Brain MCP brain_submit_learning tags array serialization:

Brain MCP brain_submit_learning tags array serialization: PATH-DEPENDENT behavior, not universally broken or fixed. (1) Direct MCP calls (Claude Code SSH → streamable-HTTP) handle multi-element arrays correctly — confirmed with 5-element array (learning #135). (2) Paperclip agent container instances (Claude Code CLI inside Docker) intermittently serialize multi-element arrays as strings instead of arrays, causing Pydantic list_type validation failure. Single-element arrays pass from both paths. Root cause: Claude Code CLI tool call JSON serialization varies by model response formatting — the MCP transport layer between CLI and server doesn’t normalize array types. Workaround for agents: use single-element tags or comma-separated single string when submitting from Paperclip agent runs. No workaround needed for Claude Code direct sessions. Parameter note: use agent_id (not source_agent) — source_agent is not a valid parameter.