#1885 cross-session state bus

Each claude agents session writes its own distilled state to a known file path. Any other session can read it with one tool call. No wrappers around the native CLI; no parsing of CC's internal JSONL.

❌ Before — "did the agent ship?"

$ git -C platform log --oneline -5
$ git -C platform reflog | head -5
$ git -C platform log -1 --format='%cI %s'
$ gh pr list --repo y/p --head feat/x
$ gh pr checks 3703 --repo y/p
$ ls ~/.claude/projects/-…/sessions/

⏱ 6 tool calls · 200+ lines · context bloated
   Operator hesitates → late detection → bigger blast

✅ After

$ cat ~/.claude/state/orchestkit/platform/*.json
{
  "repo": "platform",
  "status": "running",
  "last_heartbeat": "2026-05-20T17:42:14Z",
  "last_commit": {
    "sha": "3a99c20",
    "msg": "feat(api): canonical seed-data migration"
  },
  "last_push": { "branch": "feat/x", "ref": "3a99c20" },
  "last_pr":   { "number": 3703, "url": "…", "state": "open" }
}

⏱ 1 tool call · structured JSON · zero grep

What gets wired (2 hooks, 1 lib)

src/hooks/src/lib/session-state.ts                       ← schema + atomic I/O
src/hooks/src/posttool/bash/session-heartbeat-publisher  ← PostToolUse[Bash], async
src/hooks/src/stop/session-heartbeat-finalizer           ← SessionEnd, sync dispatcher

PUBLISHER fires on EVERY Bash, no-ops on non-structural commands.
Matches: git commit | git push | gh pr create|merge|ready
Writes to: ~/.claude/state/orchestkit/<repo>/<sid>.json (atomic, tmp+rename)

FINALIZER runs once at SessionEnd to mark status=completed.
If session is killed unsafely, last_heartbeat goes stale (proxy for stopped).

Fleet view (no new tool — plain shell)

$ ls ~/.claude/state/orchestkit/*/*.json | xargs cat | jq -s \
    'map({ repo, status, last_pr: .last_pr.number, last_commit: .last_commit.msg })'
[
  { "repo": "orchestkit",    "status": "running",   "last_pr": 1900, … },
  { "repo": "portfolio",     "status": "running",   "last_pr": 223,  … },
  { "repo": "platform",      "status": "running",   "last_pr": 3703, … },
  { "repo": "sanity-agency", "status": "completed", "last_pr": 16,   … }
]

Design rules (this is the #1890 takeaway applied)

❌ NOT a wrapper around claude agents (that was agents-view)
❌ NOT a parser of CC's transcript JSONL (would couple to internals)
❌ NOT a new skill, CLI, or MCP — file format IS the contract
✅ Each session writes ONLY its own file
✅ Atomic tmp+rename — readers never see a half-written file
✅ Hooks log on debug only — never blocks Claude

Test coverage (Layer 1 + Layer 5)