diff --git a/bin/gstack-open-url b/bin/gstack-open-url
new file mode 100644
index 000000000..68508f861
--- /dev/null
+++ b/bin/gstack-open-url
@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+# gstack-open-url — cross-platform URL opener
+#
+# Usage:
+#   gstack-open-url <url>  — open URL in default browser
+#
+# Supports macOS (open), Linux (xdg-open), and Windows (start)
+#
+# Env overrides (for testing):
+#   GSTACK_OPEN_CMD  — override the open command
+set -euo pipefail
+
+URL="${1:-}"
+
+if [ -z "$URL" ]; then
+  echo "Usage: gstack-open-url <url>" >&2
+  exit 1
+fi
+
+# Allow explicit override via environment
+if [ -n "${GSTACK_OPEN_CMD:-}" ]; then
+  $GSTACK_OPEN_CMD "$URL"
+  exit 0
+fi
+
+# Detect platform and use appropriate command
+case "$(uname -s)" in
+  Darwin)
+    # macOS
+    open "$URL"
+    ;;
+  Linux)
+    # Linux - use xdg-open
+    if command -v xdg-open >/dev/null 2>&1; then
+      xdg-open "$URL"
+    else
+      echo "Error: xdg-open not found. Install xdg-utils or set GSTACK_OPEN_CMD." >&2
+      exit 1
+    fi
+    ;;
+  CYGWIN*|MINGW*|MSYS*)
+    # Windows
+    start "" "$URL"
+    ;;
+  *)
+    echo "Error: Unknown platform $(uname -s). Set GSTACK_OPEN_CMD to override." >&2
+    exit 1
+    ;;
+esac
diff --git a/browse/src/sidebar-agent.ts b/browse/src/sidebar-agent.ts
index 6eb2cebbb..05fa63d75 100644
--- a/browse/src/sidebar-agent.ts
+++ b/browse/src/sidebar-agent.ts
@@ -160,7 +160,7 @@ async function askClaude(queueEntry: any): Promise<void> {
   return new Promise((resolve) => {
     // Build args fresh — don't trust --resume from queue (session may be stale)
     let claudeArgs = ['-p', prompt, '--output-format', 'stream-json', '--verbose',
-      '--allowedTools', 'Bash,Read,Glob,Grep'];
+      '--allowedTools', 'Bash,Read,Glob,Grep,Write'];
 
     // Validate cwd exists — queue may reference a stale worktree
     let effectiveCwd = cwd || process.cwd();
@@ -186,7 +186,11 @@ async function askClaude(queueEntry: any): Promise<void> {
       }
     });
 
-    proc.stderr.on('data', () => {}); // Claude logs to stderr, ignore
+    // Capture stderr for error reporting
+    let stderrBuffer = '';
+    proc.stderr.on('data', (data: Buffer) => {
+      stderrBuffer += data.toString();
+    });
 
     proc.on('close', (code) => {
       if (buffer.trim()) {
@@ -199,7 +203,8 @@ async function askClaude(queueEntry: any): Promise<void> {
     });
 
     proc.on('error', (err) => {
-      sendEvent({ type: 'agent_error', error: err.message }).then(() => {
+      const errorMsg = stderrBuffer ? `${err.message}\nStderr: ${stderrBuffer}` : err.message;
+      sendEvent({ type: 'agent_error', error: errorMsg }).then(() => {
         isProcessing = false;
         resolve();
       });
@@ -209,7 +214,10 @@ async function askClaude(queueEntry: any): Promise<void> {
     const timeoutMs = parseInt(process.env.SIDEBAR_AGENT_TIMEOUT || '300000', 10);
     setTimeout(() => {
       try { proc.kill(); } catch {}
-      sendEvent({ type: 'agent_error', error: `Timed out after ${timeoutMs / 1000}s` }).then(() => {
+      const errorMsg = stderrBuffer
+        ? `Timed out after ${timeoutMs / 1000}s\nStderr: ${stderrBuffer}`
+        : `Timed out after ${timeoutMs / 1000}s`;
+      sendEvent({ type: 'agent_error', error: errorMsg }).then(() => {
         isProcessing = false;
         resolve();
       });
diff --git a/scripts/resolvers/preamble.ts b/scripts/resolvers/preamble.ts
index 4e5092f8a..f4d6a9969 100644
--- a/scripts/resolvers/preamble.ts
+++ b/scripts/resolvers/preamble.ts
@@ -33,6 +33,8 @@ REPO_MODE=\${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
+_SEARCH_SEEN=$([ -f ~/.gstack/.search-intro-seen ] && echo "yes" || echo "no")
+echo "SEARCH_INTRO: $_SEARCH_SEEN"
 _TEL=$(${ctx.paths.binDir}/gstack-config get telemetry 2>/dev/null || true)
 _TEL_PROMPTED=$([ -f ~/.gstack/.telemetry-prompted ] && echo "yes" || echo "no")
 _TEL_START=$(date +%s)
@@ -61,18 +63,33 @@ of \`/qa\`, \`/gstack-ship\` instead of \`/ship\`). Disk paths are unaffected 
 If output shows \`UPGRADE_AVAILABLE <old> <new>\`: read \`${ctx.paths.skillRoot}/gstack-upgrade/SKILL.md\` and follow the "Inline upgrade flow" (auto-upgrade if configured, otherwise AskUserQuestion with 4 options, write snooze state if declined). If \`JUST_UPGRADED <from> <to>\`: tell user "Running gstack v{to} (just updated!)" and continue.`;
 }
 
-function generateLakeIntro(): string {
+function generateLakeIntro(ctx: TemplateContext): string {
   return `If \`LAKE_INTRO\` is \`no\`: Before continuing, introduce the Completeness Principle.
 Tell the user: "gstack follows the **Boil the Lake** principle — always do the complete
 thing when AI makes the marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean"
 Then offer to open the essay in their default browser:
 
 \`\`\`bash
-open https://garryslist.org/posts/boil-the-ocean
+${ctx.paths.binDir}/gstack-open-url https://garryslist.org/posts/boil-the-ocean
 touch ~/.gstack/.completeness-intro-seen
 \`\`\`
 
-Only run \`open\` if the user says yes. Always run \`touch\` to mark as seen. This only happens once.`;
+Only run \`gstack-open-url\` if the user says yes. Always run \`touch\` to mark as seen. This only happens once.`;
+}
+
+function generateSearchIntro(ctx: TemplateContext): string {
+  return `If \`SEARCH_INTRO\` is \`no\`: Before continuing, introduce the Search Before Building principle.
+Tell the user: "gstack follows the **Search Before Building** principle — always search
+for existing solutions before building from scratch. When the conventional approach is
+wrong for your specific case, that's where brilliance occurs. Read more: https://garryslist.org/posts/search-before-building"
+Then offer to open the essay in their default browser:
+
+\`\`\`bash
+${ctx.paths.binDir}/gstack-open-url https://garryslist.org/posts/search-before-building
+touch ~/.gstack/.search-intro-seen
+\`\`\`
+
+Only run \`gstack-open-url\` if the user says yes. Always run \`touch\` to mark as seen. This only happens once.`;
 }
 
 function generateTelemetryPrompt(ctx: TemplateContext): string {
@@ -477,12 +494,12 @@ export function generatePreamble(ctx: TemplateContext): string {
   const sections = [
     generatePreambleBash(ctx),
     generateUpgradeCheck(ctx),
-    generateLakeIntro(),
+    generateLakeIntro(ctx),
     generateTelemetryPrompt(ctx),
     generateProactivePrompt(ctx),
     generateVoiceDirective(tier),
     ...(tier >= 2 ? [generateAskUserFormat(ctx), generateCompletenessSection()] : []),
-    ...(tier >= 3 ? [generateRepoModeSection(), generateSearchBeforeBuildingSection(ctx)] : []),
+    ...(tier >= 3 ? [generateRepoModeSection(), generateSearchBeforeBuildingSection(ctx), generateSearchIntro(ctx)] : []),
     generateContributorMode(),
     generateCompletionStatus(),
   ];