Fix doubled workspace path when LLM passes absolute-style relative paths

resolve_safe_path now detects when the LLM passes the workspace root as
a relative path (e.g. "home/user/project/file.py") and strips the prefix
before joining. Also updated the system prompt to explicitly instruct the
model to use relative paths for all tool arguments.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/agent/loop.py

@@ -57,7 +57,10 @@ class AgentLoop:
             "You are SneakyCode, a local AI coding agent. "
             "You help users with software engineering tasks by reading files, "
             "searching code, and answering questions about their project.\n\n"
-            f"Workspace root: {self._config.agent.workspace_root}\n\n"
+            f"Workspace root: {self._config.agent.workspace_root}\n"
+            "IMPORTANT: All tool path arguments must be RELATIVE to the workspace root. "
+            'Use "." for the root, "app/main.py" for files, "app/" for subdirectories. '
+            "Never pass absolute paths or the workspace root path itself.\n\n"
             "Available tools: " + ", ".join(tool_names) + "\n\n"
             "When you have fully completed the user's request, call the `finish` tool "
             "with a brief summary. If you can answer directly without tools, just respond "

app/utils/file_helpers.py

@@ -18,6 +18,9 @@ class BinaryFileError(Exception):
 def resolve_safe_path(path: str | Path, workspace_root: Path) -> Path:
     """Resolve a path and verify it is within the workspace root.
 
+    Handles absolute paths that point within the workspace (e.g. the LLM
+    passing the full workspace path) and relative paths alike.
+
     Args:
         path: The path to resolve (absolute or relative to workspace_root).
         workspace_root: The allowed root directory (must be absolute).
@@ -29,7 +32,22 @@ def resolve_safe_path(path: str | Path, workspace_root: Path) -> Path:
         PathSecurityError: If the resolved path is outside workspace_root.
     """
     workspace_root = workspace_root.resolve()
-    resolved = (workspace_root / path).resolve()
+    path = Path(path)
+
+    # If the path is absolute and within the workspace, use it directly.
+    # If absolute but outside, it will fail the security check below.
+    if path.is_absolute():
+        resolved = path.resolve()
+    else:
+        # Strip workspace_root prefix if the LLM included it as a relative path
+        # e.g. "home/user/project/foo.py" when workspace is "/home/user/project"
+        path_str = str(path)
+        ws_str = str(workspace_root).lstrip("/")
+        if path_str.startswith(ws_str + "/"):
+            path_str = path_str[len(ws_str) + 1:]
+        elif path_str == ws_str:
+            path_str = "."
+        resolved = (workspace_root / path_str).resolve()
 
     if not resolved.is_relative_to(workspace_root):
         raise PathSecurityError(