fix(ast-grep): restore pattern hints in tools

src/tools/ast-grep/tools.test.ts

@@ -0,0 +1,55 @@
+/// <reference types="bun-types" />
+
+import { beforeEach, describe, expect, it, mock } from "bun:test"
+import { AST_GREP_REPLACE_DESCRIPTION, AST_GREP_SEARCH_DESCRIPTION } from "./tool-descriptions"
+
+const runSgMock = mock(async () => ({
+  matches: [],
+  totalMatches: 0,
+  truncated: false,
+}))
+
+mock.module("./cli", () => ({
+  runSg: runSgMock,
+}))
+
+import { createAstGrepTools } from "./tools"
+
+describe("createAstGrepTools", () => {
+  beforeEach(() => {
+    runSgMock.mockClear()
+  })
+
+  it("#given the production tool factory #when creating tools #then exposes shared ast-grep descriptions", () => {
+    // given / when
+    const tools = createAstGrepTools({ directory: "/repo" } as never)
+
+    // then
+    expect(tools.ast_grep_search.description).toBe(AST_GREP_SEARCH_DESCRIPTION)
+    expect(tools.ast_grep_replace.description).toBe(AST_GREP_REPLACE_DESCRIPTION)
+    expect(tools.ast_grep_search.description).toContain("NOT regex")
+  })
+
+  it("#given empty search results from a regex-shaped pattern #when executing #then appends the pattern hint", async () => {
+    // given
+    const tools = createAstGrepTools({ directory: "/repo" } as never)
+
+    // when
+    const output = await tools.ast_grep_search.execute(
+      { pattern: "foo|bar", lang: "typescript" },
+      {},
+    )
+
+    // then
+    expect(output).toContain("No matches found")
+    expect(output).toContain("alternation")
+    expect(output).toContain("grep")
+    expect(runSgMock).toHaveBeenCalledWith({
+      pattern: "foo|bar",
+      lang: "typescript",
+      paths: ["/repo"],
+      globs: undefined,
+      context: undefined,
+    })
+  })
+})