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fix: keep the live ponytail level across context compaction #1074

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Merged
DietrichGebert merged 2 commits into from
Oct 13, 2026
Merged

fix: keep the live ponytail level across context compaction #1074

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5b5af6c
fix: keep the live ponytail level across context compaction
devohmycode Oct 8, 2026
26049e9
Merge main into fix/keep-mode-on-compact (keep #1082 map in a child p…
Oct 13, 2026
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286 changes: 157 additions & 129 deletions hooks/ponytail-activate.js
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Original file line number Diff line number Diff line change
Expand Up @@ -20,153 +20,181 @@ const {
isCodex,
isCopilot,
isCursor,
readMode,
setMode,
writeHookOutput,
} = require('./ponytail-runtime');

const claudeDir = getClaudeDir();
const settingsPath = path.join(claudeDir, 'settings.json');

const mode = getDefaultMode();

// "off" mode — skip activation entirely, don't write flag or emit rules
if (mode === 'off') {
clearMode();
process.exit(0);
}
function activate(mode) {
// "off" mode — skip activation entirely, don't write flag or emit rules
if (mode === 'off') {
clearMode();
process.exit(0);
}

// Cursor with the always-on rule in the workspace: the rule already carries the
// ruleset and would contradict any other level, so leave the flag alone and
// hand the model a one-line notice instead of a second copy (#817).
if (isCursor) {
const rule = cursorRulePath();
if (rule) {
try {
writeHookOutput('SessionStart', mode, cursorRuleNotice(rule));
} catch (e) {
// Silent fail — stdout closed/EPIPE at hook exit must not surface as a hook failure
// Cursor with the always-on rule in the workspace: the rule already carries the
// ruleset and would contradict any other level, so leave the flag alone and
// hand the model a one-line notice instead of a second copy (#817).
if (isCursor) {
const rule = cursorRulePath();
if (rule) {
try {
writeHookOutput('SessionStart', mode, cursorRuleNotice(rule));
} catch (e) {
// Silent fail — stdout closed/EPIPE at hook exit must not surface as a hook failure
}
process.exit(0);
}
process.exit(0);
}
}

// 1. Write flag file
try {
setMode(mode);
} catch (e) {
// Silent fail -- flag is best-effort, don't block the hook
}
// 1. Write flag file
try {
setMode(mode);
} catch (e) {
// Silent fail -- flag is best-effort, don't block the hook
}

// 2. Emit the ponytail ruleset, filtered to the active intensity level.
let output = getPonytailInstructions(mode);

// 2b. Codebase map: what already exists, so "reuse first" costs no search. Fail open: a map
// that cannot be built must never block or slow the session start.
if (mode !== 'review' && process.env.PONYTAIL_MAP !== '0') try {
const map = execFileSync(process.execPath, [path.join(__dirname, 'ponytail-map.js')], {
encoding: 'utf8', timeout: 1000, maxBuffer: 64 * 1024, stdio: ['ignore', 'pipe', 'ignore'],
}).trimEnd();
if (map) output += '\n\n' + map;
} catch (e) { /* no map */ }

// 2. Emit the ponytail ruleset, filtered to the active intensity level.
let output = getPonytailInstructions(mode);

// 2b. Codebase map: what already exists, so "reuse first" costs no search. Fail open: a map
// that cannot be built must never block or slow the session start.
if (mode !== 'review' && process.env.PONYTAIL_MAP !== '0') try {
const map = execFileSync(process.execPath, [path.join(__dirname, 'ponytail-map.js')], {
encoding: 'utf8', timeout: 1000, maxBuffer: 64 * 1024, stdio: ['ignore', 'pipe', 'ignore'],
}).trimEnd();
if (map) output += '\n\n' + map;
} catch (e) { /* no map */ }

// 3. Detect missing statusline config — nudge Claude to help set it up
if (!isCodex && !isCopilot && !isCursor && !isCodeBuddy) try {
const isWindows = process.platform === 'win32';
let statusCommand = null;
if (fs.existsSync(settingsPath)) {
// Strip UTF-8 BOM some editors prepend on Windows (breaks JSON.parse)
const raw = fs.readFileSync(settingsPath, 'utf8').replace(/^\uFEFF/, '');
const settings = JSON.parse(raw);
if (settings.statusLine) {
statusCommand = String(settings.statusLine.command || '');
// 3. Detect missing statusline config — nudge Claude to help set it up
if (!isCodex && !isCopilot && !isCursor && !isCodeBuddy) try {
const isWindows = process.platform === 'win32';
let statusCommand = null;
if (fs.existsSync(settingsPath)) {
// Strip UTF-8 BOM some editors prepend on Windows (breaks JSON.parse)
const raw = fs.readFileSync(settingsPath, 'utf8').replace(/^\uFEFF/, '');
const settings = JSON.parse(raw);
if (settings.statusLine) {
statusCommand = String(settings.statusLine.command || '');
}
}
}

// A statusLine already set up before #1032 can still run a script from a
// plugin version that has since been deleted. Only absolute paths are checked,
// so ~ or $HOME forms are never mistaken for missing files.
const ref = statusCommand &&
statusCommand.match(/"([^"]*ponytail-statusline\.(?:sh|ps1))"|(\S*ponytail-statusline\.(?:sh|ps1))/);
const refPath = ref ? (ref[1] || ref[2]) : null;
// isShellSafe keeps quotes, newlines and shell metacharacters from
// settings.json out of the model context.
// On Windows only drive-letter or UNC paths count: a Git Bash path such as
// /c/Users/... is absolute to Node but does not resolve, so it would be
// flagged as broken while it works.
const checkable = refPath && isShellSafe(refPath) && path.isAbsolute(refPath) &&
(!isWindows || /^([A-Za-z]:[\\/]|\\\\)/.test(refPath));
const stalePath = checkable && !fs.existsSync(refPath) ? refPath : null;

// The plugin root is a versioned cache dir (.../ponytail/4.12.0/) that Claude
// Code deletes on update, so a statusLine pointing into it goes blank after the
// next update (#1032). Point it at a copy in the config dir instead. A statusLine
// that already runs ponytail keeps its script type, so its copy stays fresh.
const usePs1 = refPath ? refPath.endsWith('.ps1') : isWindows;
const scriptName = usePs1 ? 'ponytail-statusline.ps1' : 'ponytail-statusline.sh';
const scriptPath = path.join(claudeDir, scriptName);

// Nudge at most once — the flag file marks that the user has already seen
// (and implicitly declined) the statusline setup offer. Repeating it every
// session start turns a helpful hint into a nag. A broken path is nudged once
// per path: the flag records it.
const nudgeFlagPath = path.join(claudeDir, '.ponytail-statusline-nudged');
let nudged = null;
try { nudged = fs.readFileSync(nudgeFlagPath, 'utf8'); } catch (e) { /* not nudged yet */ }
const nudge = stalePath ? nudged !== stalePath : statusCommand === null && nudged === null;

// Refresh the copy every session so script fixes ship with plugin updates.
// Copy to a new temp file, then rename: the rename replaces a symlink at
// scriptPath instead of writing through it, and a concurrent session never
// runs a half-written script.
if (nudge || fs.existsSync(scriptPath)) {
const tmpPath = scriptPath + '.' + process.pid + '.tmp';
try {
fs.copyFileSync(path.join(__dirname, scriptName), tmpPath, fs.constants.COPYFILE_EXCL);
fs.chmodSync(tmpPath, 0o644);
fs.renameSync(tmpPath, scriptPath);
} finally {
try { fs.unlinkSync(tmpPath); } catch (e) { /* renamed */ }
// A statusLine already set up before #1032 can still run a script from a
// plugin version that has since been deleted. Only absolute paths are checked,
// so ~ or $HOME forms are never mistaken for missing files.
const ref = statusCommand &&
statusCommand.match(/"([^"]*ponytail-statusline\.(?:sh|ps1))"|(\S*ponytail-statusline\.(?:sh|ps1))/);
const refPath = ref ? (ref[1] || ref[2]) : null;
// isShellSafe keeps quotes, newlines and shell metacharacters from
// settings.json out of the model context.
// On Windows only drive-letter or UNC paths count: a Git Bash path such as
// /c/Users/... is absolute to Node but does not resolve, so it would be
// flagged as broken while it works.
const checkable = refPath && isShellSafe(refPath) && path.isAbsolute(refPath) &&
(!isWindows || /^([A-Za-z]:[\\/]|\\\\)/.test(refPath));
const stalePath = checkable && !fs.existsSync(refPath) ? refPath : null;

// The plugin root is a versioned cache dir (.../ponytail/4.12.0/) that Claude
// Code deletes on update, so a statusLine pointing into it goes blank after the
// next update (#1032). Point it at a copy in the config dir instead. A statusLine
// that already runs ponytail keeps its script type, so its copy stays fresh.
const usePs1 = refPath ? refPath.endsWith('.ps1') : isWindows;
const scriptName = usePs1 ? 'ponytail-statusline.ps1' : 'ponytail-statusline.sh';
const scriptPath = path.join(claudeDir, scriptName);

// Nudge at most once — the flag file marks that the user has already seen
// (and implicitly declined) the statusline setup offer. Repeating it every
// session start turns a helpful hint into a nag. A broken path is nudged once
// per path: the flag records it.
const nudgeFlagPath = path.join(claudeDir, '.ponytail-statusline-nudged');
let nudged = null;
try { nudged = fs.readFileSync(nudgeFlagPath, 'utf8'); } catch (e) { /* not nudged yet */ }
const nudge = stalePath ? nudged !== stalePath : statusCommand === null && nudged === null;

// Refresh the copy every session so script fixes ship with plugin updates.
// Copy to a new temp file, then rename: the rename replaces a symlink at
// scriptPath instead of writing through it, and a concurrent session never
// runs a half-written script.
if (nudge || fs.existsSync(scriptPath)) {
const tmpPath = scriptPath + '.' + process.pid + '.tmp';
try {
fs.copyFileSync(path.join(__dirname, scriptName), tmpPath, fs.constants.COPYFILE_EXCL);
fs.chmodSync(tmpPath, 0o644);
fs.renameSync(tmpPath, scriptPath);
} finally {
try { fs.unlinkSync(tmpPath); } catch (e) { /* renamed */ }
}
}
}

if (nudge) {
try { fs.writeFileSync(nudgeFlagPath, stalePath || ''); } catch (e) { /* best-effort */ }
if (stalePath) {
output += "\n\n" +
"STATUSLINE BROKEN: The statusLine in " + settingsPath + " runs " + stalePath +
", which no longer exists (the ponytail plugin was updated and its old version removed), " +
"so the ponytail badge is blank. Replace that path with " + scriptPath + ", which survives updates, " +
"quoting it for your shell. Keep the rest of the command. " +
"Proactively offer to fix this for the user on first interaction.";
} else if (isShellSafe(scriptPath)) {
const command = isWindows
? `powershell -ExecutionPolicy Bypass -File "${scriptPath}"`
: `bash "${scriptPath}"`;
const statusLineSnippet =
'"statusLine": { "type": "command", "command": ' + JSON.stringify(command) + ' }';
output += "\n\n" +
"STATUSLINE SETUP NEEDED: The ponytail plugin includes a statusline badge showing active mode " +
"(e.g. [PONYTAIL], [PONYTAIL:ULTRA]). It is not configured yet. " +
"To enable, add this to " + settingsPath + ": " +
statusLineSnippet + " " +
"Proactively offer to set this up for the user on first interaction.";
} else {
// ponytail: config dir path has shell metacharacters; don't embed it in a
// command snippet; have the agent wire it up by hand instead.
output += "\n\n" +
"STATUSLINE SETUP NEEDED: The ponytail plugin includes a statusline badge showing active mode. " +
"Its path contains characters unsafe to embed in a shell command, so configure it manually: " +
"add a statusLine command of type \"command\" that runs " + scriptName +
" from " + claudeDir + " to " + settingsPath + ", quoting/escaping the path for your shell. " +
"Proactively offer to set this up for the user on first interaction.";
if (nudge) {
try { fs.writeFileSync(nudgeFlagPath, stalePath || ''); } catch (e) { /* best-effort */ }
if (stalePath) {
output += "\n\n" +
"STATUSLINE BROKEN: The statusLine in " + settingsPath + " runs " + stalePath +
", which no longer exists (the ponytail plugin was updated and its old version removed), " +
"so the ponytail badge is blank. Replace that path with " + scriptPath + ", which survives updates, " +
"quoting it for your shell. Keep the rest of the command. " +
"Proactively offer to fix this for the user on first interaction.";
} else if (isShellSafe(scriptPath)) {
const command = isWindows
? `powershell -ExecutionPolicy Bypass -File "${scriptPath}"`
: `bash "${scriptPath}"`;
const statusLineSnippet =
'"statusLine": { "type": "command", "command": ' + JSON.stringify(command) + ' }';
output += "\n\n" +
"STATUSLINE SETUP NEEDED: The ponytail plugin includes a statusline badge showing active mode " +
"(e.g. [PONYTAIL], [PONYTAIL:ULTRA]). It is not configured yet. " +
"To enable, add this to " + settingsPath + ": " +
statusLineSnippet + " " +
"Proactively offer to set this up for the user on first interaction.";
} else {
// ponytail: config dir path has shell metacharacters; don't embed it in a
// command snippet; have the agent wire it up by hand instead.
output += "\n\n" +
"STATUSLINE SETUP NEEDED: The ponytail plugin includes a statusline badge showing active mode. " +
"Its path contains characters unsafe to embed in a shell command, so configure it manually: " +
"add a statusLine command of type \"command\" that runs " + scriptName +
" from " + claudeDir + " to " + settingsPath + ", quoting/escaping the path for your shell. " +
"Proactively offer to set this up for the user on first interaction.";
}
}
} catch (e) {
// Silent fail — don't block session start over statusline detection
}

try {
writeHookOutput('SessionStart', mode, output);
} catch (e) {
// Silent fail — stdout closed/EPIPE at hook exit must not surface as a hook failure
}
} catch (e) {
// Silent fail — don't block session start over statusline detection
}

try {
writeHookOutput('SessionStart', mode, output);
} catch (e) {
// Silent fail — stdout closed/EPIPE at hook exit must not surface as a hook failure
// Compaction re-runs SessionStart inside the same conversation, so it keeps the
// live level (or stays off after "stop ponytail") instead of resetting to the
// default. Claude Code and Codex pass the trigger as `source` on stdin; reading
// it there keeps the hook entry, and the trust Codex gave it, unchanged.
let input = '';
let done = false;

function finish() {
if (done) return;
done = true;
let source = '';
try {
// Strip UTF-8 BOM some shells prepend when piping (breaks JSON.parse)
source = JSON.parse(input.replace(/^\uFEFF/, '')).source;
} catch (e) {
// No payload, or an unparseable one: treat it as a fresh session
}
activate(source === 'compact' ? (readMode() || 'off') : getDefaultMode());
}

process.stdin.on('data', chunk => { input += chunk; });
// Never hang the session start (#443, #790): like the mode tracker, recover on a
// stdin error or after a short ref'd fallback, and start at the default level.
process.stdin.on('end', () => { finish(); process.exit(0); });
process.stdin.on('error', () => { finish(); process.exit(0); });
setTimeout(() => { finish(); process.exit(0); }, 1000);
39 changes: 23 additions & 16 deletions tests/hooks-windows.test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -107,23 +107,30 @@ test('every hook command points at a script that ships in hooks/', () => {
// Issue #443: on Windows the UserPromptSubmit hook runs inside a PowerShell
// `if {}` wrapper that can swallow the piped prompt JSON, so stdin 'end' never
// fires. The hook must never wait on stdin forever — that freezes the whole
// session. It has to self-exit even when stdin stays open and empty.
test('ponytail-mode-tracker self-exits when stdin never closes (no freeze)', async () => {
const hook = path.join(root, 'hooks', 'ponytail-mode-tracker.js');
// stdin is a pipe we never write to or end, reproducing the deadlock.
const child = spawn(process.execPath, [hook], { stdio: ['pipe', 'ignore', 'ignore'] });

const code = await new Promise((resolve, reject) => {
const guard = setTimeout(() => {
child.kill('SIGKILL');
reject(new Error('hook hung on open stdin — it would freeze the session'));
}, 3000);
child.on('exit', (c) => { clearTimeout(guard); resolve(c); });
child.on('error', reject);
// session. It has to self-exit even when stdin stays open and empty. The
// activate hook reads the SessionStart source from stdin too.
for (const script of ['ponytail-mode-tracker.js', 'ponytail-activate.js']) {
test(`${script} self-exits when stdin never closes (no freeze)`, async () => {
const hook = path.join(root, 'hooks', script);
// A throwaway home: the activate fallback writes the flag and the statusline copy.
const home = fs.mkdtempSync(path.join(os.tmpdir(), 'ponytail-stdin-'));
const env = { ...process.env, HOME: home, USERPROFILE: home, CLAUDE_CONFIG_DIR: path.join(home, '.claude'), PONYTAIL_MAP: '0' };
// stdin is a pipe we never write to or end, reproducing the deadlock.
const child = spawn(process.execPath, [hook], { env, stdio: ['pipe', 'ignore', 'ignore'] });

const code = await new Promise((resolve, reject) => {
const guard = setTimeout(() => {
child.kill('SIGKILL');
reject(new Error('hook hung on open stdin — it would freeze the session'));
}, 3000);
child.on('exit', (c) => { clearTimeout(guard); resolve(c); });
child.on('error', reject);
});
fs.rmSync(home, { recursive: true, force: true });

assert.equal(code, 0, 'hook must exit cleanly when stdin never closes');
});

assert.equal(code, 0, 'hook must exit cleanly when stdin never closes');
});
}

test('Claude and Codex manifests point at the shared host-specific hook config', () => {
for (const rel of HOST_PLUGIN_MANIFESTS) {
Expand Down
24 changes: 24 additions & 0 deletions tests/hooks.test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -935,4 +935,28 @@ assert.equal(
assert.equal(fs.readFileSync(bareFlag, 'utf8'), 'full', 'an off default still switches on at full');
}

// Compaction re-runs SessionStart inside the same conversation: it must keep the
// live level, and keep ponytail off after "stop ponytail", not reset to the default.
{
const compactHome = path.join(temp, 'compact-home');
const compactFlag = path.join(compactHome, '.claude', '.ponytail-active');
const compactEnv = { HOME: compactHome, USERPROFILE: compactHome };
const start = (source) => run('ponytail-activate.js', compactEnv, JSON.stringify({ source }));
const compact = () => start('compact');

start('startup');
run('ponytail-mode-tracker.js', compactEnv, JSON.stringify({ prompt: '/ponytail ultra' }));
assert.match(compact().stdout, /PONYTAIL MODE ACTIVE — level: ultra/);
assert.equal(fs.readFileSync(compactFlag, 'utf8'), 'ultra', 'compaction must keep the live level');

run('ponytail-mode-tracker.js', compactEnv, JSON.stringify({ prompt: 'stop ponytail' }));
assert.equal(compact().stdout, '', 'compaction must not switch a stopped session back on');
assert.equal(fs.existsSync(compactFlag), false);

// Every other source still starts at the default level.
for (const source of ['startup', 'resume', 'clear']) {
assert.match(start(source).stdout, /PONYTAIL MODE ACTIVE — level: full/, `${source} must start at the default level`);
}
}

console.log('hook compatibility checks passed');
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