gz obpi brief-drift

Overview

gz obpi brief-drift runs the OBPI-0.0.37-05 reconciliation engine to measure drift between an OBPI brief and the project tree across five dimensions — allowlist, discovery checklist, verification verbs, REQ count, and citation tuples (invariant CIC-2, brief↔reality coherence). Every run, --dry-run included, appends a brief_reconciled ledger event, plus brief_reconcile_drift_detected when the result gates.

What gates depends on the brief's status::

• Terminal (list in step 1): deltas are reported, nothing gates.
• Draft: allowlisted paths missing on disk and unresolved gz verbs are reported but do not gate, because they name what the OBPI will create. A Discovery Checklist path still gates unless a sibling OBPI's Allowed Paths create it; stale citations still gate.
• Live (Active, in_progress): allowlist, discovery, verification and citation drift all gate.

The REQ count delta never gates; it is reported for information.

When to Use

• Before Stage 2 implementation, to confirm a brief still matches project shape.
• Before OBPI completion, to confirm zero residual drift.
• Whenever a brief's allowlist or REQ set looks stale relative to the code.

Workflow

1. Confirm the target OBPI id and that its brief file exists. Check its status: first — a terminal brief (Completed, attested_completed, Validated, Superseded, archived, Promoted, Abandoned, Withdrawn) reports deltas but never gates: has_drift is always false and the run exits 0. Its deltas read as "what moved since this shipped", never as a repair worklist. --apply on one is refused — exit 3, nothing written, no ledger event, --dry-run included — because the amendment would rewrite a sealed record under an attestation no operator can honestly give (GHI #707, #1115).
2. Run uv run gz obpi brief-drift <OBPI-ID> to report per-dimension deltas. Exit 0 means clean; exit 3 means drift. On a live (non-terminal) brief only.
3. If drift is real, preview with uv run gz obpi brief-drift <OBPI-ID> --apply --dry-run. The preview writes nothing to the brief and lists every line --apply would add or remove (planned_amendments under --json). Show that list to the operator: it is the amendment they attest in step 4.
4. Apply with uv run gz obpi brief-drift <OBPI-ID> --apply. --attestor takes a handle, never a real name, and defaults to authorship.attestor_handle in .gzkit.json; --apply refuses without one. The write adds each src/ module that the brief's REQ-covering tests import, that sits beside an allowlisted src/ path, and that the brief neither allows nor denies — to frontmatter allowlist: on a structured brief, under ## Allowed Paths on a legacy one — and records unresolved verbs and REQ identity drift under ## Tracked Defects, never rewriting them. Allowlisted paths missing on disk, discovery and citation drift are not repaired. --apply re-measures the brief after writing and reports that second measurement, so the exit contract in step 2 binds here too: exit 3 means drift survived the amendment (--apply repairs the allowlist dimension only), not that the write failed.

Validation

• The exit code already reflects the post-amendment brief — a re-run is a confirmation, not the measurement. Confirm the expected dimensions now report zero (or the residual is intentional and tracked).
• Confirm the brief_reconciled ledger event was emitted (and brief_reconcile_drift_detected when drift was present).

Example

Use $gz-obpi-brief-drift to reconcile an OBPI brief against project state before completion.