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Integration · Grok Build · T4

Grok Build as a T4 Handoff Destination | Reinstate

Grok Build is T4: a read-only local index, a handoff source, a handoff destination, and same-vendor native resume through the vendor's own CLI. A handoff into Grok starts a new session and is never a cross-agent resume. Reinstate does not sync Grok sessions.

Last verified
Current release
v0.6.0
Release status
v0.6.0 stable · native Windows x64 tagged-artifact acceptance PASS (215/215 required rows, docs/testing/results/2026-09-09-windows-v060rc8.md) under the single-platform waiver (ADR 0005) · Apple Silicon macOS acceptance deferred to #403 · supersedes v0.5.1

Grok Build support at a glance

Tier
T4 Handoff destination
Storage family
F1 home tree
Verified version range
1.0.5 – 1.0.13
Encrypted sync (T5)
Not supported

T4 means rein handoff <session> --to grok starts a new Grok session with grok --session-id <uuid>, on top of the T3rein resume grok:<id> and the T2rein handoff --from grok. Grok Build is not a T5 sync agent.

What T4 includes

  • T1 read-only discovery, search, and inspect of local Grok Build sessions.
  • T2 structured handoff from Grok Build into a new Claude Code or Codex session.
  • T3 same-vendor rein resume and rein fork, the latter throughgrok --resume <uuid> --fork-session.
  • T4 structured handoff into Grok Build. That starts a new session and is never a cross-agent resume: Reinstate does not reconstruct source history in Grok.
  • A bounded grok --version probe with a fail-closed range of 1.0.5 – 1.0.13.
  • Fail-closed behavior on an unrecognized layout or version (exit code 5).

What T4 excludes

  • No rein push / rein pull of Grok sessions.
  • No write into Grok's session store.
  • No resume of a session whose recorded id is not a UUID. grok --resume also accepts a session title, and titles are neither unique nor stable, so such a session stays read-only rather than being addressed by name.

Native resume is same-vendor: it launches Grok's own CLI against Grok's own session.

A handoff starts a new destination session in either direction. It does not reconstruct vendor history or translate a transcript between vendors.

Grok Build has documented repository-content upload behaviour, so a handoff from or into it always runs capsule redaction, always prints that warning, and refuses--no-redact with exit 2.

Evidence

Committed fixtures live under testdata/sessionindex/grok andtestdata/handoff/grok, and the version range was measured from the real binary. The resume journeys T3 rests on and the destination journey T4 rests on are both recorded, on macOS and on native Windows. See theGrok storage pageand the tier matrix.