feat(memory): persist auto-memory scratchpad for skill extraction (#25873)

packages/core/src/services/sessionScratchpadUtils.ts

@@ -0,0 +1,155 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { SHELL_TOOL_NAME } from '../tools/definitions/base-declarations.js';
+
+const WORKFLOW_PART_SEPARATOR = ' | ';
+const TOOL_SEQUENCE_SEPARATOR = ' -> ';
+const SHELL_ASSIGNMENT_REGEX = /^[A-Za-z_][A-Za-z0-9_]*=/;
+const SAFE_COMMAND_NAME_REGEX = /^[A-Za-z0-9_.@+-]+$/;
+const SAFE_TOOL_SEQUENCE_ENTRY_REGEX = /^[A-Za-z_][A-Za-z0-9_:.]*$/;
+
+function tokenizeShellCommand(command: string): string[] {
+  const tokens: string[] = [];
+  let currentToken = '';
+  let quote: '"' | "'" | '`' | undefined;
+
+  for (let i = 0; i < command.length; i++) {
+    const char = command[i];
+
+    if (quote) {
+      if (char === quote) {
+        quote = undefined;
+        continue;
+      }
+
+      if (quote === '"' && char === '\\' && i + 1 < command.length) {
+        currentToken += command[i + 1];
+        i++;
+        continue;
+      }
+
+      currentToken += char;
+      continue;
+    }
+
+    if (char === ' ' || char === '\t' || char === '\n' || char === '\r') {
+      if (currentToken) {
+        tokens.push(currentToken);
+        currentToken = '';
+      }
+      continue;
+    }
+
+    if (char === '"' || char === "'" || char === '`') {
+      quote = char;
+      continue;
+    }
+
+    currentToken += char;
+  }
+
+  if (currentToken) {
+    tokens.push(currentToken);
+  }
+
+  return tokens;
+}
+
+function getSafeCommandName(token: string): string | undefined {
+  if (!token || SHELL_ASSIGNMENT_REGEX.test(token)) {
+    return undefined;
+  }
+
+  const pathParts = token.split(/[/\\]/).filter(Boolean);
+  const basename = pathParts[pathParts.length - 1] ?? token;
+  if (!basename || basename.includes('://')) {
+    return 'shell';
+  }
+
+  return SAFE_COMMAND_NAME_REGEX.test(basename) ? basename : 'shell';
+}
+
+export function summarizeShellCommandForScratchpad(
+  command: string,
+): string | undefined {
+  const normalized = command.replace(/\s+/g, ' ').trim();
+  if (normalized.length === 0) {
+    return undefined;
+  }
+
+  for (const token of tokenizeShellCommand(normalized)) {
+    const commandName = getSafeCommandName(token);
+    if (commandName) {
+      return commandName;
+    }
+  }
+
+  return undefined;
+}
+
+function sanitizeWorkflowToolSequenceEntry(entry: string): string | undefined {
+  const trimmed = entry.trim();
+  if (!trimmed) {
+    return undefined;
+  }
+
+  const shellPrefix = `${SHELL_TOOL_NAME}:`;
+  if (trimmed.startsWith(shellPrefix)) {
+    const command = trimmed.slice(shellPrefix.length).trim();
+    const commandSummary = summarizeShellCommandForScratchpad(command);
+    return commandSummary
+      ? `${SHELL_TOOL_NAME}: ${commandSummary}`
+      : SHELL_TOOL_NAME;
+  }
+
+  if (
+    trimmed === SHELL_TOOL_NAME ||
+    SAFE_TOOL_SEQUENCE_ENTRY_REGEX.test(trimmed)
+  ) {
+    return trimmed;
+  }
+
+  return undefined;
+}
+
+export function sanitizeWorkflowSummaryForScratchpad(summary: string): string {
+  const normalized = summary.replace(/\s+/g, ' ').trim();
+  if (!normalized.includes(`${SHELL_TOOL_NAME}:`)) {
+    return normalized;
+  }
+
+  const sanitizedParts: string[] = [];
+  for (const part of normalized.split(WORKFLOW_PART_SEPARATOR)) {
+    const trimmed = part.trim();
+    if (!trimmed) {
+      continue;
+    }
+
+    if (trimmed.includes(`${SHELL_TOOL_NAME}:`)) {
+      const sanitizedToolSequence = trimmed
+        .split(TOOL_SEQUENCE_SEPARATOR)
+        .map(sanitizeWorkflowToolSequenceEntry)
+        .filter((entry): entry is string => Boolean(entry));
+      if (sanitizedToolSequence.length > 0) {
+        sanitizedParts.push(
+          sanitizedToolSequence.join(TOOL_SEQUENCE_SEPARATOR),
+        );
+      }
+      continue;
+    }
+
+    if (
+      trimmed.startsWith('paths ') ||
+      trimmed === 'validated' ||
+      trimmed === 'validation failed'
+    ) {
+      sanitizedParts.push(trimmed);
+    }
+  }
+
+  return sanitizedParts.join(WORKFLOW_PART_SEPARATOR);
+}