W5.2: /sync-gbrain is the only writer of the CLAUDE.md search-guidance block

setup-gbrain's claude-md-persist section stops writing its own
'## GBrain Search Guidance' block, which also removes the false
'auto-syncs on every gstack skill start' text (s09 H15; s09 H14 decided).
Step 10 offers to run /sync-gbrain now and names it otherwise. Test sweep:
only skill-e2e-sync-gbrain-readiness references the heading, and it checks
the block /sync-gbrain writes, so no test changes.

setup-gbrain/SKILL.md.tmpl

@@ -416,8 +416,9 @@ For Paths 1, 2a, 2b, 3, run the ingest gate:
 ## Step 8: Persist `## GBrain Configuration` in CLAUDE.md
 
 CLAUDE.md is the audit trail: after a successful setup, persist the
-configuration block. The exact block formats (remote-http vs local-stdio) and
-the post-Step-9 Search Guidance write live in the claude-md-persist section.
+configuration block. The exact block formats (remote-http vs local-stdio) live
+in the claude-md-persist section. The search-guidance block is written only by
+`/sync-gbrain` (Step 10 offers it).
 
 {{SECTION:claude-md-persist}}
 
@@ -610,6 +611,15 @@ There is no automatic restore: with brain-sync enabled, the brain remote holds
 curated artifacts as markdown + git, recoverable via `gbrain import` from a
 clone.
 
+### Next: `/sync-gbrain`
+
+This skill does not write the `## GBrain Search Guidance` block in CLAUDE.md;
+`/sync-gbrain` writes it once this repo's code index answers a read. Unless
+the verdict is RED, AskUserQuestion: "Run `/sync-gbrain` now to index this
+repo and add the search guidance to CLAUDE.md?" A) Run it now (read and
+follow the sync-gbrain skill) B) Later. If B, or with `SESSION_KIND: spawned`
+or `headless`, end by naming `/sync-gbrain` as the next step.
+
 ---
 
 ## `/setup-gbrain --cleanup-orphans`

setup-gbrain/sections/claude-md-persist.md.tmpl

@@ -32,46 +32,7 @@ in to git in many projects). It lives only in `~/.claude.json` where
 - Current repo policy: {read-write|read-only|deny|unset}
 ```
 
-**After Step 9 (smoke test) passes, also write the `## GBrain Search Guidance`
-block** so the coding agent learns when to prefer `gbrain` over Grep. This
-block is gated on the smoke test passing — write the Configuration block
-first (so the user knows what state they're in even if the smoke test fails),
-then return here after Step 9 and write the guidance block only if smoke
-test succeeded.
-
-When Step 9 passes, find-and-replace (or append) this block. Use HTML-comment
-delimiters so removal regex is unambiguous and never eats user content. The
-block content is machine-AGNOSTIC — no engine type, no page counts, no
-last-sync time. Machine state stays in the Configuration block above.
-
-```markdown
-## GBrain Search Guidance (configured by /sync-gbrain)
-<!-- gstack-gbrain-search-guidance:start -->
-
-GBrain is set up and synced on this machine. The agent should prefer gbrain
-over Grep when the question is semantic or when you don't know the exact
-identifier yet. Two indexed corpora available via the `gbrain` CLI:
-- This repo's code (registered as `gstack-code-<repo>` source).
-- `~/.gstack/` curated memory (registered as `gstack-brain-<user>` source via
-  the existing federation pipeline).
-
-Prefer gbrain when:
-- "Where is X handled?" / semantic intent, no exact string yet:
-    `gbrain search "<terms>"` or `gbrain query "<question>"`
-- "Where is symbol Y defined?" / symbol-based code questions:
-    `gbrain code-def <symbol>` or `gbrain code-refs <symbol>`
-- "What calls Y?" / "What does Y depend on?":
-    `gbrain code-callers <symbol>` / `gbrain code-callees <symbol>`
-- "What did we decide last time?" / past plans, retros, learnings:
-    `gbrain search "<terms>" --source gstack-brain-<user>`
-
-Grep is still right for known exact strings, regex, multiline patterns, and
-file globs. The brain auto-syncs incrementally on every gstack skill start.
-Run `/sync-gbrain` to force-refresh, `/sync-gbrain --full` for full reindex.
-
-<!-- gstack-gbrain-search-guidance:end -->
-```
-
-If Step 9 smoke test fails, skip the guidance block write entirely. The user's
-next `/sync-gbrain` run will re-evaluate capability and write the block when
-the round-trip works.
+Do not write a `## GBrain Search Guidance` block here. `/sync-gbrain` is its
+only writer: it writes the block after its read check confirms this repo's
+code index answers, and replaces any older block under the same heading.
+Step 10 offers to run `/sync-gbrain`.

setup-gbrain/sections/manifest.json

@@ -25,8 +25,8 @@
     {
       "id": "claude-md-persist",
       "file": "claude-md-persist.md",
-      "title": "Step 8: persist the GBrain Configuration + Search Guidance blocks in CLAUDE.md",
-      "trigger": "persisting the Step 8 `## GBrain Configuration` block to CLAUDE.md (and the Search Guidance block after Step 9 passes)"
+      "title": "Step 8: persist the GBrain Configuration block in CLAUDE.md",
+      "trigger": "persisting the Step 8 `## GBrain Configuration` block to CLAUDE.md"
     }
   ]
 }