feat: claude one-shot port from nanobot python codebase (v0.1.4.post4)

src/agent/tools/base.ts

@@ -0,0 +1,55 @@
+import type { ToolDefinition } from '../../provider/types.ts';
+
+/** Safely extract a string from tool args (avoids no-base-to-string lint). */
+export function strArg(args: Record<string, unknown>, key: string, fallback = ''): string {
+  const v = args[key];
+  return typeof v === 'string' ? v : fallback;
+}
+
+export interface Tool {
+  readonly name: string;
+  readonly description: string;
+  /** JSON Schema `properties` object for the tool's parameters. */
+  readonly parameters: Record<string, unknown>;
+  /** Which parameters are required. Defaults to all keys if not set. */
+  readonly required?: string[];
+  execute(args: Record<string, unknown>): Promise<string>;
+}
+
+export class ToolRegistry {
+  private _tools = new Map<string, Tool>();
+
+  register(tool: Tool): void {
+    this._tools.set(tool.name, tool);
+  }
+
+  get(name: string): Tool | undefined {
+    return this._tools.get(name);
+  }
+
+  getDefinitions(): ToolDefinition[] {
+    return [...this._tools.values()].map((t) => ({
+      type: 'function' as const,
+      function: {
+        name: t.name,
+        description: t.description,
+        parameters: {
+          type: 'object',
+          properties: t.parameters,
+          required: t.required ?? Object.keys(t.parameters),
+        },
+      },
+    }));
+  }
+
+  async execute(name: string, args: Record<string, unknown>): Promise<string> {
+    const tool = this._tools.get(name);
+    if (!tool) return `Error: unknown tool "${name}"`;
+
+    try {
+      return await tool.execute(args);
+    } catch (err) {
+      return `Error: ${String(err)}\n[Analyze the error above and retry with a different approach if needed.]`;
+    }
+  }
+}