promises';
+import { homedir } from 'node:os';
 import { join, dirname } from 'node:path';
 import { fileURLToPath } from 'node:url';
 
@@ -948,6 +949,49 @@ export async function installAgentSkillInto(skillDir: string): Promise<AgentSkil
   });
 }
 
+/**
+ * Seed a claude session's agent preamble file (`$XDG_CACHE_HOME/codeman-agent-<id>.sh`,
+ * default `~/.cache/`) from the packaged `skills/codeman/preamble.sh`, so the agent
+ * skill's §0 bootstrap collapses to a two-line loader instead of a ~150-line block the
+ * model has to type out (measured live: that paste alone cost a spawn run ~47 s of
+ * generation time). The path formula must match the skill's
+ * `${XDG_CACHE_HOME:-$HOME/.cache}` exactly; sessions inherit the server's env, so
+ * reading the server's own XDG_CACHE_HOME keeps the two in agreement (`||` mirrors the
+ * shell's `:-`, treating empty as unset). Callers gate to LOCAL claude sessions (a
+ * remote or in-container HOME is not this filesystem) and treat it as best-effort: the
+ * skill's §0 fallback block self-heals a missing or stale file.
+ */
+export async function seedAgentSessionPreamble(sessionId: string): Promise<void> {
+  const content = await readFile(join(agentSkillSourceDir(), 'preamble.sh'), 'utf-8');
+  const cacheDir = process.env.XDG_CACHE_HOME || join(homedir(), '.cache');
+  await mkdir(cacheDir, { recursive: true });
+  await writeFile(join(cacheDir, `codeman-agent-${sessionId}.sh`), content, { mode: 0o600 });
+}
+
+/**
+ * Refresh the USER-LEVEL skill copy (`~/.claude/skills/codeman`) IF one exists and is
+ * Codeman-managed. `codeman skill install` (no `--case`) writes that copy once, and
+ * unlike per-case copies (re-installed on every session create) nothing ever refreshed
+ * it, so it stayed at whatever version installed it. That matters because Claude Code
+ * loads the USER-LEVEL copy over a case's fresh one when both carry the name `codeman`:
+ * observed live 2026-08-14, an Aug 9 user copy (pre fast-path, pre lineage header)
+ * shadowed the current per-case injections, so every agent-driven spawn ran the old
+ * recipes, spawned workers serially, and lost their lineage arcs.
+ *
+ * Refresh-ONLY: an absent copy is not installed (the user never asked for a global
+ * copy), and foreign/symlink copies are refused by installAgentSkillInto itself.
+ */
+export async function refreshUserAgentSkill(): Promise<AgentSkillApplyResult | 'absent'> {
+  const skillDir = join(homedir(), '.claude', 'skills', 'codeman');
+  try {
+    const existing = await readFile(join(skillDir, 'SKILL.md'), 'utf-8');
+    if (!existing.includes(AGENT_SKILL_MARKER_PREFIX)) return 'foreign';
+  } catch {
+    return 'absent';
+  }
+  return installAgentSkillInto(skillDir);
+}
+
 /**
  * Remove a Codeman-managed skill copy from `skillDir`. Same ownership and symlink
  * refusals as the install path. Deletes only files the packaged source would have

src/web/routes/session-routes.ts

@@ -82,6 +82,8 @@ import {
   stripCaseEnvKeys,
   applyStatusLineConfig,
   applyAgentSkill,
+  refreshUserAgentSkill,
+  seedAgentSessionPreamble,
   refreshStaleCodemanHooks,
 } from '../../hooks-config.js';
 import { generateClaudeMd } from '../../templates/claude-md.js';
@@ -601,6 +603,13 @@ function abortOnClientHangUp(reply: FastifyReply): AbortController {
 async function injectAgentSkill(casePath: string): Promise<void> {
   const skillDir = join(casePath, '.claude', 'skills', 'codeman');
   try {
+    // Claude Code loads a same-named USER-LEVEL skill (`~/.claude/skills/codeman`,
+    // written once by `codeman skill install`) over the case copy injected below, so a
+    // stale user copy silently replaces every fresh injection (observed 2026-08-14: an
+    // old copy cost every spawned worker its lineage arc and the fast path). Keep it
+    // current on the same trigger. Refresh-only + marker-guarded; quiet on refusal,
+    // since a foreign user copy is the user's own authored skill, not a config error.
+    await refreshUserAgentSkill();
     const result = await applyAgentSkill(casePath, true);
     if (result === 'foreign') {
       console.warn(
@@ -913,6 +922,13 @@ export function registerSessionRoutes(
     ctx.store.incrementSessionsCreated();
     ctx.persistSessionState(session);
     await ctx.setupSessionListeners(session);
+    // Pre-seed the agent skill's preamble cache so its §0 bootstrap is a two-line
+    // loader (see seedAgentSessionPreamble). Local claude sessions only; best-effort.
+    if (mode === 'claude' && !remote && (await ctx.getAgentSkillEnabled())) {
+      await seedAgentSessionPreamble(session.id).catch((err: unknown) =>
+        console.warn(`[agent-skill] preamble seed failed for ${session.id}: ${getErrorMessage(err)}`)
+      );
+    }
     getLifecycleLog().log({ event: 'created', sessionId: session.id, name: session.name });
 
     // Use light state for broadcast + response — buffers are fetched on-demand via /terminal.
@@ -3016,6 +3032,13 @@ export function registerSessionRoutes(
     ctx.store.incrementSessionsCreated();
     ctx.persistSessionState(session);
     await ctx.setupSessionListeners(session);
+    // Pre-seed the agent skill's preamble cache so its §0 bootstrap is a two-line
+    // loader (see seedAgentSessionPreamble). Local claude sessions only; best-effort.
+    if (mode === 'claude' && !remote && !docker && (await ctx.getAgentSkillEnabled())) {
+      await seedAgentSessionPreamble(session.id).catch((err: unknown) =>
+        console.warn(`[agent-skill] preamble seed failed for ${session.id}: ${getErrorMessage(err)}`)
+      );
+    }
     getLifecycleLog().log({
       event: 'created',
       sessionId: session.id,

test/agent-skill.test.ts

@@ -11,11 +11,17 @@
  */
 
 import { describe, it, expect, beforeEach, afterEach } from 'vitest';
-import { mkdtemp, rm, mkdir, writeFile, readFile, symlink, readdir } from 'node:fs/promises';
+import { mkdtemp, rm, mkdir, writeFile, readFile, symlink, readdir, stat } from 'node:fs/promises';
 import { existsSync } from 'node:fs';
 import { join } from 'node:path';
-import { tmpdir } from 'node:os';
+import { tmpdir, homedir } from 'node:os';
-import { applyAgentSkill, installAgentSkillInto, removeAgentSkillFrom } from '../src/hooks-config.js';
+import {
+  applyAgentSkill,
+  installAgentSkillInto,
+  removeAgentSkillFrom,
+  refreshUserAgentSkill,
+  seedAgentSessionPreamble,
+} from '../src/hooks-config.js';
 
 const MARKER_PREFIX = '<!-- codeman-managed-agent-skill';
 
@@ -120,3 +126,86 @@ describe('removeAgentSkillFrom / applyAgentSkill(disabled)', () => {
     expect(await readFile(join(skillDir(), 'reference', 'my-notes.md'), 'utf-8')).toBe('mine\n');
   });
 });
+
+describe('preamble single-source (seed + §0 heredoc parity)', () => {
+  const packagedDir = join(process.cwd(), 'skills', 'codeman');
+
+  it("SKILL.md's §0 heredoc is byte-identical to the packaged preamble.sh", async () => {
+    const skillMd = await readFile(join(packagedDir, 'SKILL.md'), 'utf-8');
+    const openTag = "<<'PREAMBLE'\n";
+    const open = skillMd.indexOf(openTag);
+    expect(open).toBeGreaterThan(-1);
+    const start = open + openTag.length;
+    const end = skillMd.indexOf('\nPREAMBLE\n', start);
+    expect(end).toBeGreaterThan(start);
+    // slice(.., end + 1) keeps the final line's own newline.
+    const heredoc = skillMd.slice(start, end + 1);
+
+    // The server seeds preamble.sh while agents that paste §0 write the heredoc; any
+    // byte of drift between the two would make the §0 grep rewrite a seeded file (or
+    // worse, ship different behavior depending on which path wrote it).
+    const preamble = await readFile(join(packagedDir, 'preamble.sh'), 'utf-8');
+    expect(preamble).toBe(heredoc);
+  });
+
+  it('seedAgentSessionPreamble writes the stamped preamble to the XDG cache path, 0600', async () => {
+    const prevXdg = process.env.XDG_CACHE_HOME;
+    const cacheDir = join(casePath, 'xdg-cache');
+    process.env.XDG_CACHE_HOME = cacheDir;
+    try {
+      await seedAgentSessionPreamble('seed-test-session');
+      const target = join(cacheDir, 'codeman-agent-seed-test-session.sh');
+      const content = await readFile(target, 'utf-8');
+      expect(content.startsWith('# ---- Codeman agent preamble')).toBe(true);
+      expect(content).toMatch(/\nCODEMAN_PREAMBLE=\d+\.\d+\.\d+\n$/);
+      expect((await stat(target)).mode & 0o777).toBe(0o600);
+    } finally {
+      if (prevXdg === undefined) delete process.env.XDG_CACHE_HOME;
+      else process.env.XDG_CACHE_HOME = prevXdg;
+    }
+  });
+
+  it('seedAgentSessionPreamble falls back to ~/.cache when XDG_CACHE_HOME is unset', async () => {
+    const prevXdg = process.env.XDG_CACHE_HOME;
+    delete process.env.XDG_CACHE_HOME;
+    try {
+      await seedAgentSessionPreamble('seed-home-session');
+      // setup.ts points HOME at a per-file fixture, so this never touches the real ~.
+      const target = join(homedir(), '.cache', 'codeman-agent-seed-home-session.sh');
+      expect(existsSync(target)).toBe(true);
+    } finally {
+      if (prevXdg !== undefined) process.env.XDG_CACHE_HOME = prevXdg;
+    }
+  });
+});
+
+describe('refreshUserAgentSkill (the user-level copy must not rot)', () => {
+  const userSkillDir = () => join(homedir(), '.claude', 'skills', 'codeman');
+
+  it('reports absent and installs nothing when there is no user-level copy', async () => {
+    expect(await refreshUserAgentSkill()).toBe('absent');
+    expect(existsSync(userSkillDir())).toBe(false);
+  });
+
+  it('refreshes a stale Codeman-managed user copy back to the packaged content', async () => {
+    await mkdir(userSkillDir(), { recursive: true });
+    // An old injected version: different content, marker intact. This is the exact
+    // shape that shadowed every fresh per-case injection on 2026-08-14.
+    await writeFile(join(userSkillDir(), 'SKILL.md'), `old skill body\n\n${MARKER_PREFIX}: installed by Codeman -->\n`);
+
+    expect(await refreshUserAgentSkill()).toBe('refreshed');
+    const refreshed = await readFile(join(userSkillDir(), 'SKILL.md'), 'utf-8');
+    expect(refreshed.startsWith('---\nname: codeman')).toBe(true);
+    expect(existsSync(join(userSkillDir(), 'reference', 'endpoints.md'))).toBe(true);
+
+    // And a second run settles to unchanged.
+    expect(await refreshUserAgentSkill()).toBe('unchanged');
+  });
+
+  it("leaves a user's own (unmarked) skill alone", async () => {
+    await mkdir(userSkillDir(), { recursive: true });
+    await writeFile(join(userSkillDir(), 'SKILL.md'), 'my own codeman skill\n');
+    expect(await refreshUserAgentSkill()).toBe('foreign');
+    expect(await readFile(join(userSkillDir(), 'SKILL.md'), 'utf-8')).toBe('my own codeman skill\n');
+  });
+});