chore: TFY sandbox should discover working directory before writing files

.changeset/tfy-sandbox-pwd-instructions.md

@@ -0,0 +1,5 @@
+---
+"@truefoundry/trueforge-core": patch
+---
+
+Add TFY sandbox agent instructions to discover the working directory via `pwd` before writing files.

packages/trueforge-core/src/core/sandbox/provider/TFYSandboxProvider.ts

@@ -251,8 +251,9 @@ export class TFYSandboxProvider implements SandboxProvider {
   getAdditionalInstructions(): string {
     return dedent`
     SANDBOX RULES:
-    - uploads, skills, and tool-results live in the sandbox working directory (not /tmp or /opt).
-    - ALL file creation and writes MUST stay within the sandbox working directory.
+    - The Agent's first sandbox command should be \`pwd\` to discover the working directory.
+    - uploads, skills, and tool-results live in that working directory (not /tmp or /opt).
+    - ALL file creation and writes MUST stay within that working directory.
     - The Agent must NOT write to /tmp/, ~/, or any absolute path outside the working directory.
   `;
   }

packages/trueforge-core/tests/core/sandbox/provider/tfyLayout.test.ts

@@ -26,7 +26,10 @@ describe('TFYSandboxProvider layout', () => {
     expect(install.remotePath.startsWith('/')).toBe(false);
     expect(install.pathBinSymlink).toBeUndefined();
     const instructions = provider.getAdditionalInstructions();
-    expect(instructions).toContain('uploads, skills, and tool-results live in the sandbox working directory');
+    expect(instructions).toContain(
+      "The Agent's first sandbox command should be `pwd` to discover the working directory.",
+    );
+    expect(instructions).toContain('uploads, skills, and tool-results live in that working directory');
     expect(instructions).not.toContain('/data/sandboxes');
   });