OMP session/new was dying with opaque "Internal error" when fusion-custom-tools
MCP pointed at a missing schema server, or when bare models hit unauthenticated
providers. Prefer data.details in diagnostics, resolve mcp-schema-server.cjs
from multiple package layouts, skip the tool bridge when the asset is missing,
drop stdio MCP entries whose command path does not exist, and forward common
provider env keys (ZAI/MiniMax/Kimi) into the ACP subprocess.
b8cd3d21fb