ACP entry.py fires MCP discovery in a background daemon thread, but
_make_agent snapshots tools once at build and never re-reads the registry.
Unlike CLI/TUI, ACP had no bounded wait before the snapshot and no
late-refresh for configured (config.yaml) MCP servers — a reachable-but-
slow server that finished after agent build was invisible for the whole
session.
Changes:
- acp_adapter/session.py (_make_agent): call wait_for_mcp_discovery()
before AIAgent construction, bounded by mcp_discovery_timeout (default
~1.5s). A dead server can't block; servers that miss the bound are
picked up by the late-refresh below.
- acp_adapter/server.py (_schedule_mcp_late_refresh): new method on
HermesACPAgent — if discovery is still in flight after session creation,
spawns an off-critical-path daemon that joins it (bounded 30s), then
rebuilds the tool snapshot via the shared refresh_agent_mcp_tools helper.
Cache-safe: only runs pre-first-turn (_user_turn_count/_api_call_count
both 0); once the user has sent a message the snapshot is frozen, exactly
as TUI PR #48403 does.
- Called from new_session, load_session, resume_session.
- Mirrors the TUI pattern (tui_gateway _schedule_mcp_late_refresh, PR
#48403) and the CLI pattern (get_tool_definitions → wait_for_mcp_discovery).
Tests:
- Replace the AST-based test (source-text inspection) with three
behavioral regression tests in tests/acp_adapter/test_acp_mcp_discovery.py:
1. Blocked discovery does not block startup (non-blocking contract)
2. Delayed discovery lands tools via late-refresh (pre-first-turn)
3. Late-refresh is cache-safe: skips rebuild after first turn
Addresses teknium1 review on PR #32811.
Sergey Prontsevich
640de6562e