• effects/node: limit ReadFile to Bun's bigint size constraint (131,072 bytes) for cross-runtime compatibility; add maxLength and maxLengthBytes constants #1121
• mcp: extract the declarative tool-registry pattern into reusable builders (ToolEntry, toolEntry, fromRegistry, errorResult), removing ~100 lines of dispatch boilerplate per MCP server #1119
• cas/mcp: refactor tool definitions from a hardcoded array plus switch to a data-driven registry, so adding a tool is additive #1118