job7 capitalize: BDR-057, BDR-026 update, LRN-108, journal

BDR-057: secrets by reference not by value; redact at capture, not just at
rest. Documents the two-part job7 posture (MCP ${VAR} expansion + rtk-rewrite
env-dump redaction) and flags the unreconciled contradiction with job6's
same-day (wrong) finding that ${VAR} expansion was unsupported at user scope.

BDR-026 updated: the backup-vector incident (2026-07-02) is closed at the
source rather than by repeated scrubbing — every native auto-backup taken
while the live file held the plaintext value was a fresh leak, so scrubbing
existing backups alone would have recurred forever.

LRN-108: `claude mcp add --env KEY=value` writes the value literally —
double- vs single-quoting around `${VAR}` is the entire difference between
a reference and a plaintext-forever config. The natural way to type the
flag (bash-expand it first) is exactly the trap.

Also refreshed .audit/scan-secrets-claude-home.json to the post-purge state
(15 residual hits, down from 18 pre-D).

.claude/memory/decisions.md

@@ -77,6 +77,7 @@ rules:
 | BDR-054 | 2026-07-06 | supersede BDR-038 NEXT.sh/hand-back artifacts — shipped impl removed both (52f6678, LRN-102) | accepted |
 | BDR-055 | 2026-07-07 | job5: delete memory-commit/doc-commit `pending` verbs — v2 hook rejected (BDR-037), J4-17 closed MOOT | accepted |
 | BDR-056 | 2026-07-07 | job6: deps policy = latest gated by integration, not KEEP-PINNED by default | accepted |
+| BDR-057 | 2026-07-07 | job7: secrets by reference not by value; redact at capture, not just at rest | accepted |
 
 ---
 
@@ -486,6 +487,7 @@ rules:
   - Scripts read `~/.claude/.env` directly — makes the symlink redundant but rewrites every read path and loses repo-local visibility.
 - **Reference**: `link.sh` `link_env()`, `.gitignore`, `lib/toggle-external.sh`, `install-plugins.sh`, `.env.example`, commits 131d0bc / f9cc866. Linked to [[BDR-025]] (magic's `MAGIC_API_KEY`, consumed by the gate's required-but-manual class).
 - **Update 2026-07-02 (incident — copies of secrets)**: `claude mcp add --env` MATERIALIZES the key into `~/.claude.json` (`mcpServers.magic.env`) — a 2nd live copy OUTSIDE the `~/.claude/.env` canonical and outside the repo deny rules' reach. An audit query printed it into a session transcript → key rotated (21st.dev). Rule: secrets have COPIES (tool configs, transcripts, caches) — protect/audit the copies, not just the canonical; when inspecting MCP config, filter env fields (`jq 'del(.. | .env?)'`). Same audit: `~/.claude/.env` hardened 0664→0600.
+- **Update 2026-07-07 (job7 — backup vector closed)**: the `~/.claude.json` copy from the 2026-07-02 incident kept re-leaking into `~/.claude/backups/.claude.json.backup.*` (native Claude Code auto-backup, ring-buffer of 5, plaintext each time) — every backup taken while the live file held the value was a fresh copy, so scrubbing existing backups alone would have recurred forever. Closed at the source instead ([[BDR-057]]): `~/.claude.json`'s `mcpServers.magic.env.API_KEY` rewritten to `"${MAGIC_API_KEY}"` (Claude Code `${VAR}` expansion, confirmed supported at user scope), `lib/toggle-external.sh` writes the reference form for future `enable magic` runs, var reaches `claude` only via a scoped `~/.bashrc` wrapper (never the ambient shell). New backups taken after the fix carry the reference, not the value — confirmed empirically (2 of 5 rotating backups mid-fix still had the old value; scrubbed once, not expected to recur). MAGIC_API_KEY itself still needs rotation (this closes the storage vector, not the already-exposed value).
 
 ---
 
@@ -875,3 +877,15 @@ rules:
 - **Alternatives rejected**: KEEP-PINNED unless CVE (job6-batch-3 default) — optimizes for zero-gate-work, pays for it by sitting on fail-open security guards and data-loss bugs with no formal CVE filed; blanket "always latest, no gate" — the gsd-pi break shows why the gate stays mandatory, this is not a license to skip it.
 - **Caveats**: not every dep took the full pull — graphifyy's hook-guard rewrite (a config-protected file) was surfaced with a diff and the user declined to adopt it this round (binary upgraded, hook install skipped); MCP magic version pin was declined by user call. Policy is "latest, gated", not "latest, no exceptions".
 - **Reference**: `.audit/job6-report.md`; commits `b4896c9` (gsd-pi), `2813e55` (gstack), `00c97bc` (docs); [[LRN-107]] (secrets-subagent value-copy ban, same job's incident).
+
+---
+
+## BDR-057 — job7: secrets by reference not by value; redact at capture, not just at rest
+
+- **Date**: 2026-07-07
+- **Status**: accepted
+- **Decision**: two-part posture from the job7 triage (`.audit/job7/ALL-REDACTED.json`, 5+ leak classes across `~/.claude` and repos). (1) Wherever the consuming tool supports it, wire secrets BY REFERENCE (`${VAR}` expansion), not by value — closed the concrete case: `lib/toggle-external.sh`'s `claude mcp add magic --env API_KEY="$MAGIC_API_KEY"` materialized the key as plaintext into `~/.claude.json` (a 2nd copy outside the `~/.claude/.env` canonical); fixed to `--env 'API_KEY=${MAGIC_API_KEY}'`, with the var reaching `claude` only via a scoped `~/.bashrc` wrapper function (subshell + exec — never the ambient shell). (2) Redact AT THE CAPTURE POINT, not just after the fact: `hooks/rtk-rewrite.sh` now appends a redaction pipe to bare `printenv`/`env` dumps before they can reach stdout/the transcript (the GITEA leak's actual vector), instead of relying solely on scrubbing artifacts after the fact.
+- **Why**: the job6 incident ([[LRN-107]]) and the GITEA leak both trace back to a secret VALUE existing somewhere it didn't strictly need to (a config field, a raw env dump) rather than a reference/redacted form. Fixing storage-at-rest (scrub backups) treats the symptom and must be redone every time a new copy appears (5 rotating `.claude.json.backup.*` files, 2 of 5 still had it live mid-job7 despite the canonical fix already applied) — fixing the SOURCE (don't materialize the value; redact before the dump leaves the process) is the only version that doesn't need repeating.
+- **Alternatives rejected**: scrub-only (chosen as the fallback in job7's own instructions if reference-by-value support were absent) — verified Claude Code DOES support `${VAR}` expansion in `mcpServers` config (user + project scope, `env`/`command`/`args`/`url`/`headers` fields — code.claude.com/docs/en/mcp.md), so the reference form was available and preferred; global `export MAGIC_API_KEY` in `~/.bashrc` — works but broadens the secret's exposure to every subprocess of every shell session, defeating the point of the redaction hook (rejected by user in favor of the scoped wrapper).
+- **Reference**: `lib/toggle-external.sh:191-192`, `hooks/rtk-rewrite.sh`, `README.md` "Adding an MCP server that needs a secret", `.gitleaks.toml`, `lib/gitflow.sh` `_gitflow_emit_pre_commit`, `Makefile` `scan-secrets`; commits `b9300c3`/`3340c7d`/`17bdd08`/`5d5b386`. Linked to [[BDR-026]] (canonical vault this closes a leak vector against), [[LRN-108]] (the `claude mcp add --env` trap).
+- **Caveat — contradicts job6's own finding same day**: job6's journal (2026-07-07, earlier same day) states "`${VAR}` env-expansion confirmed unsupported at `~/.claude.json` user scope after 2 rounds of sourced doc lookup". job7's doc lookup (claude-code-guide agent, same day) found it IS supported at user scope, citing code.claude.com/docs/en/mcp.md + a v2.1.161 changelog entry. Not reconciled — could be a version bump between the two lookups, or job6's research being wrong. The `${MAGIC_API_KEY}` rewrite is live (`claude mcp list` recognizes the reference and reports the var missing, which requires the CLI to have at least PARSED the `${...}` syntax) but full end-to-end confirmation (restart terminal + Claude Code, verify magic MCP reconnects) is still a residual the user needs to do — see BDR-057's own commit message.