fix(bash): honor explicit working directories

extensions/bash-cwd/index.ts

@@ -0,0 +1,89 @@
+import { stat } from "node:fs/promises";
+import { resolve } from "node:path";
+
+import {
+  createBashToolDefinition,
+  type ExtensionAPI,
+  type ExtensionContext,
+} from "@earendil-works/pi-coding-agent";
+import { type Static, Type } from "typebox";
+
+const bashCwdParameters = Type.Object({
+  command: Type.String({ description: "Shell command to execute" }),
+  cwd: Type.Optional(
+    Type.String({
+      description:
+        "Working directory. Relative paths resolve from the session working directory.",
+    }),
+  ),
+  timeout: Type.Optional(
+    Type.Number({ description: "Timeout in seconds (optional, no default timeout)" }),
+  ),
+});
+
+type BashCwdInput = Static<typeof bashCwdParameters>;
+type BuiltInBashDefinition = ReturnType<typeof createBashToolDefinition>;
+type BuiltInBashExecute = BuiltInBashDefinition["execute"];
+
+async function resolveWorkingDirectory(
+  sessionCwd: string,
+  requestedCwd: string | undefined,
+): Promise<string> {
+  const cwd = resolve(sessionCwd, requestedCwd ?? ".");
+
+  let metadata;
+  try {
+    metadata = await stat(cwd);
+  } catch (error) {
+    if ((error as NodeJS.ErrnoException).code === "ENOENT") {
+      throw new Error(
+        `Working directory does not exist: ${cwd}\nCannot execute bash commands.`,
+      );
+    }
+    throw error;
+  }
+
+  if (!metadata.isDirectory()) {
+    throw new Error(
+      `Working directory is not a directory: ${cwd}\nCannot execute bash commands.`,
+    );
+  }
+
+  return cwd;
+}
+
+export function createContextualBashTool() {
+  const baseTool = createBashToolDefinition(process.cwd());
+
+  return {
+    ...baseTool,
+    description:
+      `${baseTool.description} The optional cwd may be absolute or relative to the session working directory.`,
+    parameters: bashCwdParameters,
+    async execute(
+      toolCallId: Parameters<BuiltInBashExecute>[0],
+      params: BashCwdInput,
+      signal: Parameters<BuiltInBashExecute>[2],
+      onUpdate: Parameters<BuiltInBashExecute>[3],
+      ctx: ExtensionContext,
+    ) {
+      if (!ctx) {
+        throw new Error("Bash execution context is unavailable");
+      }
+
+      const cwd = await resolveWorkingDirectory(ctx.cwd, params.cwd);
+      const contextualTool = createBashToolDefinition(cwd);
+      return contextualTool.execute(
+        toolCallId,
+        { command: params.command, timeout: params.timeout },
+        signal,
+        onUpdate,
+        ctx,
+      );
+    },
+  };
+}
+
+export default function bashCwd(pi: ExtensionAPI): void {
+  pi.registerTool(createContextualBashTool());
+}