Add SchemaLlmTool and TextLlmTool

src/core/llm/SchemaLlmTool.ts

@@ -0,0 +1,60 @@
+import type { ZodSchema } from 'zod';
+import { LlmTool } from './LlmTool';
+import type { RunContext } from './RunContext';
+
+export class LlmOutputParseError extends Error {
+  constructor(
+    message: string,
+    readonly raw: string
+  ) {
+    super(message);
+    this.name = 'LlmOutputParseError';
+  }
+}
+
+export abstract class SchemaLlmTool<TInput, TOutput> extends LlmTool<TInput, TOutput> {
+  protected abstract readonly outputSchema: ZodSchema<TOutput>;
+
+  protected parseOutput(raw: string, _ctx: RunContext): TOutput {
+    const json = extractJson(raw);
+    const result = this.outputSchema.safeParse(json);
+    if (!result.success) {
+      throw new LlmOutputParseError(`Output failed schema validation: ${result.error.message}`, raw);
+    }
+    return result.data;
+  }
+}
+
+export function extractJson(content: string): unknown {
+  let text = content.trim();
+
+  const fenceStart = text.indexOf('```');
+  if (fenceStart !== -1) {
+    text = text.slice(fenceStart);
+    text = text.replace(/^```json/, '').replace(/^```/, '');
+    const fenceEnd = text.indexOf('```');
+    if (fenceEnd !== -1) {
+      text = text.slice(0, fenceEnd);
+    }
+    text = text.trim();
+  }
+
+  const arrayStart = text.indexOf('[');
+  const objectStart = text.indexOf('{');
+  const starts = [arrayStart, objectStart].filter((i) => i !== -1);
+  if (starts.length === 0) {
+    throw new LlmOutputParseError(`No JSON found in LLM response: ${content}`, content);
+  }
+  const start = Math.min(...starts);
+  const isArray = start === arrayStart;
+  const end = isArray ? text.lastIndexOf(']') : text.lastIndexOf('}');
+  if (end === -1 || end <= start) {
+    throw new LlmOutputParseError(`No JSON found in LLM response: ${content}`, content);
+  }
+
+  try {
+    return JSON.parse(text.slice(start, end + 1));
+  } catch (err) {
+    throw new LlmOutputParseError(`Failed to parse JSON from LLM response: ${String(err)}`, content);
+  }
+}

src/core/llm/TextLlmTool.ts

@@ -0,0 +1,8 @@
+import { LlmTool } from './LlmTool';
+import type { RunContext } from './RunContext';
+
+export abstract class TextLlmTool<TInput> extends LlmTool<TInput, string> {
+  protected parseOutput(raw: string, _ctx: RunContext): string {
+    return raw.trim();
+  }
+}