feat: show estimated tool token context in hermes tools checklist (#3805)

* feat: show estimated tool token context in hermes tools checklist

Adds a live token estimate indicator to the bottom of the interactive
tool configuration checklist (hermes tools / hermes setup). As users
toggle toolsets on/off, the total estimated context cost updates in
real time.

Implementation:
- tools/registry.py: Add get_schema() for check_fn-free schema access
- hermes_cli/curses_ui.py: Add optional status_fn callback to
  curses_checklist — renders at bottom-right of terminal, stays fixed
  while items scroll
- hermes_cli/tools_config.py: Add _estimate_tool_tokens() using
  tiktoken (cl100k_base, already installed) to count tokens in the
  JSON-serialised OpenAI-format tool schemas. Results are cached
  per-process. The status function deduplicates overlapping tools
  (e.g. browser includes web_search) for accurate totals.
- 12 new tests covering estimation, caching, graceful degradation
  when tiktoken is unavailable, status_fn wiring, deduplication,
  and the numbered fallback display

* fix: use effective toolsets (includes plugins) for token estimation index mapping

The status_fn closure built ts_keys from CONFIGURABLE_TOOLSETS but the
checklist uses _get_effective_configurable_toolsets() which appends plugin
toolsets. With plugins present, the indices would mismatch, causing
IndexError when selecting a plugin toolset.

hermes_cli/curses_ui.py

@@ -4,7 +4,7 @@ Used by `hermes tools` and `hermes skills` for interactive checklists.
 Provides a curses multi-select with keyboard navigation, plus a
 text-based numbered fallback for terminals without curses support.
 """
-from typing import List, Set
+from typing import Callable, List, Optional, Set
 
 from hermes_cli.colors import Colors, color
 
@@ -15,6 +15,7 @@ def curses_checklist(
     selected: Set[int],
     *,
     cancel_returns: Set[int] | None = None,
+    status_fn: Optional[Callable[[Set[int]], str]] = None,
 ) -> Set[int]:
     """Curses multi-select checklist. Returns set of selected indices.
 
@@ -23,6 +24,9 @@ def curses_checklist(
         items: Display labels for each row.
         selected: Indices that start checked (pre-selected).
         cancel_returns: Returned on ESC/q. Defaults to the original *selected*.
+        status_fn: Optional callback ``f(chosen_indices) -> str`` whose return
+            value is rendered on the bottom row of the terminal.  Use this for
+            live aggregate info (e.g. estimated token counts).
     """
     if cancel_returns is None:
         cancel_returns = set(selected)
@@ -47,6 +51,9 @@ def curses_checklist(
                 stdscr.clear()
                 max_y, max_x = stdscr.getmaxyx()
 
+                # Reserve bottom row for status bar when status_fn provided
+                footer_rows = 1 if status_fn else 0
+
                 # Header
                 try:
                     hattr = curses.A_BOLD
@@ -62,7 +69,7 @@ def curses_checklist(
                     pass
 
                 # Scrollable item list
-                visible_rows = max_y - 3
+                visible_rows = max_y - 3 - footer_rows
                 if cursor < scroll_offset:
                     scroll_offset = cursor
                 elif cursor >= scroll_offset + visible_rows:
@@ -72,7 +79,7 @@ def curses_checklist(
                     range(scroll_offset, min(len(items), scroll_offset + visible_rows))
                 ):
                     y = draw_i + 3
-                    if y >= max_y - 1:
+                    if y >= max_y - 1 - footer_rows:
                         break
                     check = "✓" if i in chosen else " "
                     arrow = "→" if i == cursor else " "
@@ -87,6 +94,20 @@ def curses_checklist(
                     except curses.error:
                         pass
 
+                # Status bar (bottom row, right-aligned)
+                if status_fn:
+                    try:
+                        status_text = status_fn(chosen)
+                        if status_text:
+                            # Right-align on the bottom row
+                            sx = max(0, max_x - len(status_text) - 1)
+                            sattr = curses.A_DIM
+                            if curses.has_colors():
+                                sattr |= curses.color_pair(3)
+                            stdscr.addnstr(max_y - 1, sx, status_text, max_x - sx - 1, sattr)
+                    except curses.error:
+                        pass
+
                 stdscr.refresh()
                 key = stdscr.getch()
 
@@ -107,7 +128,7 @@ def curses_checklist(
         return result_holder[0] if result_holder[0] is not None else cancel_returns
 
     except Exception:
-        return _numbered_fallback(title, items, selected, cancel_returns)
+        return _numbered_fallback(title, items, selected, cancel_returns, status_fn)
 
 
 def _numbered_fallback(
@@ -115,6 +136,7 @@ def _numbered_fallback(
     items: List[str],
     selected: Set[int],
     cancel_returns: Set[int],
+    status_fn: Optional[Callable[[Set[int]], str]] = None,
 ) -> Set[int]:
     """Text-based toggle fallback for terminals without curses."""
     chosen = set(selected)
@@ -125,6 +147,10 @@ def _numbered_fallback(
         for i, label in enumerate(items):
             marker = color("[✓]", Colors.GREEN) if i in chosen else "[ ]"
             print(f"  {marker} {i + 1:>2}. {label}")
+        if status_fn:
+            status_text = status_fn(chosen)
+            if status_text:
+                print(color(f"\n  {status_text}", Colors.DIM))
         print()
         try:
             val = input(color("  Toggle # (or Enter to confirm): ", Colors.DIM)).strip()

hermes_cli/tools_config.py

@@ -9,6 +9,8 @@ Saves per-platform tool configuration to ~/.hermes/config.yaml under
 the `platform_toolsets` key.
 """
 
+import json as _json
+import logging
 import sys
 from pathlib import Path
 from typing import Dict, List, Optional, Set
@@ -19,6 +21,8 @@ from hermes_cli.config import (
 )
 from hermes_cli.colors import Colors, color
 
+logger = logging.getLogger(__name__)
+
 PROJECT_ROOT = Path(__file__).parent.parent.resolve()
 
 
@@ -653,9 +657,61 @@ def _prompt_choice(question: str, choices: list, default: int = 0) -> int:
             return default
 
 
+# ─── Token Estimation ────────────────────────────────────────────────────────
+
+# Module-level cache so discovery + tokenization runs at most once per process.
+_tool_token_cache: Optional[Dict[str, int]] = None
+
+
+def _estimate_tool_tokens() -> Dict[str, int]:
+    """Return estimated token counts per individual tool name.
+
+    Uses tiktoken (cl100k_base) to count tokens in the JSON-serialised
+    OpenAI-format tool schema.  Triggers tool discovery on first call,
+    then caches the result for the rest of the process.
+
+    Returns an empty dict when tiktoken or the registry is unavailable.
+    """
+    global _tool_token_cache
+    if _tool_token_cache is not None:
+        return _tool_token_cache
+
+    try:
+        import tiktoken
+        enc = tiktoken.get_encoding("cl100k_base")
+    except Exception:
+        logger.debug("tiktoken unavailable; skipping tool token estimation")
+        _tool_token_cache = {}
+        return _tool_token_cache
+
+    try:
+        # Trigger full tool discovery (imports all tool modules).
+        import model_tools  # noqa: F401
+        from tools.registry import registry
+    except Exception:
+        logger.debug("Tool registry unavailable; skipping token estimation")
+        _tool_token_cache = {}
+        return _tool_token_cache
+
+    counts: Dict[str, int] = {}
+    for name in registry.get_all_tool_names():
+        schema = registry.get_schema(name)
+        if schema:
+            # Mirror what gets sent to the API:
+            # {"type": "function", "function": <schema>}
+            text = _json.dumps({"type": "function", "function": schema})
+            counts[name] = len(enc.encode(text))
+    _tool_token_cache = counts
+    return _tool_token_cache
+
+
 def _prompt_toolset_checklist(platform_label: str, enabled: Set[str]) -> Set[str]:
     """Multi-select checklist of toolsets. Returns set of selected toolset keys."""
     from hermes_cli.curses_ui import curses_checklist
+    from toolsets import resolve_toolset
+
+    # Pre-compute per-tool token counts (cached after first call).
+    tool_tokens = _estimate_tool_tokens()
 
     effective = _get_effective_configurable_toolsets()
 
@@ -671,11 +727,27 @@ def _prompt_toolset_checklist(platform_label: str, enabled: Set[str]) -> Set[str
         if ts_key in enabled
     }
 
+    # Build a live status function that shows deduplicated total token cost.
+    status_fn = None
+    if tool_tokens:
+        ts_keys = [ts_key for ts_key, _, _ in effective]
+
+        def status_fn(chosen: set) -> str:
+            # Collect unique tool names across all selected toolsets
+            all_tools: set = set()
+            for idx in chosen:
+                all_tools.update(resolve_toolset(ts_keys[idx]))
+            total = sum(tool_tokens.get(name, 0) for name in all_tools)
+            if total >= 1000:
+                return f"Est. tool context: ~{total / 1000:.1f}k tokens"
+            return f"Est. tool context: ~{total} tokens"
+
     chosen = curses_checklist(
         f"Tools for {platform_label}",
         labels,
         pre_selected,
         cancel_returns=pre_selected,
+        status_fn=status_fn,
     )
     return {effective[i][0] for i in chosen}
 

tests/hermes_cli/test_tool_token_estimation.py

@@ -0,0 +1,271 @@
+"""Tests for tool token estimation and curses_ui status_fn support."""
+
+from unittest.mock import patch
+
+import pytest
+
+
+# ─── Token Estimation Tests ──────────────────────────────────────────────────
+
+
+def test_estimate_tool_tokens_returns_positive_counts():
+    """_estimate_tool_tokens should return a non-empty dict with positive values."""
+    from hermes_cli.tools_config import _estimate_tool_tokens, _tool_token_cache
+
+    # Clear cache to force fresh computation
+    import hermes_cli.tools_config as tc
+    tc._tool_token_cache = None
+
+    tokens = _estimate_tool_tokens()
+
+    assert isinstance(tokens, dict)
+    assert len(tokens) > 0
+    for name, count in tokens.items():
+        assert isinstance(name, str)
+        assert isinstance(count, int)
+        assert count > 0, f"Tool {name} has non-positive token count: {count}"
+
+
+def test_estimate_tool_tokens_is_cached():
+    """Second call should return the same cached dict object."""
+    import hermes_cli.tools_config as tc
+    tc._tool_token_cache = None
+
+    first = tc._estimate_tool_tokens()
+    second = tc._estimate_tool_tokens()
+
+    assert first is second
+
+
+def test_estimate_tool_tokens_returns_empty_when_tiktoken_unavailable(monkeypatch):
+    """Graceful degradation when tiktoken cannot be imported."""
+    import hermes_cli.tools_config as tc
+    tc._tool_token_cache = None
+
+    import builtins
+    real_import = builtins.__import__
+
+    def mock_import(name, *args, **kwargs):
+        if name == "tiktoken":
+            raise ImportError("mocked")
+        return real_import(name, *args, **kwargs)
+
+    monkeypatch.setattr(builtins, "__import__", mock_import)
+
+    result = tc._estimate_tool_tokens()
+
+    assert result == {}
+
+    # Reset cache for other tests
+    tc._tool_token_cache = None
+
+
+def test_estimate_tool_tokens_covers_known_tools():
+    """Should include schemas for well-known tools like terminal, web_search."""
+    import hermes_cli.tools_config as tc
+    tc._tool_token_cache = None
+
+    tokens = tc._estimate_tool_tokens()
+
+    # These tools should always be discoverable
+    for expected in ("terminal", "web_search", "read_file"):
+        assert expected in tokens, f"Expected {expected!r} in token estimates"
+
+
+# ─── Status Function Tests ───────────────────────────────────────────────────
+
+
+def test_prompt_toolset_checklist_passes_status_fn(monkeypatch):
+    """_prompt_toolset_checklist should pass a status_fn to curses_checklist."""
+    import hermes_cli.tools_config as tc
+
+    captured_kwargs = {}
+
+    def fake_checklist(title, items, selected, *, cancel_returns=None, status_fn=None):
+        captured_kwargs["status_fn"] = status_fn
+        captured_kwargs["title"] = title
+        return selected  # Return pre-selected unchanged
+
+    monkeypatch.setattr("hermes_cli.curses_ui.curses_checklist", fake_checklist)
+
+    tc._prompt_toolset_checklist("CLI", {"web", "terminal"})
+
+    assert "status_fn" in captured_kwargs
+    # If tiktoken is available, status_fn should be set
+    tokens = tc._estimate_tool_tokens()
+    if tokens:
+        assert captured_kwargs["status_fn"] is not None
+
+
+def test_status_fn_returns_formatted_token_count(monkeypatch):
+    """The status_fn should return a human-readable token count string."""
+    import hermes_cli.tools_config as tc
+    from hermes_cli.tools_config import CONFIGURABLE_TOOLSETS
+
+    captured = {}
+
+    def fake_checklist(title, items, selected, *, cancel_returns=None, status_fn=None):
+        captured["status_fn"] = status_fn
+        return selected
+
+    monkeypatch.setattr("hermes_cli.curses_ui.curses_checklist", fake_checklist)
+
+    tc._prompt_toolset_checklist("CLI", {"web", "terminal"})
+
+    status_fn = captured.get("status_fn")
+    if status_fn is None:
+        pytest.skip("tiktoken unavailable; status_fn not created")
+
+    # Find the indices for web and terminal
+    idx_map = {ts_key: i for i, (ts_key, _, _) in enumerate(CONFIGURABLE_TOOLSETS)}
+
+    # Call status_fn with web + terminal selected
+    result = status_fn({idx_map["web"], idx_map["terminal"]})
+    assert "tokens" in result
+    assert "Est. tool context" in result
+
+
+def test_status_fn_deduplicates_overlapping_tools(monkeypatch):
+    """When toolsets overlap (browser includes web_search), tokens should not double-count."""
+    import hermes_cli.tools_config as tc
+    from hermes_cli.tools_config import CONFIGURABLE_TOOLSETS
+
+    captured = {}
+
+    def fake_checklist(title, items, selected, *, cancel_returns=None, status_fn=None):
+        captured["status_fn"] = status_fn
+        return selected
+
+    monkeypatch.setattr("hermes_cli.curses_ui.curses_checklist", fake_checklist)
+
+    tc._prompt_toolset_checklist("CLI", {"web"})
+
+    status_fn = captured.get("status_fn")
+    if status_fn is None:
+        pytest.skip("tiktoken unavailable; status_fn not created")
+
+    idx_map = {ts_key: i for i, (ts_key, _, _) in enumerate(CONFIGURABLE_TOOLSETS)}
+
+    # web alone
+    web_only = status_fn({idx_map["web"]})
+    # browser includes web_search, so browser + web should not double-count web_search
+    browser_only = status_fn({idx_map["browser"]})
+    both = status_fn({idx_map["web"], idx_map["browser"]})
+
+    # Extract numeric token counts from strings like "~8.3k tokens" or "~350 tokens"
+    import re
+
+    def parse_tokens(s):
+        m = re.search(r"~([\d.]+)k?\s+tokens", s)
+        if not m:
+            return 0
+        val = float(m.group(1))
+        if "k" in s[m.start():m.end()]:
+            val *= 1000
+        return val
+
+    web_tok = parse_tokens(web_only)
+    browser_tok = parse_tokens(browser_only)
+    both_tok = parse_tokens(both)
+
+    # Both together should be LESS than naive sum (due to web_search dedup)
+    naive_sum = web_tok + browser_tok
+    assert both_tok < naive_sum, (
+        f"Expected deduplication: web({web_tok}) + browser({browser_tok}) = {naive_sum} "
+        f"but combined = {both_tok}"
+    )
+
+
+def test_status_fn_empty_selection():
+    """Status function with no tools selected should return ~0 tokens."""
+    import hermes_cli.tools_config as tc
+
+    tc._tool_token_cache = None
+    tokens = tc._estimate_tool_tokens()
+    if not tokens:
+        pytest.skip("tiktoken unavailable")
+
+    from hermes_cli.tools_config import CONFIGURABLE_TOOLSETS
+    from toolsets import resolve_toolset
+
+    ts_keys = [ts_key for ts_key, _, _ in CONFIGURABLE_TOOLSETS]
+
+    def status_fn(chosen: set) -> str:
+        all_tools: set = set()
+        for idx in chosen:
+            all_tools.update(resolve_toolset(ts_keys[idx]))
+        total = sum(tokens.get(name, 0) for name in all_tools)
+        if total >= 1000:
+            return f"Est. tool context: ~{total / 1000:.1f}k tokens"
+        return f"Est. tool context: ~{total} tokens"
+
+    result = status_fn(set())
+    assert "~0 tokens" in result
+
+
+# ─── Curses UI Status Bar Tests ──────────────────────────────────────────────
+
+
+def test_curses_checklist_numbered_fallback_shows_status(monkeypatch, capsys):
+    """The numbered fallback should print the status_fn output."""
+    from hermes_cli.curses_ui import _numbered_fallback
+
+    def my_status(chosen):
+        return f"Selected {len(chosen)} items"
+
+    # Simulate user pressing Enter immediately (empty input → confirm)
+    monkeypatch.setattr("builtins.input", lambda _prompt="": "")
+
+    result = _numbered_fallback(
+        "Test title",
+        ["Item A", "Item B", "Item C"],
+        {0, 2},
+        {0, 2},
+        status_fn=my_status,
+    )
+
+    captured = capsys.readouterr()
+    assert "Selected 2 items" in captured.out
+    assert result == {0, 2}
+
+
+def test_curses_checklist_numbered_fallback_without_status(monkeypatch, capsys):
+    """The numbered fallback should work fine without status_fn."""
+    from hermes_cli.curses_ui import _numbered_fallback
+
+    monkeypatch.setattr("builtins.input", lambda _prompt="": "")
+
+    result = _numbered_fallback(
+        "Test title",
+        ["Item A", "Item B"],
+        {0},
+        {0},
+    )
+
+    captured = capsys.readouterr()
+    assert "Est. tool context" not in captured.out
+    assert result == {0}
+
+
+# ─── Registry get_schema Tests ───────────────────────────────────────────────
+
+
+def test_registry_get_schema_returns_schema():
+    """registry.get_schema() should return a tool's schema dict."""
+    from tools.registry import registry
+
+    # Import to trigger discovery
+    import model_tools  # noqa: F401
+
+    schema = registry.get_schema("terminal")
+    assert schema is not None
+    assert "name" in schema
+    assert schema["name"] == "terminal"
+    assert "parameters" in schema
+
+
+def test_registry_get_schema_returns_none_for_unknown():
+    """registry.get_schema() should return None for unknown tools."""
+    from tools.registry import registry
+
+    assert registry.get_schema("nonexistent_tool_xyz") is None

tools/registry.py

@@ -149,6 +149,15 @@ class ToolRegistry:
         """Return sorted list of all registered tool names."""
         return sorted(self._tools.keys())
 
+    def get_schema(self, name: str) -> Optional[dict]:
+        """Return a tool's raw schema dict, bypassing check_fn filtering.
+
+        Useful for token estimation and introspection where availability
+        doesn't matter — only the schema content does.
+        """
+        entry = self._tools.get(name)
+        return entry.schema if entry else None
+
     def get_toolset_for_tool(self, name: str) -> Optional[str]:
         """Return the toolset a tool belongs to, or None."""
         entry = self._tools.get(name)