docs(acp): clarify mcp_config is a shared field, not ACP-only

[simonrosenberg]

What

ACPAgentSettings now accepts mcp_config (the SDK forwards its MCP servers to the ACP subprocess at session creation — see OpenHands/software-agent-sdk#3458).

This clarifies on ACP_SETTINGS_KEYS that mcp_config is deliberately excluded from this ACP-exclusive allow-list.

Why

ACP_SETTINGS_KEYS is used to (a) copy ACP-only fields into an ACP payload and (b) strip them when switching to a non-ACP variant. mcp_config is shared with the OpenHands variant — adding it here would cause clients to delete mcp_config when switching agent kinds (and, in the agent-canvas adapter, would strip it right after the OpenHands builder preserved it). It must be handled per-variant like llm / agent_context, not stripped.

Comment-only change. tsc build + prettier + eslint clean.

Part of OpenHands/agent-canvas#993.

🤖 Generated with Claude Code

[simonrosenberg]

Closing as unnecessary. This was a comment-only clarification on ACP_SETTINGS_KEYS, but that constant is only re-exported from this package (not used internally), and its one consumer (agent-canvas) keeps its own local copy. The useful insight — mcp_config is a shared field, not ACP-only, so it must not be stripped on agent-kind switches — is already captured where it matters in the SDK and agent-canvas changes.

The ACP-MCP feature ships fully via OpenHands/software-agent-sdk#3458 + OpenHands/agent-canvas#995; neither depends on this. No code change is needed here.