hermes-agent/tests/tools/test_refresh_agent_mcp_tools.py
alt-glitch 88d523220f fix(mcp): address adversarial review round 2 (stale-publish race, parity holes)
Second review pass (Codex + Hermes subagent). Codex reproduced a real race with
a two-thread harness; both converged on the remaining issues.

- Generation-aware publish (fixes a lost-update race): two refresh callers (the
  late-refresh daemon and the between-turns prologue around turn 1) could each
  compute a snapshot outside the lock; a SLOWER caller holding an OLDER registry
  generation could acquire the publish lock after a newer caller and clobber it,
  deleting just-landed tools. refresh_agent_mcp_tools now captures
  registry._generation before computing and refuses to publish a stale set;
  agent._tool_snapshot_generation tracks the published generation.
- Context-engine routing names (_context_engine_tool_names) are now staged on a
  local and published atomically with the snapshot, and only claimed when this
  rebuild actually appended the schema — matching agent_init's dedup so a
  registry/plugin tool of the same name keeps its own dispatch. (Previously
  mutated live, before the publish lock, and on no-change refreshes.)
- CLI /reload-mcp: self.enabled_toolsets is resolved once at startup, so a
  server newly ENABLED in config mid-session wasn't picked up (TUI already
  re-resolved). Merge now-connected MCP server names into the override (unless
  the user pinned all/*), mirroring startup, and keep self.enabled_toolsets in
  sync. Closes the CLI/TUI parity hole.
- ACP (acp_adapter/server.py) routed through the shared helper — it was a 5th
  sibling rebuild that re-injected memory tools but NOT context-engine tools and
  bypassed the atomic/name-diff path (inert today, fragile).
- mcp_startup._resolve_discovery_timeout pulls its default from DEFAULT_CONFIG
  (single source of truth) instead of a stale hardcoded 5.0 literal.
- Tests: stale-generation-no-clobber, _skip_mcp_refresh honored, timeout
  fallback uses DEFAULT_CONFIG.
2026-06-19 11:57:43 -07:00

298 lines
11 KiB
Python

"""Tests for the shared MCP agent-tool refresh helper and discovery-wait bound.
``refresh_agent_mcp_tools`` is the single rebuild path used by the TUI
``reload.mcp`` RPC, the gateway reload, and the late-binding refresh thread —
so a slow MCP server that connects after the agent's one-time tool snapshot is
picked up everywhere identically. These assert the *contracts* those callers
rely on (name-based diff, in-place mutation, agent-scoped filtering) rather than
freezing any particular tool list.
"""
import threading
import types
from tools import mcp_tool
def _tool(name):
return {"type": "function", "function": {"name": name, "description": "", "parameters": {}}}
def _agent(tool_names, *, enabled=None, disabled=None):
a = types.SimpleNamespace()
a.tools = [_tool(n) for n in tool_names]
a.valid_tool_names = set(tool_names)
a.enabled_toolsets = enabled
a.disabled_toolsets = disabled
return a
def test_refresh_adds_late_landing_tools(monkeypatch):
"""A server that registers after build → its tools land in the snapshot."""
agent = _agent(["read_file", "terminal"])
new_defs = [_tool(n) for n in ("read_file", "terminal", "mcp_granola_get_account_info")]
monkeypatch.setattr(mcp_tool, "get_tool_definitions", lambda **kw: new_defs, raising=False)
# get_tool_definitions is imported inside the helper from model_tools, so patch there too.
import model_tools
monkeypatch.setattr(model_tools, "get_tool_definitions", lambda **kw: new_defs)
added = mcp_tool.refresh_agent_mcp_tools(agent)
assert added == {"mcp_granola_get_account_info"}
assert "mcp_granola_get_account_info" in agent.valid_tool_names
assert len(agent.tools) == 3
def test_refresh_no_change_returns_empty_and_leaves_agent_untouched(monkeypatch):
"""No new tools → empty set, and the snapshot object is not swapped."""
agent = _agent(["read_file", "terminal"])
original_tools = agent.tools
import model_tools
monkeypatch.setattr(
model_tools, "get_tool_definitions",
lambda **kw: [_tool("read_file"), _tool("terminal")],
)
added = mcp_tool.refresh_agent_mcp_tools(agent)
assert added == set()
assert agent.tools is original_tools # not replaced → no churn / no cache thrash
def test_refresh_detects_equal_size_swap(monkeypatch):
"""Name-based diff catches an add+remove of equal count (count-compare can't)."""
agent = _agent(["a", "old_mcp_tool"]) # 2 tools
import model_tools
# Same COUNT (2) but a different membership: old_mcp_tool removed, new added.
monkeypatch.setattr(
model_tools, "get_tool_definitions",
lambda **kw: [_tool("a"), _tool("new_mcp_tool")],
)
added = mcp_tool.refresh_agent_mcp_tools(agent)
assert added == {"new_mcp_tool"}
assert agent.valid_tool_names == {"a", "new_mcp_tool"}
assert "old_mcp_tool" not in agent.valid_tool_names
def test_refresh_passes_agent_toolset_filters(monkeypatch):
"""The rebuild re-derives with the agent's OWN enabled/disabled toolsets."""
agent = _agent(["a"], enabled=["coding", "granola"], disabled=["messaging"])
seen = {}
import model_tools
def _capture(**kw):
seen.update(kw)
return [_tool("a"), _tool("b")]
monkeypatch.setattr(model_tools, "get_tool_definitions", _capture)
mcp_tool.refresh_agent_mcp_tools(agent)
assert seen["enabled_toolsets"] == ["coding", "granola"]
assert seen["disabled_toolsets"] == ["messaging"]
def test_refresh_preserves_memory_provider_and_context_engine_tools(monkeypatch):
"""B1 regression: a rebuild must NOT drop post-build-injected tools.
get_tool_definitions() returns only the registry-derived tools. agent_init
appends memory-provider tools (mem0/honcho/…) and context-engine tools
(lcm_*) directly onto agent.tools AFTER that. A naive
`agent.tools = get_tool_definitions()` would silently delete them on every
refresh. The helper must re-inject them.
"""
# Agent already carries: a built-in, a memory-provider tool, a context tool.
agent = _agent(["read_file", "memory_search", "lcm_grep"])
# Provider exposes its schemas; context compressor exposes lcm_*.
agent._memory_manager = types.SimpleNamespace(
get_all_tool_schemas=lambda: [
{"name": "memory_search", "description": "", "parameters": {}}
]
)
agent.context_compressor = types.SimpleNamespace(
get_tool_schemas=lambda: [
{"name": "lcm_grep", "description": "", "parameters": {}}
]
)
agent._context_engine_tool_names = {"lcm_grep"}
import model_tools
# The registry now ALSO has a newly-connected MCP tool, but does NOT contain
# the memory/context tools (they're never in get_tool_definitions output).
monkeypatch.setattr(
model_tools, "get_tool_definitions",
lambda **kw: [_tool("read_file"), _tool("mcp_new_server_tool")],
)
added = mcp_tool.refresh_agent_mcp_tools(agent)
# The new MCP tool landed AND the injected families survived.
assert "mcp_new_server_tool" in agent.valid_tool_names
assert "memory_search" in agent.valid_tool_names # not clobbered
assert "lcm_grep" in agent.valid_tool_names # not clobbered
assert added == {"mcp_new_server_tool"}
def test_refresh_respects_context_engine_toolset_gate(monkeypatch):
"""#5544: context-engine tools must NOT be re-injected on a restricted
toolset. A platform with enabled_toolsets that excludes context_engine
must not get lcm_* leaked back in by a refresh."""
agent = _agent(["read_file"], enabled=["coding"]) # context_engine NOT enabled
agent.context_compressor = types.SimpleNamespace(
get_tool_schemas=lambda: [{"name": "lcm_grep", "description": "", "parameters": {}}]
)
agent._context_engine_tool_names = set()
import model_tools
monkeypatch.setattr(
model_tools, "get_tool_definitions",
lambda **kw: [_tool("read_file"), _tool("mcp_new_tool")],
)
mcp_tool.refresh_agent_mcp_tools(agent)
assert "mcp_new_tool" in agent.valid_tool_names # MCP tool still lands
assert "lcm_grep" not in agent.valid_tool_names # gated out (#5544)
def test_refreshed_tool_is_callable_through_valid_tool_names_guard(monkeypatch):
"""The whole point: a late tool, once refreshed, passes the name guard the
run loop uses to accept/reject tool calls (agent.valid_tool_names)."""
agent = _agent(["read_file"])
import model_tools
monkeypatch.setattr(
model_tools, "get_tool_definitions",
lambda **kw: [_tool("read_file"), _tool("mcp_granola_list_meetings")],
)
# Before refresh the run loop would reject the call ("Tool does not exist").
assert "mcp_granola_list_meetings" not in agent.valid_tool_names
mcp_tool.refresh_agent_mcp_tools(agent)
# After refresh the same guard accepts it AND it's in the tools= payload.
assert "mcp_granola_list_meetings" in agent.valid_tool_names
assert any(t["function"]["name"] == "mcp_granola_list_meetings" for t in agent.tools)
def test_refresh_is_thread_safe_under_concurrent_calls(monkeypatch):
"""Concurrent refreshes keep tools / valid_tool_names coherent.
The registry alternates between two DIFFERENT tool sets every call, so the
write path (publish) runs repeatedly rather than short-circuiting on the
no-change early return — this actually exercises the lock. The invariant:
a reader of ``valid_tool_names`` must always match ``agent.tools``, and the
final published pair must be one of the two valid sets (never a mix).
"""
agent = _agent(["a"])
import itertools
set_a = [_tool("a"), _tool("b")]
set_b = [_tool("a"), _tool("c")]
flip = itertools.cycle([set_a, set_b])
flip_lock = threading.Lock()
def _gtd(**kw):
with flip_lock:
return list(next(flip))
import model_tools
monkeypatch.setattr(model_tools, "get_tool_definitions", _gtd)
errors = []
def _worker():
try:
for _ in range(50):
mcp_tool.refresh_agent_mcp_tools(agent)
# Coherence invariant: the name set must match the tool list
# at every observation, never a torn cross-attribute state.
names = {t["function"]["name"] for t in agent.tools}
assert agent.valid_tool_names == names
assert names in ({"a", "b"}, {"a", "c"})
except Exception as exc: # pragma: no cover - failure path
errors.append(exc)
threads = [threading.Thread(target=_worker) for _ in range(4)]
for t in threads:
t.start()
for t in threads:
t.join(timeout=10)
assert not errors
assert agent.valid_tool_names in ({"a", "b"}, {"a", "c"})
# ── discovery-wait bound (mcp_discovery_timeout config) ──────────────────────
def test_resolve_discovery_timeout_explicit_wins(monkeypatch):
from hermes_cli import mcp_startup
assert mcp_startup._resolve_discovery_timeout(2.5) == 2.5
def test_resolve_discovery_timeout_reads_config(monkeypatch):
from hermes_cli import mcp_startup
import hermes_cli.config as cfg
monkeypatch.setattr(cfg, "load_config", lambda: {"mcp_discovery_timeout": 8.0})
assert mcp_startup._resolve_discovery_timeout(None) == 8.0
def test_resolve_discovery_timeout_falls_back_on_bad_value(monkeypatch):
from hermes_cli import mcp_startup
import hermes_cli.config as cfg
# Non-positive / unparsable → DEFAULT_CONFIG value, never hang.
default = float(cfg.DEFAULT_CONFIG.get("mcp_discovery_timeout", 1.5))
monkeypatch.setattr(cfg, "load_config", lambda: {"mcp_discovery_timeout": 0})
assert mcp_startup._resolve_discovery_timeout(None) == default
monkeypatch.setattr(cfg, "load_config", lambda: {"mcp_discovery_timeout": "oops"})
assert mcp_startup._resolve_discovery_timeout(None) == default
def test_stale_generation_refresh_does_not_clobber_newer(monkeypatch):
"""A slower refresh that computed an OLDER registry generation must not
overwrite a snapshot a newer-generation refresh already published."""
from tools import registry as _reg_mod
agent = _agent(["read_file"])
# A newer refresh already published generation = current+5, with two tools.
agent._tool_snapshot_generation = _reg_mod.registry._generation + 5
agent.tools = [_tool("read_file"), _tool("mcp_new_tool")]
agent.valid_tool_names = {"read_file", "mcp_new_tool"}
import model_tools
# This (stale) refresh computes only the old single-tool set.
monkeypatch.setattr(model_tools, "get_tool_definitions", lambda **kw: [_tool("read_file")])
added = mcp_tool.refresh_agent_mcp_tools(agent)
# Stale write rejected: the newer tool survives.
assert added == set()
assert "mcp_new_tool" in agent.valid_tool_names
def test_wait_returns_instantly_when_no_discovery_thread(monkeypatch):
"""The common case (no MCP / discovery done) pays ~0s regardless of bound."""
import time
from hermes_cli import mcp_startup
monkeypatch.setattr(mcp_startup, "_mcp_discovery_thread", None)
import hermes_cli.config as cfg
monkeypatch.setattr(cfg, "load_config", lambda: {"mcp_discovery_timeout": 999.0})
t0 = time.time()
mcp_startup.wait_for_mcp_discovery()
assert time.time() - t0 < 0.2 # never blocks on the bound when nothing's pending