{"version":"2.1.280","anchor":"new-mcp-tool-uimeta-passthrough-from-meta","canonical_anchor":"new-mcp-tool-uimeta-passthrough-from-meta","heading":"New MCP tool uiMeta passthrough from _meta","tier":"use","area":"MCP","url":"https:\/\/changelogs.core-directive.com\/v\/2.1.280\/e\/new-mcp-tool-uimeta-passthrough-from-meta","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.280","markdown":"### New MCP tool `uiMeta` passthrough from `_meta`\n\nMCP tools can now pass a small `ui`-related metadata block through to the tool definition\n\n**Unclear.** The finding does not say what the `ui` field is used for or what the other allow-listed symbol-keyed field is.\n\n**What**\n\nMCP (Model Context Protocol, the standard Claude Code uses to connect external tools) tools can now supply a `uiMeta` value, extracted from an allow-listed subset of the tool's `_meta` field, including a `ui` key. When present, this `uiMeta` is attached to the tool's internal info and then passed back out as `_meta` when the tool definition is built.\n\n**Why**\n\nThis lets an MCP tool pass a small piece of UI-related metadata through Claude Code unchanged, so the host application or interface can use it, without that data being altered or stripped along the way.\n\n- Area: MCP\n- Names: `uiMeta`\n- Tier: Use it now\n- Useful: 3\/5\n- Signal: 2\/5"}