Problem

session-end.js (Stop hook) silently corrupts the persisted session summary when a user message contains a $-sequence ($&, $$, $\``, $') — which is common in dev work (regexes, PASS=$1, prices like $5`, shell snippets).

Root cause

The regenerated summary block embeds raw user-message text, and is passed as the replacement argument to String.prototype.replace (lines 259 & 265):

updatedContent = updatedContent.replace(markerRegex, summaryBlock); // summaryBlock has user text

In a replacement string, $& = the whole match, $$ = $, etc. buildSummarySection escapes newlines and backticks but not $. So on any repeat Stop (when the file already has the summary markers), a user message like release $& fallback makes $& re-inject the entire matched old block, duplicating the summary markers and dropping the user's text.

Verified corruption on a release $& fallback $$ done message (markers duplicated, $$ → $):

### Tasks
- release <!-- ECC:SUMMARY:START -->
## Session Summary
### Tasks
- old task
<!-- ECC:SUMMARY:END --> fallback $ done

Fix

Use function replacers (() => summaryBlock) at both rewrite sites — a function replacement is treated literally, so no $-interpretation occurs. (Equivalent to escaping $→$$; the function form is cleaner and covers all sequences.)

Tests

Adds tests/hooks/session-end.test.js — an end-to-end regression test (seeds a marker'd session file + a transcript whose user message contains $&/$$, runs the hook, asserts the text survives verbatim and the markers appear exactly once). Confirmed it fails on the current code and passes with the fix.

Summary by cubic

Fixes summary corruption in the session-end hook when user messages include $-sequences (e.g., $&, $$). Replacements now treat the summary block literally so user text is preserved and markers appear once.

• Bug Fixes
  • Use function replacers for both summary rewrite paths to avoid $ interpretation by String.prototype.replace.
  • Add an end-to-end regression test that verifies $&, $$, $', and `$`` are preserved and that the summary marker pair appears exactly once.

^{Written for commit d5c3e81. Summary will update on new commits.}

Summary by CodeRabbit

• Bug Fixes

  • Fixed an issue where certain special characters in user messages could interfere with session summary generation and storage.

• Tests

  • Added regression tests to verify session summary reliability with various message content.