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hermes-agent/tools/tool_search.py
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27 KiB
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"""Progressive tool disclosure ("tool search"): MCP/plugin tools and a curated set
of event-triggered core tools are replaced in the model-visible array by three
bridge tools — tool_search / tool_describe / tool_call.
Invariants: working-set core tools (``toolsets._HERMES_CORE_TOOLS``) and
session-gated GUI toolsets never defer unless named in ``defer``; ANY deferrable
tool activates the bridge (the listing scales with budget, not activation); the
catalog is stateless — rebuilt from the live tool-defs on every assembly (a
session-keyed catalog drifts from the registry and silently drops tools); bridge
calls route through ``model_tools.handle_function_call`` so guardrails, hooks,
approvals and truncation fire identically.
"""
from __future__ import annotations
import json
import logging
import math
from collections import Counter
from dataclasses import dataclass
from typing import Any, Dict, Iterable, List, Optional, Tuple
from tools.registry import tool_error
from tools.tool_search_names import ( # noqa: F401 — re-exported public names
BRIDGE_TOOL_NAMES, TOOL_CALL_NAME, TOOL_DESCRIBE_NAME, TOOL_SEARCH_NAME,
)
from tools.tool_search_catalog import ( # noqa: F401 — re-exported public/test names
CHARS_PER_TOKEN, CatalogEntry, _corpus_stats, _entry_search_text, _fn,
_listing_group_label, _registry_entry, _short_desc, _stem, _tokenize,
build_catalog, build_catalog_listing_with_form, search_catalog,
)
from tools.tool_search_validation import validate_deferred_call_args # noqa: F401
logger = logging.getLogger("tools.tool_search")
# Bound the work one bridge call can request.
_MAX_QUERIES_PER_CALL = 10
_MAX_DESCRIBE_NAMES_PER_CALL = 10
@dataclass(frozen=True)
class ToolSearchConfig:
"""Resolved, validated tool-search configuration for a single assembly."""
enabled: str # "auto" | "on" | "off" — "auto" is an alias of "on" today
# Listing budget as % of context. Does NOT gate activation; bounds how much
# the embedded listing may consume before it degrades (full -> names -> bare).
threshold_pct: float # 0..100
search_default_limit: int
max_search_limit: int
# Embedded name + short-description manifest keeping deferred tools
# DISCOVERABLE. "auto"/"on" = include when it fits; "off" = bare bridge.
listing: str = "auto" # "auto" | "on" | "off"
# Effective budget = min(listing_max_tokens, threshold_pct% of context).
listing_max_tokens: int = 4000
# Core/GUI names deferred behind the bridge. None = curated default; an
# explicit config list replaces it wholesale ([] = defer no core tools).
defer_tools: Optional[frozenset] = None
@property
def effective_defer_tools(self) -> frozenset:
return _DEFAULT_DEFERRED_TOOLS if self.defer_tools is None else self.defer_tools
@classmethod
def from_raw(cls, raw: Any) -> "ToolSearchConfig":
"""Build from a raw dict / legacy bool / None. Every field is clamped and
unknown values fall back to safe defaults — a config typo must not break the agent."""
if not isinstance(raw, dict):
return cls(enabled="off" if raw is False else "auto", threshold_pct=5.0,
search_default_limit=5, max_search_limit=25)
max_search_limit = _clamped_int(raw.get("max_search_limit"), 25, 1, 50)
defer_raw = raw.get("defer")
return cls(
enabled=_tri_state(raw.get("enabled", "auto")),
threshold_pct=max(0.0, min(100.0, _safe_float(raw.get("threshold_pct"), 5.0))),
search_default_limit=_clamped_int(
raw.get("search_default_limit"), 5, 1, max_search_limit),
max_search_limit=max_search_limit,
listing=_tri_state(raw.get("listing", "auto")),
listing_max_tokens=_clamped_int(raw.get("listing_max_tokens"), 4000, 200, 60000),
# A list replaces the curated default wholesale; anything else = curated.
defer_tools=(
frozenset(str(n).strip() for n in defer_raw if str(n).strip())
if isinstance(defer_raw, (list, tuple, set)) else None))
_TRI_STATE_ALIASES = {"true": "on", "1": "on", "yes": "on", "false": "off", "0": "off", "no": "off"}
def _tri_state(value: Any) -> str:
"""Normalize an ``auto``/``on``/``off`` setting (bool-ish aliases accepted)."""
text = str(value).strip().lower()
text = _TRI_STATE_ALIASES.get(text, text)
return text if text in ("auto", "on", "off") else "auto"
def _clamped_int(value: Any, fallback: int, lo: int, hi: int) -> int:
"""``int(value)`` (or ``fallback`` when unparseable) clamped to ``[lo, hi]``."""
try:
value = int(value)
except (TypeError, ValueError):
value = fallback
return max(lo, min(hi, value))
def _safe_float(value: Any, fallback: float) -> float:
try:
return float(value)
except (TypeError, ValueError):
return fallback
def _config_from_loader(loader_name: str) -> ToolSearchConfig:
try:
import hermes_cli.config as _cfg_mod
cfg = getattr(_cfg_mod, loader_name)() or {}
tools_cfg = cfg.get("tools") if isinstance(cfg.get("tools"), dict) else {}
return ToolSearchConfig.from_raw(tools_cfg.get("tool_search"))
except Exception as e:
logger.debug("Failed to load tool-search config: %s", e)
return ToolSearchConfig.from_raw(None)
def load_config() -> ToolSearchConfig:
"""Load tool-search config from the user config file."""
return _config_from_loader("load_config")
def load_config_readonly() -> ToolSearchConfig:
"""Load tool-search config without copying the cached full config."""
return _config_from_loader("load_config_readonly")
def _core_tool_names() -> frozenset[str]:
"""Tool names that never defer by default (lazy import: ``toolsets`` imports
``tools.registry``, so a module-level import would be a cycle)."""
try:
from toolsets import _HERMES_CORE_TOOLS
return frozenset(_HERMES_CORE_TOOLS)
except Exception:
return frozenset()
# Session-gated GUI toolsets: off ``_HERMES_CORE_TOOLS`` so non-GUI clients never
# pay their schema; once enabled they stay direct unless the deferral list names them.
_DIRECT_SURFACE_TOOLSETS = frozenset({"desktop_ui", "project"})
# Curated event-triggered core tools deferred BY DEFAULT — reached for when
# something specific happens, so a catalog stub suffices. ``tools.tool_search.defer``
# replaces this list wholesale ([] = legacy everything-eager). Names are POST-rename.
# ``clarify`` is deliberately NOT here: A/B showed deferring it collapsed
# structured-clarify usage (18/18 -> 7/18) — the ask-the-user affordance must
# be ambient to fire; a stub is not enough.
_DEFAULT_DEFERRED_TOOLS = frozenset({
"computer_use", "session_search", "image_generate",
"todo_list", "process_manage", "cronjob_manage",
# Desktop GUI surface (desktop_ui + project toolsets)
"drive_preview", "gui_tour", "desktop_preview", "annotate_preview",
"show_tip", "setup_mcp", "desktop_project", "close_terminal",
"apply_layout", "read_terminal", "read_window_below", "focus_pane",
})
def is_deferrable_tool_name(name: str, defer_tools: Optional[frozenset] = None) -> bool:
"""True if a tool is *eligible* for deferral: named in ``defer_tools``
(curated core set or user override), OR an MCP tool, OR neither core nor a
session-gated GUI surface (i.e. a plugin tool). Bridge names never defer."""
if name in BRIDGE_TOOL_NAMES:
return False
if defer_tools is not None and name in defer_tools:
return True
if name in _core_tool_names():
return False
entry = _registry_entry(name)
if entry is None:
return False
try:
return entry.toolset.startswith("mcp-") or entry.toolset not in _DIRECT_SURFACE_TOOLSETS
except Exception: # malformed entry (no str toolset) is never deferrable
return False
def _tool_def_names(tool_defs: Iterable[Dict[str, Any]]) -> Iterable[str]:
"""Function names of a tool-defs list (``""`` for a nameless def)."""
return (_fn(td).get("name", "") for td in tool_defs)
def classify_tools(
tool_defs: List[Dict[str, Any]],
defer_tools: Optional[frozenset] = None) -> Tuple[List[Dict[str, Any]], List[Dict[str, Any]]]:
"""Split a tool-defs list into (visible, deferrable). Bridge tools are
dropped (they are re-added after classification)."""
visible: List[Dict[str, Any]] = []
deferrable: List[Dict[str, Any]] = []
for td, name in zip(tool_defs, _tool_def_names(tool_defs)):
if name in BRIDGE_TOOL_NAMES:
continue
(deferrable if is_deferrable_tool_name(name, defer_tools) else visible).append(td)
return visible, deferrable
def _deferrable_in(tool_defs: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
"""Deferrable subset of a pre-assembly ``tool_defs`` list under the current
(read-only) user config — the universe the bridge tools operate on."""
return classify_tools(tool_defs, load_config_readonly().effective_defer_tools)[1]
def estimate_tokens_from_schemas(tool_defs: Iterable[Dict[str, Any]]) -> int:
"""Token cost of a tool-defs list via the chars/4 rule (order-of-magnitude
precision is all the activation gate needs)."""
total_chars = 0
for td in tool_defs:
try:
total_chars += len(json.dumps(td, ensure_ascii=False, separators=(",", ":")))
except (TypeError, ValueError):
total_chars += len(str(td))
return int(math.ceil(total_chars / CHARS_PER_TOKEN))
def should_activate(
config: ToolSearchConfig,
deferrable_tokens: int,
context_length: Optional[int]) -> bool:
"""``"off"`` never activates; ``"on"``/``"auto"`` activate whenever any
deferrable tool exists. ``"auto"`` is an alias of ``"on"`` reserved for a
future budget-gated mode — do not distinguish them without that design.
``context_length`` stays in the signature for caller compatibility; the
threshold governs the listing budget, not activation."""
return config.enabled != "off" and deferrable_tokens > 0
def listing_token_budget(config: ToolSearchConfig, context_length: Optional[int]) -> int:
"""``min(listing_max_tokens, threshold_pct% of context)``; unknown context
uses a 10K percentage leg (5% of a typical 200K window)."""
if context_length and context_length > 0:
pct_leg = int(context_length * (config.threshold_pct / 100.0))
else:
pct_leg = 10_000
return max(0, min(config.listing_max_tokens, pct_leg))
def _bridge_schema(name: str, description: str, properties: Dict[str, Any],
required: List[str]) -> Dict[str, Any]:
"""One OpenAI-style function schema (key order is part of the frozen bytes)."""
return {
"type": "function",
"function": {
"name": name,
"description": description,
"parameters": {"type": "object", "properties": properties, "required": required},
},
}
def _search_description(deferred_count: int, listing: Optional[str], listing_form: str) -> str:
"""tool_search bridge description with the listing embedded; ``listing_form``
picks the framing (see :func:`bridge_tool_schemas`)."""
desc = (
f"Search {deferred_count} additional tools that are loaded on demand. "
"Takes a list of queries searched in parallel against the same "
"catalog; send one query per distinct capability you need. Returns "
"matching tool names grouped per query plus a shared map with each "
"tool's description. Follow with "
f"`{TOOL_DESCRIBE_NAME}` to load full parameter schemas, "
f"then `{TOOL_CALL_NAME}` to invoke. Tools listed at the top of this "
"system prompt are already available and do not need to be searched.")
if not listing:
return desc
if listing_form == "groups":
return desc + (
"\n\nThe servers below are connected and their tools ARE available "
"through this bridge. For any request in these domains, search "
"here FIRST — do not claim the capability is unavailable and do "
"not substitute a generic tool (terminal/browser) without "
"searching.\n\n" + listing)
desc += (
"\n\nEvery deferred capability is listed below. If a tool name "
"appears here, do NOT claim it is unavailable — load it with "
f"`{TOOL_DESCRIBE_NAME}` (skip `{TOOL_SEARCH_NAME}` when you "
"already see the exact name).")
if listing_form == "mixed":
desc += (
" For servers marked 'names not listed', the tools exist "
f"too — find them with `{TOOL_SEARCH_NAME}` before "
"concluding anything is missing.")
return desc + "\n\n" + listing
def bridge_tool_schemas(
deferred_count: int,
listing: Optional[str] = None,
listing_form: str = "") -> List[Dict[str, Any]]:
"""Bridge tool schemas injected in place of deferred tools. Kept short —
every byte is paid on every turn. ``listing`` is embedded in the tool_search
description; ``listing_form`` picks the framing (per-tool forms say "skip
search when you see the exact name", "groups" says which domains exist and
that search is mandatory)."""
return [
_bridge_schema(
TOOL_SEARCH_NAME,
_search_description(deferred_count, listing, listing_form),
{
"queries": {
"type": "array",
"items": {"type": "string"},
"description": "Search queries, each a few keywords describing one capability (e.g. ['create github issue', 'send slack message']). Searched in parallel; results come back grouped per query. A single string is accepted and treated as one query.",
},
"limit": {
"type": "integer",
"description": "Maximum number of matches per query. Defaults to 5 and is clamped to the configured maximum (25 by default).",
},
},
["queries"],
),
_bridge_schema(
TOOL_DESCRIBE_NAME,
f"Load the full JSON schemas for tools returned by `{TOOL_SEARCH_NAME}`. "
f"Required before `{TOOL_CALL_NAME}` if a tool's parameters are unknown. "
"Batch every schema you need into one call.",
{
"names": {
"type": "array",
"items": {"type": "string"},
"description": "Exact tool names (as returned by tool_search). A single string is accepted and treated as one name.",
},
},
["names"],
),
_bridge_schema(
TOOL_CALL_NAME,
"Invoke a deferred tool by name with the given arguments. Argument shape "
f"matches the tool's schema (see `{TOOL_DESCRIBE_NAME}`). Policy, hooks, "
"and approvals run exactly as for any directly-listed tool.",
{
"name": {"type": "string", "description": "Exact tool name to invoke."},
"arguments": {
"type": "object",
"description": "Arguments for the tool, matching its schema.",
},
},
["name", "arguments"],
),
]
@dataclass
class AssemblyResult:
"""Outcome of one assembly (tests and observability)."""
tool_defs: List[Dict[str, Any]]
activated: bool
deferred_count: int = 0
deferred_tokens: int = 0
threshold_tokens: int = 0
# 0 = passthrough; 1 = bridge + per-tool listing (full/names/mixed);
# 2 = bare bridge / server-summary only (tools reachable only via tool_search).
tier: int = 0
listing_form: str = "none" # "full" | "names" | "mixed" | "groups" | "none"
def assemble_tool_defs(
tool_defs: List[Dict[str, Any]],
*,
context_length: Optional[int] = None,
config: Optional[ToolSearchConfig] = None) -> AssemblyResult:
"""Return the tool-defs list the model should actually see: passthrough
when inactive, otherwise deferrable tools replaced by the three bridge
tools. Idempotent — bridge tools already present are stripped first."""
if config is None:
config = load_config()
incoming = [td for td, name in zip(tool_defs, _tool_def_names(tool_defs))
if name not in BRIDGE_TOOL_NAMES]
visible, deferrable = classify_tools(incoming, config.effective_defer_tools)
if not deferrable:
return AssemblyResult(tool_defs=incoming, activated=False)
deferrable_tokens = estimate_tokens_from_schemas(deferrable)
if not should_activate(config, deferrable_tokens, context_length):
return AssemblyResult(
tool_defs=incoming, activated=False, deferred_count=len(deferrable),
deferred_tokens=deferrable_tokens,
threshold_tokens=int((context_length or 0) * (config.threshold_pct / 100.0)),
tier=0)
listing, listing_form = None, "none"
listing_budget = listing_token_budget(config, context_length)
if config.listing != "off":
listing, listing_form = build_catalog_listing_with_form(
deferrable, max_tokens=listing_budget)
bridge = bridge_tool_schemas(len(deferrable), listing=listing, listing_form=listing_form)
tier = 1 if listing_form in ("full", "names", "mixed") else 2
logger.info(
"tool_search activated (tier %d): %d core/visible tools kept, %d deferred "
"(~%d tokens), listing %s (budget ~%d tokens)",
tier, len(visible), len(deferrable), deferrable_tokens, listing_form, listing_budget)
return AssemblyResult(
tool_defs=visible + bridge, activated=True, deferred_count=len(deferrable),
deferred_tokens=deferrable_tokens, threshold_tokens=listing_budget,
tier=tier, listing_form=listing_form)
def is_bridge_tool(name: str) -> bool:
return name in BRIDGE_TOOL_NAMES
def _shared_tool_record(entry: CatalogEntry) -> Dict[str, Any]:
"""One record for the response's shared ``tools`` map (held once per tool;
per-query groups carry names only). ``required`` lets the model attempt a
trivial call without a ``tool_describe`` round-trip."""
schema = entry.schema if isinstance(entry.schema, dict) else {}
fn = schema.get("function")
params = fn.get("parameters") if isinstance(fn, dict) else None
required = params.get("required") if isinstance(params, dict) else None
if not isinstance(required, list):
required = []
return {
"source": entry.source,
"source_name": entry.source_name,
"description": (entry.description or "")[:400], # cap chatty MCP descriptions
"required": [r[:64] for r in required if isinstance(r, str)][:32]}
def _available_source_summary(catalog: List[CatalogEntry]) -> List[Dict[str, Any]]:
"""Deterministic ``[{name, tool_count}]`` of connected sources, attached to
empty query groups so a lexical miss is not read as a missing capability."""
counts = Counter(_listing_group_label(entry.source_name) for entry in catalog)
return [{"name": name, "tool_count": counts[name]} for name in sorted(counts)]
def _string_list_arg(
args: Dict[str, Any], key: str, *, dedupe: bool, max_items: int, retry_hint: str,
) -> Tuple[Optional[List[str]], Optional[str]]:
"""Read a list-of-strings bridge argument -> ``(items, error_json)``. A bare
string (a common model slip) counts as a one-item list. Rejects non-list
input, an empty list (after stripping blanks), and more than ``max_items``."""
raw = args.get(key)
if isinstance(raw, str):
raw = [raw]
if not isinstance(raw, list):
return None, tool_error(f"{key} is required and must be an array of strings")
out: List[str] = []
for item in raw:
text = str(item or "").strip()
if text and (not dedupe or text not in out):
out.append(text)
if not out:
return None, tool_error(
f"{key} is required and must contain at least one non-empty string")
if len(out) > max_items:
return None, tool_error(
f"too many {key}: {len(out)} > max {max_items}. {retry_hint}")
return out, None
def dispatch_tool_search(args: Dict[str, Any],
*,
current_tool_defs: List[Dict[str, Any]],
config: Optional[ToolSearchConfig] = None) -> str:
"""Execute the ``tool_search`` bridge tool. Returns JSON::
{"queries": [...], "total_available": N,
"results": [{"query": ..., "matches": [names...]}, ...],
"tools": {name: {"source", "source_name", "description", "required"}}}
``limit`` applies PER QUERY. Empty query groups get ``available_sources`` +
``hint`` so a lexical miss is not mistaken for a missing capability.
"""
if config is None:
config = load_config()
queries, err = _string_list_arg(
args, "queries", dedupe=False, max_items=_MAX_QUERIES_PER_CALL,
retry_hint="Retry with fewer, more targeted queries.")
if err:
return err
raw_limit = args.get("limit")
limit = (config.search_default_limit if raw_limit is None
else _clamped_int(raw_limit, config.search_default_limit, 1, config.max_search_limit))
catalog = build_catalog(_deferrable_in(current_tool_defs))
results: List[Dict[str, Any]] = []
tools_map: Dict[str, Dict[str, Any]] = {}
corpus_stats = _corpus_stats(catalog)
available_sources = _available_source_summary(catalog) if catalog else []
for query in queries:
hits = search_catalog(catalog, query, limit=limit, corpus_stats=corpus_stats)
for h in hits:
tools_map.setdefault(h.name, _shared_tool_record(h))
group: Dict[str, Any] = {"query": query, "matches": [h.name for h in hits]}
if not hits and catalog:
group["available_sources"] = available_sources
group["hint"] = (
"This query returned no lexical matches, but the sources above "
"are connected and their tools remain available. Retry "
"tool_search with the service name plus a concrete action or "
"object before concluding the capability is unavailable.")
results.append(group)
return json.dumps({
"queries": queries,
"total_available": len(catalog),
"results": results,
"tools": tools_map,
}, ensure_ascii=False)
def dispatch_tool_describe(args: Dict[str, Any],
*,
current_tool_defs: List[Dict[str, Any]],
config: Optional[ToolSearchConfig] = None) -> str:
"""Execute the ``tool_describe`` bridge tool. Returns JSON::
{"tools": {name: {"description", "parameters"}},
"not_found": [...], # unknown / not in this assembly (never fails the call)
"errors": {name: msg}} # registered but non-deferrable names
Duplicates are deduped silently.
"""
if config is None:
config = load_config_readonly()
names, err = _string_list_arg(
args, "names", dedupe=True, max_items=_MAX_DESCRIBE_NAMES_PER_CALL,
retry_hint="Retry with fewer names per call.")
if err:
return err
deferrable = _deferrable_in(current_tool_defs)
by_name = {name: _fn(td) for td, name in zip(deferrable, _tool_def_names(deferrable)) if name}
tools: Dict[str, Dict[str, Any]] = {}
not_found: List[str] = []
errors: Dict[str, str] = {}
for name in names:
fn = by_name.get(name)
if fn is not None:
tools[name] = {
"description": fn.get("description", ""),
"parameters": fn.get("parameters", {})}
elif _registry_entry(name) is not None and not is_deferrable_tool_name(
name, load_config_readonly().effective_defer_tools):
# Registered but bridge/core/GUI-surface: a real name, wrong door.
errors[name] = (
f"'{name}' is not a deferrable tool. If you see it in the tools list "
"already, call it directly; otherwise check the spelling against tool_search.")
else:
not_found.append(name)
result: Dict[str, Any] = {"tools": tools}
if not_found:
result["not_found"] = not_found
result["hint"] = "Names in not_found are not currently available. Re-run tool_search to refresh."
if errors:
result["errors"] = errors
return json.dumps(result, ensure_ascii=False)
def scoped_deferrable_names(tool_defs: List[Dict[str, Any]]) -> frozenset[str]:
"""Deferrable tool names in the *pre-assembly* ``tool_defs`` of the session's
toolset scope — the universe ``tool_call`` may reach. Gates both bridge
dispatch and the executor unwrap so a restricted session cannot invoke an
out-of-scope tool via the bridge."""
defer_tools = load_config_readonly().effective_defer_tools
return frozenset(
name for name in _tool_def_names(tool_defs)
if name and is_deferrable_tool_name(name, defer_tools))
def resolve_underlying_call(args: Dict[str, Any]) -> Tuple[Optional[str], Dict[str, Any], Optional[str]]:
"""Parse a ``tool_call`` invocation into (underlying_name, args, error_msg);
``(None, {}, msg)`` on parse error. Shared by dispatch, display, and the
trajectory recorder so all three agree on the underlying tool."""
name = str(args.get("name") or "").strip()
if not name:
return None, {}, "tool_call requires a 'name' argument"
if name in BRIDGE_TOOL_NAMES:
return None, {}, f"tool_call cannot invoke '{name}' (it is itself a bridge tool)"
raw_args = args.get("arguments")
if raw_args is None:
raw_args = {}
if isinstance(raw_args, str):
try:
raw_args = json.loads(raw_args)
except json.JSONDecodeError as e:
return None, {}, f"tool_call 'arguments' is not valid JSON: {e}"
if not isinstance(raw_args, dict):
return None, {}, "tool_call 'arguments' must be an object"
if not is_deferrable_tool_name(name, load_config_readonly().effective_defer_tools):
return None, {}, (
f"'{name}' is not a deferrable tool. If it appears in the model-facing tools "
"list already, call it directly instead of via tool_call.")
return name, raw_args, None
__all__ = [
"TOOL_SEARCH_NAME", "TOOL_DESCRIBE_NAME", "TOOL_CALL_NAME", "BRIDGE_TOOL_NAMES",
"ToolSearchConfig", "CatalogEntry", "AssemblyResult", "load_config",
"is_deferrable_tool_name", "classify_tools", "estimate_tokens_from_schemas",
"should_activate", "build_catalog", "build_catalog_listing_with_form", "listing_token_budget",
"search_catalog", "bridge_tool_schemas", "assemble_tool_defs", "is_bridge_tool",
"dispatch_tool_search", "dispatch_tool_describe", "resolve_underlying_call",
"scoped_deferrable_names", "validate_deferred_call_args",
]