Days Until

days

Pick a date below

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\n\n\n`;\n\n// ── Demo page ──────────────────────────────────────────────────────────────────\n\nconst DEMO_PAGE = `\n\n\n\nTime MCP Server — Demo\n\n\n\n\n

⏰ Time MCP Server

A Model Context Protocol server with MCP Apps UI extension (SEP-1865) — built on Val Town

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\n 🧪 MCP Apps Extension — This server implements the proposed MCP Apps UI extension (SEP-1865, Nov 2025).\n Tools expose ui:// resources via _meta.ui/resourceUri. Hosts that support the extension render them as sandboxed iframes.\n The live UI previews below show what those iframes look like. Non-UI hosts get clean text fallbacks.\n

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🛠 Tools — try them live

Tool 1

current_time

Get the current date and time in any IANA timezone.

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Result will appear here...

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Tool 2

days_until

Calculate days until (or since) a given date.

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Result will appear here...

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Tool 3

time_in_timezones

Get current time across multiple timezones at once.

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Result will appear here...

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MCP JSON-RPC

Raw tools/list

See the raw MCP tools/list response, including _meta.ui/resourceUri fields.

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Result will appear here...

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🖼 MCP Apps UI Resources SEP-1865

ui://time/clock → text/html+mcp

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ui://time/days-until → text/html+mcp

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\n\n\n\n`;\n\n// ── Main handler ───────────────────────────────────────────────────────────────\n\nexport default async function (req: Request): Promise {\n if (req.method === \"OPTIONS\") {\n return new Response(null, { headers: CORS_HEADERS });\n }\n\n // Serve demo or UI resources on GET\n if (req.method === \"GET\") {\n const url = new URL(req.url);\n const ui = url.searchParams.get(\"ui\");\n if (ui === \"clock\") {\n return new Response(CLOCK_UI, { headers: { \"Content-Type\": \"text/html\" } });\n }\n if (ui === \"days-until\") {\n return new Response(DAYS_UNTIL_UI, { headers: { \"Content-Type\": \"text/html\" } });\n }\n return new Response(DEMO_PAGE, { headers: { \"Content-Type\": \"text/html\" } });\n }\n\n if (req.method !== \"POST\") {\n return new Response(\"Method not allowed\", { status: 405 });\n }\n\n try {\n const body = await req.json();\n const { method, id, params } = body;\n\n console.log(`MCP request: ${method}`, params);\n\n // ── initialize ──\n if (method === \"initialize\") {\n return jsonRpc(id, {\n protocolVersion: \"2024-11-05\",\n capabilities: { tools: {}, resources: {} },\n serverInfo: { name: \"time-mcp\", version: \"2.0.0\" },\n });\n }\n\n // ── tools/list — with MCP Apps _meta ──\n if (method === \"tools/list\") {\n const base = new URL(req.url).origin + new URL(req.url).pathname.replace(/\\/$/, \"\");\n return jsonRpc(id, {\n tools: [\n {\n name: \"current_time\",\n description: \"Get the current date and time in a given timezone (defaults to UTC)\",\n inputSchema: {\n type: \"object\",\n properties: {\n timezone: {\n type: \"string\",\n description: \"IANA timezone name e.g. 'America/Sao_Paulo'. Defaults to UTC.\",\n },\n },\n },\n _meta: { \"ui/resourceUri\": \"ui://time/clock\" },\n },\n {\n name: \"days_until\",\n description: \"Calculate how many days until (or since) a given date\",\n inputSchema: {\n type: \"object\",\n properties: {\n date: { type: \"string\", description: \"Target date in YYYY-MM-DD format\" },\n timezone: { type: \"string\", description: \"IANA timezone for 'today'. Defaults to UTC.\" },\n },\n required: [\"date\"],\n },\n _meta: { \"ui/resourceUri\": \"ui://time/days-until\" },\n },\n {\n name: \"time_in_timezones\",\n description: \"Get the current time in multiple timezones at once\",\n inputSchema: {\n type: \"object\",\n properties: {\n timezones: {\n type: \"array\",\n items: { type: \"string\" },\n description: \"List of IANA timezone names\",\n },\n },\n required: [\"timezones\"],\n },\n },\n ],\n });\n }\n\n // ── resources/list — UI resources ──\n if (method === \"resources/list\") {\n return jsonRpc(id, {\n resources: [\n {\n uri: \"ui://time/clock\",\n name: \"Live Clock\",\n description: \"An interactive clock widget with timezone selector\",\n mimeType: \"text/html+mcp\",\n },\n {\n uri: \"ui://time/days-until\",\n name: \"Days Until Calculator\",\n description: \"Interactive countdown to any date\",\n mimeType: \"text/html+mcp\",\n },\n ],\n });\n }\n\n // ── resources/read — serve the HTML ──\n if (method === \"resources/read\") {\n const uri = params?.uri;\n if (uri === \"ui://time/clock\") {\n return jsonRpc(id, {\n contents: [{ uri, mimeType: \"text/html+mcp\", text: CLOCK_UI }],\n });\n }\n if (uri === \"ui://time/days-until\") {\n return jsonRpc(id, {\n contents: [{ uri, mimeType: \"text/html+mcp\", text: DAYS_UNTIL_UI }],\n });\n }\n return jsonRpc(id, null, { code: -32602, message: `Unknown resource: ${uri}` });\n }\n\n // ── tools/call ──\n if (method === \"tools/call\") {\n const toolName = params?.name;\n const args = params?.arguments || {};\n\n if (toolName === \"current_time\") {\n const tz = args.timezone || \"UTC\";\n try {\n const now = new Date();\n const formatted = now.toLocaleString(\"en-US\", {\n timeZone: tz,\n weekday: \"long\",\n year: \"numeric\",\n month: \"long\",\n day: \"numeric\",\n hour: \"2-digit\",\n minute: \"2-digit\",\n second: \"2-digit\",\n timeZoneName: \"short\",\n });\n return jsonRpc(id, {\n content: [{ type: \"text\", text: `Current time in ${tz}: ${formatted}` }],\n });\n } catch {\n return jsonRpc(id, null, { code: -32602, message: `Unknown timezone: ${tz}` });\n }\n }\n\n if (toolName === \"days_until\") {\n const tz = args.timezone || \"UTC\";\n try {\n const target = new Date(args.date + \"T00:00:00\");\n if (isNaN(target.getTime())) {\n return jsonRpc(id, null, { code: -32602, message: `Invalid date: ${args.date}` });\n }\n const todayStr = new Date().toLocaleDateString(\"en-CA\", { timeZone: tz });\n const today = new Date(todayStr + \"T00:00:00\");\n const diff = Math.round((target.getTime() - today.getTime()) / (1000 * 60 * 60 * 24));\n const dayName = target.toLocaleDateString(\"en-US\", { weekday: \"long\", timeZone: \"UTC\" });\n const dateStr = target.toLocaleDateString(\"en-US\", { year: \"numeric\", month: \"long\", day: \"numeric\", timeZone: \"UTC\" });\n let text: string;\n if (diff === 0) text = `${dateStr} (${dayName}) is today!`;\n else if (diff > 0) text = `${dateStr} (${dayName}) is in ${diff} day${diff === 1 ? \"\" : \"s\"}.`;\n else text = `${dateStr} (${dayName}) was ${Math.abs(diff)} day${Math.abs(diff) === 1 ? \"\" : \"s\"} ago.`;\n return jsonRpc(id, { content: [{ type: \"text\", text }] });\n } catch {\n return jsonRpc(id, null, { code: -32602, message: \"Error processing date\" });\n }\n }\n\n if (toolName === \"time_in_timezones\") {\n const zones: string[] = args.timezones || [];\n const lines = zones.map((tz) => {\n try {\n const t = new Date().toLocaleString(\"en-US\", {\n timeZone: tz,\n hour: \"2-digit\",\n minute: \"2-digit\",\n weekday: \"short\",\n timeZoneName: \"short\",\n });\n return `${tz}: ${t}`;\n } catch {\n return `${tz}: (unknown timezone)`;\n }\n });\n return jsonRpc(id, { content: [{ type: \"text\", text: lines.join(\"\\n\") }] });\n }\n\n return jsonRpc(id, null, { code: -32601, message: `Unknown tool: ${toolName}` });\n }\n\n if (method === \"notifications/initialized\") {\n return new Response(null, { status: 204 });\n }\n\n return jsonRpc(id, null, { code: -32601, message: `Method not found: ${method}` });\n } catch (err) {\n console.error(\"MCP error:\", err);\n return jsonRpc(0, null, { code: -32700, message: \"Parse error\" });\n }\n}\n","deleted","label",[100],"permalink","https://www.val.town/x/dcm31/timeMcp/code/main.ts","extension","actionData","errors"]