fix(hooks): ISASync refreshes the ISA body hash on Read

LifeOS/install/hooks/ISASync.hook.ts

@@ -1,6 +1,6 @@
 #!/usr/bin/env bun
 /**
- * @version 1.5.0
+ * @version 1.5.1
  * ISASync.hook.ts — ISA → work.json sync via PostToolUse
  *
  * TRIGGER: PostToolUse (Write, Edit, MultiEdit, Read)
@@ -29,6 +29,15 @@
  * because the strip was the last derived-state line the model self-computed.
  * No ISA write → no block → no strip: an unregistered run can no longer
  * claim a state the board doesn't show.
+ *
+ * v1.5.1 (Read refreshes the body hash): the Read branch now calls
+ * refreshBodyHashBySlug() before the heartbeat bump, so the registry's
+ * bodyHash matches the file the model just read. Read still never writes the
+ * ISA — only the registry's observation of it. Writes that bypass
+ * Write/Edit/MultiEdit (Bash heredocs, subagents, git, this hook's own
+ * Decisions append) used to leave that hash stale, and the next edit — even a
+ * frontmatter-only one, which hashBody() excludes — read as a body change and
+ * rewound a complete ISA to `learn`.
  */
 
 import { readFileSync, existsSync } from 'fs';
@@ -40,6 +49,7 @@ import {
   syncToWorkJson,
   readRegistry,
   bumpLastToolActivityBySlug,
+  refreshBodyHashBySlug,
   ARTIFACT_FILENAME,
   LEGACY_ARTIFACT_FILENAME,
 } from './lib/isa-utils';
@@ -72,10 +82,18 @@ async function main(): Promise<string | null> {
   const isWorkISA = filePath.includes('MEMORY/WORK/');
 
   // v6.9.0: Read trigger — bump heartbeat on the slug, rebind UUID, debounced.
-  // No file write-back, no rewind. Read alone never mutates the ISA.
+  // No file write-back, no rewind. Read alone never mutates the ISA. It does
+  // refresh the registry's bodyHash from disk, so the Edit that follows a Read
+  // compares against the body as it was just observed, not against whatever
+  // Write/Edit last saw — Bash heredocs, subagents, git and hook appends all
+  // write ISAs without firing this hook, and a stale hash turned a
+  // frontmatter-only edit on a complete ISA into a false rewind (2026-09-14).
   if (toolName === 'Read') {
     const slugMatch = filePath.match(/MEMORY\/WORK\/([^/]+)\//);
-    if (slugMatch) bumpLastToolActivityBySlug(slugMatch[1], input.session_id);
+    if (slugMatch) {
+      refreshBodyHashBySlug(slugMatch[1], filePath);
+      bumpLastToolActivityBySlug(slugMatch[1], input.session_id);
+    }
     return null;
   }
 

LifeOS/install/hooks/hooks.json

@@ -116,6 +116,10 @@
           {
             "type": "command",
             "command": "$HOME/.claude/hooks/ISAStaleWriteGuard.hook.ts"
+          },
+          {
+            "type": "command",
+            "command": "$HOME/.claude/hooks/ISASync.hook.ts"
           }
         ]
       },

LifeOS/install/hooks/lib/isa-utils.ts

@@ -17,7 +17,7 @@
 // module reads ISA.md first and falls back to PRD.md for sessions created
 // before the rename. New sessions always write ISA.md.
 
-import { writeFileSync, readdirSync, statSync, existsSync, mkdirSync, appendFileSync } from 'fs';
+import { writeFileSync, readFileSync, readdirSync, statSync, existsSync, mkdirSync, appendFileSync } from 'fs';
 import { join, basename } from 'path';
 import { createHash } from 'crypto';
 import { paiPath } from './paths';
@@ -1077,6 +1077,35 @@ export function bumpLastToolActivity(filePath: string): boolean {
   return bumpLastToolActivityBySlug(slug);
 }
 
+/**
+ * Refresh the registry's view of an ISA body from disk without touching the ISA
+ * or its phase. Called on Read: the Edit tool requires a Read first, so after
+ * this the next Edit's `bodyChanged` measures only that edit's own delta.
+ * Without it, anything that wrote the ISA outside Write/Edit (a Bash heredoc,
+ * a subagent, git, a hook's own append) left `bodyHash` stale, and the next
+ * frontmatter-only edit on a complete ISA read as a body change and rewound it
+ * to `learn` (three false rewinds on one ISA, 2026-09-14). Never debounced,
+ * never gated on phase — a stale hash is wrong at any age.
+ */
+export function refreshBodyHashBySlug(slug: string, isaPath: string): boolean {
+  if (!slug || !isaPath) return false;
+  try {
+    if (!existsSync(isaPath)) return false;
+    const registry = readRegistry();
+    const session = registry.sessions[slug];
+    if (!session) return false;
+    const content = readFileSync(isaPath, 'utf-8');
+    const bodyHash = hashBody(content);
+    if (session.bodyHash === bodyHash && session.lastBodySize === content.length) return false;
+    session.bodyHash = bodyHash;
+    session.lastBodySize = content.length;
+    writeRegistry(registry, 'refreshBodyHashBySlug');
+    return true;
+  } catch {
+    return false;
+  }
+}
+
 /**
  * v6.9.0: Bump `lastToolActivity` by slug (not by sessionUUID). Used by the
  * Read-trigger path in ISASync — a fresh session UUID reading an ISA still