fix(tool-hint): fold paths in exec commands instead of blind truncation

exec tool hints previously used val[:40] which cut paths mid-segment
(e.g. "D:\Documents\GitHub\nanobot.worktree…"). Now uses regex to
detect file paths in commands and abbreviates them properly, with
smart truncation at chain separators (&&, |, ;) as fallback.

nanobot/utils/tool_hints.py

@@ -2,6 +2,8 @@
 
 from __future__ import annotations
 
+import re
+
 from nanobot.utils.path import abbreviate_path
 
 # Registry: tool_name -> (key_args, template, is_path, is_command)
@@ -17,6 +19,11 @@ _TOOL_FORMATS: dict[str, tuple[list[str], str, bool, bool]] = {
     "list_dir":   (["path"],                           "ls {}",       True,  False),
 }
 
+# Matches file paths embedded in shell commands (Windows drive, ~/, or absolute after space)
+_PATH_IN_CMD_RE = re.compile(
+    r"(?:[A-Za-z]:[/\\]|~/|(?<=\s)/)[^\s;&|<>\"']+"
+)
+
 
 def format_tool_hints(tool_calls: list) -> str:
     """Format tool calls as concise hints with smart abbreviation."""
@@ -85,10 +92,20 @@ def _fmt_known(tc, fmt: tuple) -> str:
     if fmt[2]:  # is_path
         val = abbreviate_path(val)
     elif fmt[3]:  # is_command
-        val = val[:40] + "\u2026" if len(val) > 40 else val
+        val = _abbreviate_command(val)
     return fmt[1].format(val)
 
 
+def _abbreviate_command(cmd: str, max_len: int = 40) -> str:
+    """Abbreviate paths in a command string, then truncate."""
+    abbreviated = _PATH_IN_CMD_RE.sub(
+        lambda m: abbreviate_path(m.group(), max_len=25), cmd
+    )
+    if len(abbreviated) <= max_len:
+        return abbreviated
+    return abbreviated[:max_len - 1] + "\u2026"
+
+
 def _fmt_mcp(tc) -> str:
     """Format MCP tool as server::tool."""
     name = tc.name

tests/agent/test_tool_hint.py

@@ -52,6 +52,37 @@ class TestToolHintKnownTools:
         assert result.startswith("$ ")
         assert len(result) <= 50  # reasonable limit
 
+    def test_exec_abbreviates_paths_in_command(self):
+        """Windows paths in exec commands should be folded, not blindly truncated."""
+        cmd = "cd D:\\Documents\\GitHub\\nanobot\\.worktree\\tomain\\nanobot && git diff origin/main...pr-2706 --name-only 2>&1"
+        result = _hint([_tc("exec", {"command": cmd})])
+        assert "\u2026/" in result  # path should be folded with …/
+        assert "worktree" not in result  # middle segments should be collapsed
+
+    def test_exec_abbreviates_linux_paths(self):
+        """Unix absolute paths in exec commands should be folded."""
+        cmd = "cd /home/user/projects/nanobot/.worktree/tomain && make build"
+        result = _hint([_tc("exec", {"command": cmd})])
+        assert "\u2026/" in result
+        assert "projects" not in result
+
+    def test_exec_abbreviates_home_paths(self):
+        """~/ paths in exec commands should be folded."""
+        cmd = "cd ~/projects/nanobot/workspace && pytest tests/"
+        result = _hint([_tc("exec", {"command": cmd})])
+        assert "\u2026/" in result
+
+    def test_exec_short_command_unchanged(self):
+        result = _hint([_tc("exec", {"command": "npm install typescript"})])
+        assert result == "$ npm install typescript"
+
+    def test_exec_chained_commands_truncated_not_mid_path(self):
+        """Long chained commands should truncate preserving abbreviated paths."""
+        cmd = "cd D:\\Documents\\GitHub\\project && npm run build && npm test"
+        result = _hint([_tc("exec", {"command": cmd})])
+        assert "\u2026/" in result  # path folded
+        assert "npm" in result  # chained command still visible
+
     def test_web_search(self):
         result = _hint([_tc("web_search", {"query": "Claude 4 vs GPT-4"})])
         assert result == 'search "Claude 4 vs GPT-4"'