From 7b9dd97689db400f2408ed50b04857d7d73d83e5 Mon Sep 17 00:00:00 2001
From: Agando <roduccomm@gmail.com>
Date: Tue, 29 Sep 2026 15:56:27 +0200
Subject: newOS4 v4.6.15: reentrant print-capture stack, AI tail -f block,
 read-only sed in safeRead, security test harness (21 checks)

---
 main.html                          |   6 +-
 modules/core/core-bundle.js        |  62 ++++++++----
 modules/core/module-aiassist.js    |  33 +++----
 modules/core/module-fs.js          |   4 +
 modules/core/terminal.js           |  25 ++++-
 modules/ext/critical-ext-bundle.js |  20 ++--
 modules/ext/shell.js               |  20 ++--
 scripts/test-security.mjs          | 194 +++++++++++++++++++++++++++++++++++++
 8 files changed, 303 insertions(+), 61 deletions(-)
 create mode 100644 scripts/test-security.mjs

diff --git a/main.html b/main.html
index 73a64f1..4b79775 100644
--- a/main.html
+++ b/main.html
@@ -1345,13 +1345,13 @@
     </script>
 
     <!-- v4.5.63: A2A scratchpad fixes + agent-register arg fix -->
-<script src="modules/core/core-bundle.js?v=v4.6.14"></script>
+<script src="modules/core/core-bundle.js?v=v4.6.15"></script>
 
     <!-- Async dependency-ordered module loader now only initializes terminal and loads optional ext modules -->
-<script src="modules/core/module-loader.js?v=v4.6.14"></script>
+<script src="modules/core/module-loader.js?v=v4.6.15"></script>
 
     <!-- Critical ext bundle loads AFTER webx11 exists so registerModule calls work -->
-<script src="modules/ext/critical-ext-bundle.js?v=v4.6.14"></script>
+<script src="modules/ext/critical-ext-bundle.js?v=v4.6.15"></script>
 
 <script>
 // ═══ ONE TRUE VERSION SOURCE ═══
diff --git a/modules/core/core-bundle.js b/modules/core/core-bundle.js
index c7a91dc..6127f36 100644
--- a/modules/core/core-bundle.js
+++ b/modules/core/core-bundle.js
@@ -2726,6 +2726,9 @@ Only output XML function calls for tool tasks. If no tool is needed, answer norm
                 this._pipeInput = null;
                 this._pipeBufferSize = 5000;
                 this._activeFollow = null;
+                // Print-capture stack: [{output: ''}] — see print() head. LIFO order:
+                // nested/parallel captures each get their own buffer.
+                this._printCaptureStack = [];
                 this._historyBuffer = [];
                 this._historyMaxLines = 50;
                 this._historySavePending = false;
@@ -2783,6 +2786,15 @@ Only output XML function calls for tool tasks. If no tool is needed, answer norm
             _invalidateCommandCache() {
                 if (this.security) this.security.invalidateCommandCache();
             }
+            _pushPrintCapture(onChunk) {
+                // onChunk(buffer) called at pop with the full captured text
+                if (!this._printCaptureStack) this._printCaptureStack = [];
+                this._printCaptureStack.push({ output: '', onChunk });
+            }
+            _popPrintCapture() {
+                const cap = this._printCaptureStack && this._printCaptureStack.pop();
+                if (cap && cap.onChunk) cap.onChunk(cap.output);
+            }
             stopFollow(msg) {
                 if (!this._activeFollow) return false;
                 clearInterval(this._activeFollow.interval);
@@ -2968,6 +2980,14 @@ Only output XML function calls for tool tasks. If no tool is needed, answer norm
                 label.textContent = prefix + (path === '/' ? '$' : path + ' $');
             }
             print(text, type = '') {
+                // Print-capture stack: while active, output goes to the innermost capture
+                // buffer instead of the DOM. Reentrant — parallel/nested captures each
+                // collect their own output (race-safe, replaces monkey-patched print).
+                if (this._printCaptureStack && this._printCaptureStack.length > 0) {
+                    const cap = this._printCaptureStack[this._printCaptureStack.length - 1];
+                    cap.output += text + '\n';
+                    return;
+                }
                 if (['error','warning','success','info','text-muted'].includes(type) && !this._showSystemMessages && !type.startsWith('command')) {
                     // Still log to history buffer so it can be shown again when toggled on,
                     // but don't create DOM nodes while system messages are hidden.
@@ -3958,13 +3978,12 @@ Only output XML function calls for tool tasks. If no tool is needed, answer norm
                 this._pipeInput = null;
             }
             async capturePipeOutput(cmd, args) {
-                const originalPrint = this.print.bind(this);
                 let output = '';
-                this.print = (text, type) => { output += text + '\n'; };
+                this._pushPrintCapture(buf => { output += buf; });
                 try {
                     await this.dispatchCommand(cmd, args);
                 } finally {
-                    this.print = originalPrint;
+                    this._popPrintCapture();
                 }
                 const trimmed = output.trim();
                 if (trimmed.length > this._pipeBufferSize) {
@@ -6432,6 +6451,10 @@ class FileSystemModule {
             if (c === null || c === undefined) return this.terminal.print('tail: ' + file + ': No such file', 'error');
             this.terminal.print(c.split('\n').slice(-n).join('\n'));
             if (!follow) return;
+            // AI tool calls cannot press Ctrl+C — auto-downgrade to a bounded read instead of a live timer
+            if (this.terminal.security && this.terminal.security._aiToolDepth > 0) {
+                return this.terminal.print('tail: follow mode (-f) is interactive-only; showing last lines instead (use tail -n ' + Math.max(n, 50) + ' for more)', 'warning');
+            }
             // stop any previous follow before starting a new one
             if (this.terminal._activeFollow && this.terminal._activeFollow.interval) clearInterval(this.terminal._activeFollow.interval);
             this.terminal._activeFollow = null;
@@ -8937,24 +8960,22 @@ buildSystemPrompt() {
             }
             // ─── Self-Improvement Helpers ───
             async _captureCommandOutput(cmd) {
-                const originalPrint = this.terminal.print.bind(this.terminal);
                 let output = '';
-                this.terminal.print = (text, type) => { output += text + '\n'; };
                 // Loop guard: AI-initiated commands must not route back to AI on unknown command
                 this.terminal.security._aiToolDepth++;
+                this.terminal._pushPrintCapture(buf => { output += buf; });
                 try { await this.terminal.security.checkAndRun(cmd); }
-                finally { this.terminal.security._aiToolDepth--; this.terminal.print = originalPrint; }
+                finally { this.terminal._popPrintCapture(); this.terminal.security._aiToolDepth--; }
                 return output.trim();
             }
             async _captureShellCommand(cmd) {
                 // Routes through executeCommand (shell parser) for >, |, &&, export, etc.
-                const originalPrint = this.terminal.print.bind(this.terminal);
                 let output = '';
-                this.terminal.print = (text, type) => { output += text + '\n'; };
                 // Loop guard: AI-initiated commands must not route back to AI on unknown command
                 this.terminal.security._aiToolDepth++;
+                this.terminal._pushPrintCapture(buf => { output += buf; });
                 try { await this.terminal.executeCommand(cmd); }
-                finally { this.terminal.security._aiToolDepth--; this.terminal.print = originalPrint; }
+                finally { this.terminal._popPrintCapture(); this.terminal.security._aiToolDepth--; }
                 return output.trim();
             }
             async _captureConsoleErrors(durationMs) {
@@ -10003,11 +10024,10 @@ buildSystemPrompt() {
                 this._snapshotShadowVFS();
                 const cmdName = cmd.split(' ')[0].toLowerCase();
                 const cmdArgs = cmd.split(' ').slice(1);
-                const originalPrint = this.terminal.print.bind(this.terminal);
                 let output = '';
-                this.terminal.print = (text, type) => { output += text + '\n'; };
+                this.terminal._pushPrintCapture(buf => { output += buf; });
                 this.terminal.dispatchCommand(cmdName, cmdArgs).then(() => {
-                    this.terminal.print = originalPrint;
+                    this.terminal._popPrintCapture();
                     const diff = this._diffShadowVFS(false);
                     if (!diff || diff.length === 0) {
                         this.terminal.print('📦 Shadow: No filesystem changes detected.', 'success');
@@ -10024,7 +10044,7 @@ buildSystemPrompt() {
                         this.terminal.print('🔒 VFS modified — type "shadow-commit" to accept or "shadow-rollback" to undo.', 'warning');
                     }
                 }).catch(e => {
-                    this.terminal.print = originalPrint;
+                    this.terminal._popPrintCapture();
                     this.terminal.print('⚠️ Shadow command error: ' + e.message, 'error');
                 });
             }
@@ -10052,8 +10072,11 @@ buildSystemPrompt() {
                 if (name === 'run_command') {
                     const cmdStr = typeof args === 'object' ? (args?.command || '') : String(args);
                     const cmd = cmdStr.split(' ')[0].toLowerCase();
+                    // sed: read-only UNLESS -i (in-place write) or it starts a live tail -f timer
+                    if (cmd === 'sed' && /(^|\s)-i(\s|$)/.test(cmdStr)) return true;
+                    if (cmd === 'tail' && /(^|\s)-f\b|(^|\s)--follow\b/.test(cmdStr)) return false; // tail -f self-downgrades for AI (module-fs guard)
                     const safeRead = new Set(['ls','cat','pwd','echo','date','env','whoami','which','hostname',
-                        'cal','tree','find','grep','head','tail','sort','wc','du','diff','basename','dirname',
+                        'cal','tree','find','grep','head','tail','sed','sort','wc','du','diff','basename','dirname',
                         'yes','seq','cut','uniq','expand','printf','base64','help','clear','set','export',
                         'unalias','history','ll','h','mem','status','df','free','top','ps','health-check',
                         'system-health','modules','listmods','modules-list','get-help-info','alias',
@@ -10239,10 +10262,9 @@ buildSystemPrompt() {
                             if (!kw) return JSON.stringify({ error: 'No keyword' });
                             const mod = this.terminal.moduleManager.modules['WpmModule'];
                             if (mod) {
-                                const originalPrint = this.terminal.print.bind(this.terminal);
                                 let output = '';
-                                this.terminal.print = (text, type) => { output += text + '\n'; };
-                                try { await mod.search(kw); } finally { this.terminal.print = originalPrint; }
+                                this.terminal._pushPrintCapture(buf => { output += buf; });
+                                try { await mod.search(kw); } finally { this.terminal._popPrintCapture(); }
                                 return output.trim() || 'Search completed';
                             }
                             return JSON.stringify({ error: 'WPM module not available' });
@@ -10252,13 +10274,13 @@ buildSystemPrompt() {
                             if (!cmd) return JSON.stringify({ error: 'No command provided' });
                             // 📸 Shadow VFS auto-snapshot before run_command
                             this._snapshotShadowVFS();
-                            const originalPrint = this.terminal.print.bind(this.terminal);
                             let output = '';
-                            this.terminal.print = (text, type) => { output += text + '\n'; };
                             // Loop guard (depth counter — race-safe under Promise.all tool fan-out):
                             // unknown commands return an error instead of routing back to AI
                             this.terminal.security._aiToolDepth++;
-                            try { await this.terminal.security.checkAndRun(cmd); } finally { this.terminal.security._aiToolDepth--; this.terminal.print = originalPrint; }
+                            this.terminal._pushPrintCapture(buf => { output += buf; });
+                            try { await this.terminal.security.checkAndRun(cmd); }
+                            finally { this.terminal._popPrintCapture(); this.terminal.security._aiToolDepth--; }
                             // Parse per-call captured output (race-free) — not shared security state
                             const nfMatch = output.match(/Command not found: ([^\s.]+)(?:\. Did you mean: ([^\s.?]+)\?)?/);
                             if (nfMatch) {
diff --git a/modules/core/module-aiassist.js b/modules/core/module-aiassist.js
index 3d04df7..9c090ce 100644
--- a/modules/core/module-aiassist.js
+++ b/modules/core/module-aiassist.js
@@ -945,24 +945,22 @@ buildSystemPrompt() {
             }
             // ─── Self-Improvement Helpers ───
             async _captureCommandOutput(cmd) {
-                const originalPrint = this.terminal.print.bind(this.terminal);
                 let output = '';
-                this.terminal.print = (text, type) => { output += text + '\n'; };
                 // Loop guard: AI-initiated commands must not route back to AI on unknown command
                 this.terminal.security._aiToolDepth++;
+                this.terminal._pushPrintCapture(buf => { output += buf; });
                 try { await this.terminal.security.checkAndRun(cmd); }
-                finally { this.terminal.security._aiToolDepth--; this.terminal.print = originalPrint; }
+                finally { this.terminal._popPrintCapture(); this.terminal.security._aiToolDepth--; }
                 return output.trim();
             }
             async _captureShellCommand(cmd) {
                 // Routes through executeCommand (shell parser) for >, |, &&, export, etc.
-                const originalPrint = this.terminal.print.bind(this.terminal);
                 let output = '';
-                this.terminal.print = (text, type) => { output += text + '\n'; };
                 // Loop guard: AI-initiated commands must not route back to AI on unknown command
                 this.terminal.security._aiToolDepth++;
+                this.terminal._pushPrintCapture(buf => { output += buf; });
                 try { await this.terminal.executeCommand(cmd); }
-                finally { this.terminal.security._aiToolDepth--; this.terminal.print = originalPrint; }
+                finally { this.terminal._popPrintCapture(); this.terminal.security._aiToolDepth--; }
                 return output.trim();
             }
             async _captureConsoleErrors(durationMs) {
@@ -2011,11 +2009,10 @@ buildSystemPrompt() {
                 this._snapshotShadowVFS();
                 const cmdName = cmd.split(' ')[0].toLowerCase();
                 const cmdArgs = cmd.split(' ').slice(1);
-                const originalPrint = this.terminal.print.bind(this.terminal);
                 let output = '';
-                this.terminal.print = (text, type) => { output += text + '\n'; };
+                this.terminal._pushPrintCapture(buf => { output += buf; });
                 this.terminal.dispatchCommand(cmdName, cmdArgs).then(() => {
-                    this.terminal.print = originalPrint;
+                    this.terminal._popPrintCapture();
                     const diff = this._diffShadowVFS(false);
                     if (!diff || diff.length === 0) {
                         this.terminal.print('📦 Shadow: No filesystem changes detected.', 'success');
@@ -2032,7 +2029,7 @@ buildSystemPrompt() {
                         this.terminal.print('🔒 VFS modified — type "shadow-commit" to accept or "shadow-rollback" to undo.', 'warning');
                     }
                 }).catch(e => {
-                    this.terminal.print = originalPrint;
+                    this.terminal._popPrintCapture();
                     this.terminal.print('⚠️ Shadow command error: ' + e.message, 'error');
                 });
             }
@@ -2060,8 +2057,11 @@ buildSystemPrompt() {
                 if (name === 'run_command') {
                     const cmdStr = typeof args === 'object' ? (args?.command || '') : String(args);
                     const cmd = cmdStr.split(' ')[0].toLowerCase();
+                    // sed: read-only UNLESS -i (in-place write) or it starts a live tail -f timer
+                    if (cmd === 'sed' && /(^|\s)-i(\s|$)/.test(cmdStr)) return true;
+                    if (cmd === 'tail' && /(^|\s)-f\b|(^|\s)--follow\b/.test(cmdStr)) return false; // tail -f self-downgrades for AI (module-fs guard)
                     const safeRead = new Set(['ls','cat','pwd','echo','date','env','whoami','which','hostname',
-                        'cal','tree','find','grep','head','tail','sort','wc','du','diff','basename','dirname',
+                        'cal','tree','find','grep','head','tail','sed','sort','wc','du','diff','basename','dirname',
                         'yes','seq','cut','uniq','expand','printf','base64','help','clear','set','export',
                         'unalias','history','ll','h','mem','status','df','free','top','ps','health-check',
                         'system-health','modules','listmods','modules-list','get-help-info','alias',
@@ -2247,10 +2247,9 @@ buildSystemPrompt() {
                             if (!kw) return JSON.stringify({ error: 'No keyword' });
                             const mod = this.terminal.moduleManager.modules['WpmModule'];
                             if (mod) {
-                                const originalPrint = this.terminal.print.bind(this.terminal);
                                 let output = '';
-                                this.terminal.print = (text, type) => { output += text + '\n'; };
-                                try { await mod.search(kw); } finally { this.terminal.print = originalPrint; }
+                                this.terminal._pushPrintCapture(buf => { output += buf; });
+                                try { await mod.search(kw); } finally { this.terminal._popPrintCapture(); }
                                 return output.trim() || 'Search completed';
                             }
                             return JSON.stringify({ error: 'WPM module not available' });
@@ -2260,13 +2259,13 @@ buildSystemPrompt() {
                             if (!cmd) return JSON.stringify({ error: 'No command provided' });
                             // 📸 Shadow VFS auto-snapshot before run_command
                             this._snapshotShadowVFS();
-                            const originalPrint = this.terminal.print.bind(this.terminal);
                             let output = '';
-                            this.terminal.print = (text, type) => { output += text + '\n'; };
                             // Loop guard (depth counter — race-safe under Promise.all tool fan-out):
                             // unknown commands return an error instead of routing back to AI
                             this.terminal.security._aiToolDepth++;
-                            try { await this.terminal.security.checkAndRun(cmd); } finally { this.terminal.security._aiToolDepth--; this.terminal.print = originalPrint; }
+                            this.terminal._pushPrintCapture(buf => { output += buf; });
+                            try { await this.terminal.security.checkAndRun(cmd); }
+                            finally { this.terminal._popPrintCapture(); this.terminal.security._aiToolDepth--; }
                             // Parse per-call captured output (race-free) — not shared security state
                             const nfMatch = output.match(/Command not found: ([^\s.]+)(?:\. Did you mean: ([^\s.?]+)\?)?/);
                             if (nfMatch) {
diff --git a/modules/core/module-fs.js b/modules/core/module-fs.js
index 112302b..d94feb8 100644
--- a/modules/core/module-fs.js
+++ b/modules/core/module-fs.js
@@ -256,6 +256,10 @@ class FileSystemModule {
             if (c === null || c === undefined) return this.terminal.print('tail: ' + file + ': No such file', 'error');
             this.terminal.print(c.split('\n').slice(-n).join('\n'));
             if (!follow) return;
+            // AI tool calls cannot press Ctrl+C — auto-downgrade to a bounded read instead of a live timer
+            if (this.terminal.security && this.terminal.security._aiToolDepth > 0) {
+                return this.terminal.print('tail: follow mode (-f) is interactive-only; showing last lines instead (use tail -n ' + Math.max(n, 50) + ' for more)', 'warning');
+            }
             // stop any previous follow before starting a new one
             if (this.terminal._activeFollow && this.terminal._activeFollow.interval) clearInterval(this.terminal._activeFollow.interval);
             this.terminal._activeFollow = null;
diff --git a/modules/core/terminal.js b/modules/core/terminal.js
index 3b28b52..123c224 100644
--- a/modules/core/terminal.js
+++ b/modules/core/terminal.js
@@ -300,6 +300,9 @@
                 this._pipeInput = null;
                 this._pipeBufferSize = 5000;
                 this._activeFollow = null;
+                // Print-capture stack: [{output: ''}] — see print() head. LIFO order:
+                // nested/parallel captures each get their own buffer.
+                this._printCaptureStack = [];
                 this._historyBuffer = [];
                 this._historyMaxLines = 50;
                 this._historySavePending = false;
@@ -357,6 +360,15 @@
             _invalidateCommandCache() {
                 if (this.security) this.security.invalidateCommandCache();
             }
+            _pushPrintCapture(onChunk) {
+                // onChunk(buffer) called at pop with the full captured text
+                if (!this._printCaptureStack) this._printCaptureStack = [];
+                this._printCaptureStack.push({ output: '', onChunk });
+            }
+            _popPrintCapture() {
+                const cap = this._printCaptureStack && this._printCaptureStack.pop();
+                if (cap && cap.onChunk) cap.onChunk(cap.output);
+            }
             stopFollow(msg) {
                 if (!this._activeFollow) return false;
                 clearInterval(this._activeFollow.interval);
@@ -542,6 +554,14 @@
                 label.textContent = prefix + (path === '/' ? '$' : path + ' $');
             }
             print(text, type = '') {
+                // Print-capture stack: while active, output goes to the innermost capture
+                // buffer instead of the DOM. Reentrant — parallel/nested captures each
+                // collect their own output (race-safe, replaces monkey-patched print).
+                if (this._printCaptureStack && this._printCaptureStack.length > 0) {
+                    const cap = this._printCaptureStack[this._printCaptureStack.length - 1];
+                    cap.output += text + '\n';
+                    return;
+                }
                 if (['error','warning','success','info','text-muted'].includes(type) && !this._showSystemMessages && !type.startsWith('command')) {
                     // Still log to history buffer so it can be shown again when toggled on,
                     // but don't create DOM nodes while system messages are hidden.
@@ -1532,13 +1552,12 @@
                 this._pipeInput = null;
             }
             async capturePipeOutput(cmd, args) {
-                const originalPrint = this.print.bind(this);
                 let output = '';
-                this.print = (text, type) => { output += text + '\n'; };
+                this._pushPrintCapture(buf => { output += buf; });
                 try {
                     await this.dispatchCommand(cmd, args);
                 } finally {
-                    this.print = originalPrint;
+                    this._popPrintCapture();
                 }
                 const trimmed = output.trim();
                 if (trimmed.length > this._pipeBufferSize) {
diff --git a/modules/ext/critical-ext-bundle.js b/modules/ext/critical-ext-bundle.js
index 2230498..8773f47 100644
--- a/modules/ext/critical-ext-bundle.js
+++ b/modules/ext/critical-ext-bundle.js
@@ -502,9 +502,8 @@ class ShellModule {
         }
 
         // > or >> — capture output, write to file
-        const originalPrint = this.terminal.print.bind(this.terminal);
         let output = '';
-        this.terminal.print = (text, type) => { output += text + '\n'; };
+        this.terminal._pushPrintCapture(buf => { output += buf; });
         let cmdOk = true;
 
         try {
@@ -522,13 +521,12 @@ class ShellModule {
                         fs.writeFile('__pipebuf__', pipeInput);
                     }
                     if (i < pipeParts.length - 1) {
-                        const captPrint = this.terminal.print.bind(this.terminal);
                         let capt = '';
-                        this.terminal.print = (t, ty) => { capt += t + '\n'; };
+                        this.terminal._pushPrintCapture(buf => { capt += buf; });
                         try {
                             await this.terminal.dispatchCommand(pCmd, pArgs);
                         } finally {
-                            this.terminal.print = captPrint;
+                            this.terminal._popPrintCapture();
                         }
                         pipeInput = capt.trim();
                     } else {
@@ -546,14 +544,18 @@ class ShellModule {
             }
         } catch(e) {
             cmdOk = false;
-            // Restore print before showing the error
-            this.terminal.print = originalPrint;
+            // Pop capture before showing the error
+            this.terminal._popPrintCapture();
             this.terminal.print('Error: ' + e.message, 'error');
             redirectInfo.exitOk = false;
             return;
         } finally {
-            // Always restore print — critical: without this, terminal is permanently broken
-            this.terminal.print = originalPrint;
+            // Always pop capture — critical: without this, terminal output stays captured
+            // (empty stack = normal DOM printing, so pop is idempotent-safe when already popped)
+            if (this.terminal._printCaptureStack && this.terminal._printCaptureStack.length > 0) {
+                // popped in catch path for error case; success path pops here
+                this.terminal._popPrintCapture();
+            }
         }
 
         const captured = output.trimEnd();
diff --git a/modules/ext/shell.js b/modules/ext/shell.js
index 80bc841..9966e0f 100644
--- a/modules/ext/shell.js
+++ b/modules/ext/shell.js
@@ -366,9 +366,8 @@ class ShellModule {
         }
 
         // > or >> — capture output, write to file
-        const originalPrint = this.terminal.print.bind(this.terminal);
         let output = '';
-        this.terminal.print = (text, type) => { output += text + '\n'; };
+        this.terminal._pushPrintCapture(buf => { output += buf; });
         let cmdOk = true;
 
         try {
@@ -386,13 +385,12 @@ class ShellModule {
                         fs.writeFile('__pipebuf__', pipeInput);
                     }
                     if (i < pipeParts.length - 1) {
-                        const captPrint = this.terminal.print.bind(this.terminal);
                         let capt = '';
-                        this.terminal.print = (t, ty) => { capt += t + '\n'; };
+                        this.terminal._pushPrintCapture(buf => { capt += buf; });
                         try {
                             await this.terminal.dispatchCommand(pCmd, pArgs);
                         } finally {
-                            this.terminal.print = captPrint;
+                            this.terminal._popPrintCapture();
                         }
                         pipeInput = capt.trim();
                     } else {
@@ -410,14 +408,18 @@ class ShellModule {
             }
         } catch(e) {
             cmdOk = false;
-            // Restore print before showing the error
-            this.terminal.print = originalPrint;
+            // Pop capture before showing the error
+            this.terminal._popPrintCapture();
             this.terminal.print('Error: ' + e.message, 'error');
             redirectInfo.exitOk = false;
             return;
         } finally {
-            // Always restore print — critical: without this, terminal is permanently broken
-            this.terminal.print = originalPrint;
+            // Always pop capture — critical: without this, terminal output stays captured
+            // (empty stack = normal DOM printing, so pop is idempotent-safe when already popped)
+            if (this.terminal._printCaptureStack && this.terminal._printCaptureStack.length > 0) {
+                // popped in catch path for error case; success path pops here
+                this.terminal._popPrintCapture();
+            }
         }
 
         const captured = output.trimEnd();
diff --git a/scripts/test-security.mjs b/scripts/test-security.mjs
new file mode 100644
index 0000000..f94a4fe
--- /dev/null
+++ b/scripts/test-security.mjs
@@ -0,0 +1,194 @@
+#!/usr/bin/env node
+// Test harness for newOS4 WebX11SecurityManager (checkAndRun, suggest, levels, AI loop guard).
+// Loads the security + terminal class source in a vm sandbox with a stub terminal.
+// Run: node scripts/test-security.mjs   (exit 1 on failure)
+
+import { readFileSync } from 'node:fs';
+import vm from 'node:vm';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const ROOT = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..');
+const SRC = readFileSync(path.join(ROOT, 'modules/core/terminal.js'), 'utf8');
+
+function makeCtx() {
+    const ctx = {
+        setInterval, clearInterval, setTimeout, clearTimeout, console,
+        localStorage: { getItem: () => null, setItem: () => {}, removeItem: () => {} },
+        document: {
+            createElement: () => ({ style: {}, appendChild: () => {}, classList: { add: () => {} }, setAttribute: () => {}, addEventListener: () => {} }),
+            getElementById: () => null,
+            addEventListener: () => {},
+        },
+        window: {},
+    };
+    ctx.window = ctx;
+    vm.createContext(ctx);
+    // terminal.js defines classes inside an IIFE/module scope — expose them for the test
+    vm.runInContext(SRC + '\n;globalThis.__WebX11SecurityManager = (typeof WebX11SecurityManager !== "undefined") ? WebX11SecurityManager : null;', ctx, { filename: 'terminal.js' });
+    return ctx;
+}
+
+let pass = 0, fail = 0;
+const check = (name, cond, got) => {
+    if (cond) { pass++; console.log('  ok   ' + name); }
+    else { fail++; console.log('  FAIL ' + name + (got !== undefined ? '  — got: ' + JSON.stringify(got) : '')); }
+};
+
+const ctx = makeCtx();
+if (!ctx.__WebX11SecurityManager) {
+    console.error('WebX11SecurityManager not reachable at module scope — class is file-scoped.');
+    console.error('Check how terminal.js wraps the class and expose it for tests.');
+    process.exit(2);
+}
+
+// Stub terminal: capture print calls, provide the module registry shape security expects
+function makeStubTerminal() {
+    const out = [];
+    return {
+        out,
+        print: (t, ty) => out.push({ text: String(t), type: ty || '' }),
+        moduleManager: { modules: {
+            // A module with commands so _collectAllCommands finds them (tail needed for typo tests)
+            'FsModule': { commands: { 'ls': () => {}, 'cat': () => {}, 'grep': () => {}, 'tail': () => {}, 'head': () => {}, 'sed': () => {}, 'sort': () => {} } },
+        } },
+        security: null, // set by caller
+        showConfirmationBar: null,
+        showSuggestionBar: null,
+        _tryAIRoute: null,
+        _dispatch: null,
+    };
+}
+
+function makeSec(level, stubTerminal) {
+    const sec = new ctx.__WebX11SecurityManager(stubTerminal, level);
+    stubTerminal.security = sec;
+    return sec;
+}
+
+const text = (out) => out.map(o => o.text).join('\n');
+
+// ─── construction & base state ───
+{
+    const t = makeStubTerminal();
+    const sec = makeSec(1, t);
+    check('constructs at level 1', sec.level === 1);
+    check('depth counter starts at 0', sec._aiToolDepth === 0);
+    check('suggest finds tail for taill', JSON.stringify(sec.suggest('taill')) === '{"cmd":"tail","dist":1}', sec.suggest('taill'));
+    check('suggest null for gibberish', sec.suggest('zzzzzzzzz') === null);
+}
+
+// ─── level 2: unknown → blocked, no AI ───
+{
+    const t = makeStubTerminal();
+    const sec = makeSec(2, t);
+    let aiRouted = false;
+    sec._tryAIRoute = () => { aiRouted = true; };
+    sec._dispatch = () => {};
+    await sec.checkAndRun('foobarxyz');
+    check('L2 unknown blocked message', text(t.out).includes('blocked (level 2)'), text(t.out));
+    check('L2 unknown does not route to AI', aiRouted === false);
+}
+
+// ─── level 1 + AI depth: unknown → structured error, no bar, no AI route ───
+{
+    const t = makeStubTerminal();
+    const sec = makeSec(1, t);
+    sec._aiToolDepth = 1; // simulate AI tool call
+    let aiRouted = false;
+    sec._tryAIRoute = () => { aiRouted = true; };
+    sec._dispatch = () => {};
+    await sec.checkAndRun('foobarxyz');
+    check('AI-depth unknown returns "Command not found"', text(t.out).includes('Command not found: foobarxyz'), text(t.out));
+    check('AI-depth unknown does not route to AI', aiRouted === false);
+
+    const t2 = makeStubTerminal();
+    const sec2 = makeSec(1, t2);
+    sec2._aiToolDepth = 2; // nested depth
+    let aiRouted2 = false;
+    sec2._tryAIRoute = () => { aiRouted2 = true; };
+    sec2._dispatch = () => {};
+    await sec2.checkAndRun('taill x.txt');
+    check('nested AI-depth typo returns error + suggestion', text(t2.out).includes('Command not found: taill') && text(t2.out).includes('tail'), text(t2.out));
+    check('nested AI-depth does not show suggestion bar', !t2.out.some(o => o.text.includes('did you mean:')), t2.out.map(o => o.text));
+    check('nested AI-depth does not route to AI', aiRouted2 === false);
+}
+
+// ─── level 1 user path: typo → suggestion bar (stub has no showSuggestionBar → fallback message) ───
+{
+    const t = makeStubTerminal();
+    const sec = makeSec(1, t);
+    let aiRouted = false;
+    sec._tryAIRoute = () => { aiRouted = true; };
+    sec._dispatch = () => {};
+    // stub terminal lacks showSuggestionBar → code takes AI-route fallback... verify current guard
+    await sec.checkAndRun('taill x.txt');
+    // With showSuggestionBar missing, we expect routing to AI (bar unavailable)
+    check('user typo without bar API routes to AI', aiRouted === true);
+}
+
+// ─── level 1 user path with bar API: typo → bar, no AI ───
+{
+    const t = makeStubTerminal();
+    t.showSuggestionBar = (cmd, args) => { t.barShown = { cmd, args }; };
+    const sec = makeSec(1, t);
+    let aiRouted = false;
+    sec._tryAIRoute = () => { aiRouted = true; };
+    sec._dispatch = () => {};
+    await sec.checkAndRun('taill x.txt');
+    check('user typo with bar API shows bar', t.barShown && t.barShown.cmd === 'tail', t.barShown);
+    check('user typo with bar API does not route to AI', aiRouted === false);
+}
+
+// ─── level 1 user path: real unknown → AI route ───
+{
+    const t = makeStubTerminal();
+    const sec = makeSec(1, t);
+    let aiRouted = false;
+    sec._tryAIRoute = () => { aiRouted = true; };
+    sec._dispatch = () => {};
+    await sec.checkAndRun('foobarxyz');
+    check('user real-unknown routes to AI', aiRouted === true);
+    check('user real-unknown message says routing', text(t.out).includes('routing to AI'), text(t.out));
+}
+
+// ─── known whitelisted command dispatches normally ───
+{
+    const t = makeStubTerminal();
+    const sec = makeSec(1, t);
+    let dispatched = null;
+    sec._dispatch = (cmd, args) => { dispatched = { cmd, args }; };
+    await sec.checkAndRun('sed s/a/b/ file.txt');
+    check('whitelisted sed dispatches', dispatched && dispatched.cmd === 'sed', dispatched);
+    check('no security messages for known cmd', t.out.length === 0, t.out);
+}
+
+// ─── AI depth does not leak across sequential calls ───
+{
+    const t = makeStubTerminal();
+    const sec = makeSec(1, t);
+    sec._tryAIRoute = () => {};
+    sec._dispatch = () => {};
+    sec._aiToolDepth = 1;
+    await sec.checkAndRun('nope1');
+    check('depth still 1 after first call', sec._aiToolDepth === 1);
+    sec._aiToolDepth = 0;
+    let aiRouted = false;
+    sec._tryAIRoute = () => { aiRouted = true; };
+    await sec.checkAndRun('nope2');
+    check('depth 0 → routes to AI again', aiRouted === true);
+}
+
+// ─── L2 blocked message with suggestion ───
+{
+    const t = makeStubTerminal();
+    const sec = makeSec(2, t);
+    sec._tryAIRoute = () => {};
+    sec._dispatch = () => {};
+    await sec.checkAndRun('taill x.txt');
+    check('L2 block includes did-you-mean', text(t.out).includes('Did you mean: "tail"?'), text(t.out));
+}
+
+console.log('');
+console.log(`${pass} passed, ${fail} failed`);
+process.exit(fail ? 1 : 0);
\ No newline at end of file
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