fix: address self-review findings

commands/resume-session.md

@@ -30,8 +30,9 @@ This command is the counterpart to `/save-session`.
 If no argument provided:
 
 1. Check `~/.claude/session-data/`
-2. Pick the most recently modified `*-session.tmp` file
-3. If the folder does not exist or has no matching files, tell the user:
+2. Read the matching `*-session.tmp` candidates and apply the candidate ranking below
+3. Load the highest-ranked candidate
+4. If the folder does not exist or has no eligible matching files, tell the user:
    ```
    No session files found in ~/.claude/session-data/
    Run /save-session at the end of a session to create one.
@@ -42,11 +43,30 @@ If an argument is provided:
 
 - If it looks like a date (`YYYY-MM-DD`), search `~/.claude/session-data/` first, then the legacy
   `~/.claude/sessions/`, for files matching `YYYY-MM-DD-session.tmp` (legacy format) or
-  `YYYY-MM-DD-<shortid>-session.tmp` (current format)
-  and load the most recently modified variant for that date
-- If it looks like a file path, read that file directly
+  `YYYY-MM-DD-<shortid>-session.tmp` (current format), apply the candidate ranking below across
+  all matches, and load the highest-ranked candidate for that date
+- If it looks like a file path, read exactly that file directly. Do not apply candidate ranking or
+  substitute a different file, even if the requested file is empty or another file is newer
 - If not found, report clearly and stop
 
+#### Candidate ranking for implicit and date-based lookup
+
+Rank only automatically discovered candidates. Never use this ranking for an explicit file path.
+
+1. Reject files that are unreadable, empty, whitespace-only, or contain only headings, metadata,
+   separators, and placeholder values such as `[Session context goes here]`, `- [ ]`, a lone `-`,
+   or `[relevant files]`.
+2. Reject generated summaries with only one task and no populated files-modified, tools-used,
+   completed, in-progress, notes, or context-to-load content. This structural rule filters
+   one-message summarizer echoes without depending on any particular prompt text.
+3. Keep candidates with substantive populated content: completed work, in-progress work, concrete
+   next-session notes, concrete context paths, multiple tasks, modified files, or tools used.
+4. Among eligible substantive candidates, prefer the newest modification time.
+5. If modification times are equal, prefer more populated sections, then more non-placeholder
+   content, then larger byte size, then the lexicographically smaller resolved path. Count populated
+   sections and content only after removing headings, metadata, separators, and placeholder text.
+   These final tie-breaks make selection deterministic.
+
 ### Step 2: Read the entire session file
 
 Read the complete file. Do not summarize yet.
@@ -96,7 +116,9 @@ If no next step is defined — ask the user where to start, and optionally sugge
 ## Edge Cases
 
 **Multiple sessions for the same date** (`2024-01-15-session.tmp`, `2024-01-15-abc123de-session.tmp`):
-Load the most recently modified matching file for that date, regardless of whether it uses the legacy no-id format or the current short-id format.
+Apply the candidate ranking across every matching legacy and current-format file. A substantive
+session must win over a newer placeholder or one-message summarizer echo; modification time decides
+between eligible candidates.
 
 **Session file references files that no longer exist:**
 Note this during the briefing — "WARNING: `path/to/file.ts` referenced in session but not found on disk."
@@ -108,7 +130,10 @@ Note the gap — "WARNING: This session is from N days ago (threshold: 7 days).
 Read it and follow the same briefing process — the format is the same regardless of source.
 
 **Session file is empty or malformed:**
-Report: "Session file found but appears empty or unreadable. You may need to create a new one with /save-session."
+For implicit or date-based discovery, reject it and continue ranking the remaining candidates. If no
+eligible candidate remains, report: "Session files were found but appear empty or unreadable. You may
+need to create a new one with /save-session." For an explicit path, report that the requested file is
+empty or unreadable without loading a substitute.
 
 ---
 

scripts/hooks/session-end.js

@@ -94,6 +94,10 @@ function extractSessionSummary(transcriptPath) {
   };
 }
 
+function isLowSubstanceTranscript(summary) {
+  return summary.totalMessages === 1 && summary.toolsUsed.length === 0 && summary.filesModified.length === 0;
+}
+
 // Read hook input from stdin (Claude Code provides transcript_path via stdin JSON)
 const MAX_STDIN = 1024 * 1024;
 let stdinData = '';
@@ -181,6 +185,24 @@ async function main() {
     }
   }
 
+  // Classify known transcripts before resolving session metadata or touching the
+  // session directory. Missing, unreadable, or unparseable transcript data keeps
+  // the established fallback behavior because it cannot be classified reliably.
+  let summary = null;
+  let transcriptExists = false;
+  if (transcriptPath) {
+    transcriptExists = fs.existsSync(transcriptPath);
+    if (transcriptExists) {
+      summary = extractSessionSummary(transcriptPath);
+      if (summary && isLowSubstanceTranscript(summary)) {
+        log('[SessionEnd] Skipped one-message session without tool or file activity');
+        return;
+      }
+    } else {
+      log(`[SessionEnd] Transcript not found: ${transcriptPath}`);
+    }
+  }
+
   const sessionsDir = getSessionsDir();
   const today = getDateString();
   // Derive shortId from transcript_path UUID when available, using the SAME
@@ -211,21 +233,10 @@ async function main() {
 
   const currentTime = getTimeString();
 
-  // Try to extract summary from transcript
-  let summary = null;
-
-  if (transcriptPath) {
-    if (fs.existsSync(transcriptPath)) {
-      summary = extractSessionSummary(transcriptPath);
-    } else {
-      log(`[SessionEnd] Transcript not found: ${transcriptPath}`);
-    }
-  }
-
   // Decide whether to call LLM for a richer summary.
   // Triggers: context remaining < 20%, or every 50 user messages as a baseline.
   let llmSummary = null;
-  if (transcriptPath && summary && fs.existsSync(transcriptPath)) {
+  if (transcriptPath && summary && transcriptExists) {
     const contextPct = getContextRemainingPct(transcriptPath);
     const isContextLow = contextPct !== null && contextPct < getContextThreshold();
     const interval = parseInt(process.env.ECC_LLM_SUMMARY_INTERVAL || '50', 10);

tests/hooks/hooks.test.js

@@ -4888,7 +4888,11 @@ async function runTests() {
       const testDir = createTestDir();
       const transcriptPath = path.join(testDir, 'transcript.jsonl');
       // Only user messages — no tool_use entries at all
-      const lines = ['{"type":"user","content":"How does authentication work?"}', '{"type":"assistant","message":{"content":[{"type":"text","text":"It uses JWT"}]}}'];
+      const lines = [
+        '{"type":"user","content":"How does authentication work?"}',
+        '{"type":"assistant","message":{"content":[{"type":"text","text":"It uses JWT"}]}}',
+        '{"type":"user","content":"Explain the token refresh path too"}'
+      ];
       fs.writeFileSync(transcriptPath, lines.join('\n'));
       const stdinJson = JSON.stringify({ transcript_path: transcriptPath });
 
@@ -5262,8 +5266,11 @@ async function runTests() {
     await asyncTest('handles stdin exceeding MAX_STDIN (1MB) gracefully', async () => {
       const testDir = createTestDir();
       const transcriptPath = path.join(testDir, 'transcript.jsonl');
-      // Create a minimal valid transcript so env var fallback works
-      fs.writeFileSync(transcriptPath, JSON.stringify({ type: 'user', content: 'Overflow test' }) + '\n');
+      // Create a substantive valid transcript so env var fallback works
+      fs.writeFileSync(
+        transcriptPath,
+        [JSON.stringify({ type: 'user', content: 'Overflow test' }), JSON.stringify({ type: 'user', content: 'Verify fallback behavior' })].join('\n') + '\n'
+      );
 
       // Create stdin > 1MB: truncated JSON will be invalid → falls back to env var
       const oversizedPayload = '{"transcript_path":"' + 'x'.repeat(1048600) + '"}';
@@ -5880,6 +5887,8 @@ async function runTests() {
       const lines = [
         // Normal user message (string content) — should be included
         '{"type":"user","content":"Real user message"}',
+        // A second valid message keeps this fixture eligible for persistence
+        '{"type":"user","content":"Follow-up user message"}',
         // User message with numeric content — exercises the else: '' branch
         '{"type":"user","content":42}',
         // User message with boolean content — also hits the else branch

tests/hooks/session-end.test.js

@@ -37,6 +37,20 @@ function countOccurrences(haystack, needle) {
   return n;
 }
 
+function runHook(home, transcript, env = {}) {
+  return spawnSync('node', [script], {
+    encoding: 'utf8',
+    input: transcript ? JSON.stringify({ transcript_path: transcript }) : '',
+    env: { ...process.env, HOME: home, USERPROFILE: home, CLAUDE_SESSION_ID: '', ...env },
+    timeout: 10000,
+  });
+}
+
+function sessionFileFor(home, uuid) {
+  const shortId = sanitizeSessionId(uuid.slice(-8).toLowerCase());
+  return path.join(home, '.claude', 'session-data', `${getDateString()}-${shortId}-session.tmp`);
+}
+
 function runTests() {
   console.log('\n=== Testing session-end.js ===\n');
 
@@ -73,7 +87,10 @@ function runTests() {
       const transcript = path.join(home, `${uuid}.jsonl`);
       fs.writeFileSync(
         transcript,
-        JSON.stringify({ type: 'user', message: { role: 'user', content: userText } }) + '\n'
+        [
+          JSON.stringify({ type: 'user', message: { role: 'user', content: userText } }),
+          JSON.stringify({ type: 'tool_use', tool_name: 'Edit', tool_input: { file_path: '/src/release.js' } }),
+        ].join('\n') + '\n'
       );
 
       const res = spawnSync('node', [script], {
@@ -95,6 +112,132 @@ function runTests() {
     }
   }) ? passed++ : failed++);
 
+  (test('writes a session for a multi-message transcript', () => {
+    const home = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-session-end-'));
+    try {
+      const uuid = '11111111-2222-4333-8444-555555555555';
+      const transcript = path.join(home, `${uuid}.jsonl`);
+      fs.writeFileSync(
+        transcript,
+        [
+          JSON.stringify({ type: 'user', content: 'Investigate the failing hook' }),
+          JSON.stringify({ type: 'user', content: 'Add regression coverage' }),
+        ].join('\n') + '\n'
+      );
+
+      const res = runHook(home, transcript);
+      assert.strictEqual(res.status || 0, 0, `hook exited ${res.status}: ${res.stderr}`);
+
+      const sessionFile = sessionFileFor(home, uuid);
+      const out = fs.readFileSync(sessionFile, 'utf8');
+      assert.ok(out.includes(START), 'Should include the generated summary start marker');
+      assert.ok(out.includes(END), 'Should include the generated summary end marker');
+      assert.ok(out.includes('**Last Updated:**'), 'Should include session metadata');
+      assert.ok(out.includes('Add regression coverage'), 'Should include the latest user task');
+    } finally {
+      fs.rmSync(home, { recursive: true, force: true });
+    }
+  }) ? passed++ : failed++);
+
+  (test('writes a session for one user message with tool activity', () => {
+    const home = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-session-end-'));
+    try {
+      const uuid = 'aaaaaaaa-bbbb-4ccc-8ddd-eeeeeeeeeeee';
+      const transcript = path.join(home, `${uuid}.jsonl`);
+      fs.writeFileSync(
+        transcript,
+        [
+          JSON.stringify({ type: 'user', content: 'Fix the configuration' }),
+          JSON.stringify({ type: 'tool_use', tool_name: 'Edit', tool_input: { file_path: '/src/config.js' } }),
+        ].join('\n') + '\n'
+      );
+
+      const res = runHook(home, transcript);
+      assert.strictEqual(res.status || 0, 0, `hook exited ${res.status}: ${res.stderr}`);
+      assert.ok(fs.existsSync(sessionFileFor(home, uuid)), 'Tool activity should make the session eligible');
+    } finally {
+      fs.rmSync(home, { recursive: true, force: true });
+    }
+  }) ? passed++ : failed++);
+
+  (test('skips a one-message prompt with no tool activity', () => {
+    const home = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-session-end-'));
+    try {
+      const uuid = '12345678-1234-4234-8234-123456789abc';
+      const transcript = path.join(home, `${uuid}.jsonl`);
+      fs.writeFileSync(transcript, JSON.stringify({ type: 'user', content: 'Print the current version' }) + '\n');
+
+      const res = runHook(home, transcript);
+      assert.strictEqual(res.status || 0, 0, `hook exited ${res.status}: ${res.stderr}`);
+      assert.ok(!fs.existsSync(sessionFileFor(home, uuid)), 'One-shot prompt should not create a session file');
+      assert.ok(!fs.existsSync(path.join(home, '.claude', 'session-data')), 'Rejected transcript should not create the sessions directory');
+    } finally {
+      fs.rmSync(home, { recursive: true, force: true });
+    }
+  }) ? passed++ : failed++);
+
+  (test('skips a one-message summarizer-style transcript without prompt matching', () => {
+    const home = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-session-end-'));
+    try {
+      const uuid = 'fedcba98-7654-4321-8765-fedcba987654';
+      const transcript = path.join(home, `${uuid}.jsonl`);
+      fs.writeFileSync(
+        transcript,
+        [
+          JSON.stringify({ type: 'user', message: { role: 'user', content: 'Summarize the supplied conversation as concise markdown.' } }),
+          JSON.stringify({ type: 'assistant', message: { role: 'assistant', content: '## Summary\nThe hook behavior was reviewed.' } }),
+        ].join('\n') + '\n'
+      );
+
+      const res = runHook(home, transcript);
+      assert.strictEqual(res.status || 0, 0, `hook exited ${res.status}: ${res.stderr}`);
+      assert.ok(!fs.existsSync(sessionFileFor(home, uuid)), 'Summarizer subprocess should not create a session file');
+    } finally {
+      fs.rmSync(home, { recursive: true, force: true });
+    }
+  }) ? passed++ : failed++);
+
+  (test('does not rewrite an existing session for a rejected transcript', () => {
+    const home = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-session-end-'));
+    try {
+      const uuid = '99999999-8888-4777-8666-555555555555';
+      const transcript = path.join(home, `${uuid}.jsonl`);
+      const sessionFile = sessionFileFor(home, uuid);
+      const original = '# Session: preserved\n**Last Updated:** 09:00\n\n---\n\nUser-authored context\n';
+      const originalTime = new Date('2026-01-02T03:04:05.000Z');
+
+      fs.mkdirSync(path.dirname(sessionFile), { recursive: true });
+      fs.writeFileSync(sessionFile, original);
+      fs.utimesSync(sessionFile, originalTime, originalTime);
+      fs.writeFileSync(transcript, JSON.stringify({ type: 'user', content: 'Answer this one question' }) + '\n');
+
+      const res = runHook(home, transcript);
+      assert.strictEqual(res.status || 0, 0, `hook exited ${res.status}: ${res.stderr}`);
+      assert.strictEqual(fs.readFileSync(sessionFile, 'utf8'), original, 'Rejected transcript should not change existing content');
+      assert.strictEqual(fs.statSync(sessionFile).mtimeMs, originalTime.getTime(), 'Rejected transcript should not advance mtime');
+    } finally {
+      fs.rmSync(home, { recursive: true, force: true });
+    }
+  }) ? passed++ : failed++);
+
+  (test('keeps fallback behavior when transcript metadata is malformed', () => {
+    const home = fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-session-end-'));
+    try {
+      const res = spawnSync('node', [script], {
+        encoding: 'utf8',
+        input: '{not-json',
+        env: { ...process.env, HOME: home, USERPROFILE: home, CLAUDE_SESSION_ID: 'fallback-session-12345678', CLAUDE_TRANSCRIPT_PATH: '' },
+        timeout: 10000,
+      });
+      assert.strictEqual(res.status || 0, 0, `hook exited ${res.status}: ${res.stderr}`);
+
+      const sessionsDir = path.join(home, '.claude', 'session-data');
+      assert.strictEqual(fs.readdirSync(sessionsDir).filter(name => name.endsWith('-session.tmp')).length, 1, 'Fallback should still create the placeholder session');
+    } finally {
+      fs.rmSync(home, { recursive: true, force: true });
+    }
+  }) ? passed++ : failed++);
+
   console.log(`\nResults: Passed: ${passed}, Failed: ${failed}`);
   process.exit(failed > 0 ? 1 : 0);
 }