runtime.ts

/**
 * Agent backend for the Slack triage assistant.
 *
 * This is the brain behind the Slack bridge: a single CopilotKit
 * `BuiltInAgent` (LLM + MCP) served over AG-UI by a `CopilotSseRuntime`.
 * It replaces the old vendored Python/LangGraph showcase backend — there
 * is no Python, no `langgraph dev`, no A2UI middleware. Everything is a
 * few dozen lines of TypeScript.
 *
 * What it does
 * ------------
 * The agent connects to **Linear** and **Notion** via their MCP servers
 * and acts as an on-call / triage assistant inside Slack: it pulls and
 * files Linear issues, finds Notion runbooks, and writes incident
 * threads up as Notion postmortems. The data access is entirely MCP —
 * the agent discovers the available tools (list/search/create issues,
 * search/create pages) from each server at runtime.
 *
 * The Slack-side primitives (read_thread, the confirm_write HITL picker,
 * the issue/page Block Kit components) are forwarded to the agent as
 * client-provided tools by the bridge on every run — see `app/index.ts`.
 *
 * Auth & deployment
 * -----------------
 * Every connection is env-driven, so the same process runs locally and
 * deployed — only the env differs (see `.env.example`):
 *
 *   - Linear: the hosted MCP accepts a raw API key as a bearer token, so
 *     we connect straight to `LINEAR_MCP_URL` with `LINEAR_API_KEY`.
 *   - Notion: run the official `@notionhq/notion-mcp-server` as a
 *     Streamable-HTTP sidecar (`pnpm notion-mcp` locally, a second
 *     process/container in prod) and point `NOTION_MCP_URL` /
 *     `NOTION_MCP_AUTH_TOKEN` at it.
 *
 * A server is only wired up when its credentials are present, so the bot
 * runs Linear-only, Notion-only, or both.
 *
 * Exposed route (the bridge's `AGENT_URL`):
 *   POST http://localhost:8200/api/copilotkit/agent/triage/run
 */
import "dotenv/config";
import { createServer } from "node:http";
import {
  BuiltInAgent,
  CopilotSseRuntime,
  resolveModel,
} from "@copilotkit/runtime/v2";
import type {
  BuiltInAgentModel,
  MCPClientConfig,
} from "@copilotkit/runtime/v2";
import { createCopilotNodeListener } from "@copilotkit/runtime/v2/node";

/**
 * An HTTP MCP server that injects a static `Authorization: Bearer` on
 * every outbound request. `MCPClientConfigHTTP` has no `headers` field;
 * the SDK's documented extension point is `options.fetch`, so we wrap
 * `fetch` to set the header (mirrors how the runtime injects its own
 * intelligence-MCP credentials).
 */
function bearerMcpServer(url: string, token: string): MCPClientConfig {
  return {
    type: "http",
    url,
    options: {
      fetch: async (req, init) => {
        const headers = new Headers(init?.headers);
        headers.set("Authorization", `Bearer ${token}`);
        return globalThis.fetch(req, { ...init, headers });
      },
    },
  };
}

const LINEAR_TEAM_KEY = process.env["LINEAR_TEAM_KEY"] ?? "CPK";

const mcpServers: MCPClientConfig[] = [];

if (process.env["LINEAR_API_KEY"]) {
  mcpServers.push(
    bearerMcpServer(
      process.env["LINEAR_MCP_URL"] ?? "https://mcp.linear.app/mcp",
      process.env["LINEAR_API_KEY"],
    ),
  );
}

if (process.env["NOTION_MCP_AUTH_TOKEN"]) {
  mcpServers.push(
    bearerMcpServer(
      process.env["NOTION_MCP_URL"] ?? "http://127.0.0.1:3001/mcp",
      process.env["NOTION_MCP_AUTH_TOKEN"],
    ),
  );
}

if (mcpServers.length === 0) {
  console.warn(
    "[slack-runtime] No MCP servers configured. Set LINEAR_API_KEY and/or " +
      "NOTION_MCP_AUTH_TOKEN in .env — without them the bot can chat but " +
      "can't read or write Linear/Notion.",
  );
}

const SYSTEM_PROMPT = [
  "You are an on-call triage assistant living in a Slack workspace. You help",
  "an engineering team turn incident chatter into tracked work: you pull and",
  "file Linear issues, find Notion runbooks, and write incident threads up as",
  "Notion postmortems.",
  "",
  "Data access:",
  "- Linear and Notion are connected via MCP. Use those tools to search, read,",
  `  and create issues and pages. The default Linear team is "${LINEAR_TEAM_KEY}"`,
  "  unless the user names another team.",
  "",
  "Linear tool tips (the filters are picky — follow these to avoid empty results):",
  `- Pass the team KEY directly to list_issues, e.g. {team: "${LINEAR_TEAM_KEY}"}. Do`,
  "  NOT call list_teams to look a team up by its key — list_teams matches the",
  '  team\'s full NAME, not its key, so a key like "CPK" returns nothing. If you',
  "  must resolve a team, use get_team with the key.",
  '- For "my issues" / "assigned to me": set assignee to the requesting user\'s',
  '  email (it\'s in your context) or the literal "me" — both work.',
  "- The state filter takes a Linear state TYPE (backlog, unstarted, started,",
  '  completed, canceled) or a specific state name — NOT "open" or "closed". For',
  '  "open" issues, OMIT the state filter entirely (state:"open" returns nothing).',
  '- There is no cycle:"current"/"active" value. For "this cycle", just list the',
  "  team's issues (omit the cycle filter) unless the user names a cycle number.",
  "- QUERY ONCE. Call list_issues a SINGLE time with the team key + any needed",
  "  filter. Do NOT paginate or re-run it with different filter combinations to",
  "  gather every issue — one query is enough. If the result set is large, render",
  "  the ~15 most recent and note the rest (e.g. 'showing 15 of 39') instead of",
  "  dumping the whole backlog; a 39-row card is noise, not an answer.",
  "- Use get_issue for one issue; render it with issue_card.",
  "- To act on a Slack conversation (e.g. 'write this thread up'), call the",
  "  read_thread tool to fetch the messages first — never invent thread content.",
  "",
  "Files & visuals: uploaded files arrive in the message as content you can",
  "read — images and PDFs directly, and CSV/JSON/text as decoded text. When a",
  "user uploads data and wants a chart, parse it and call render_chart with a",
  "Chart.js config OBJECT — pick a sensible type (bar/line/pie) and inline the",
  "data. When the user wants the data itself shown as a table (not a chart),",
  "call render_table with columns + rows (each row an array of cell values in",
  "column order; set a column's align to 'right' for numeric columns). When",
  "asked to diagram a flow/architecture/timeline, call render_diagram with",
  "Mermaid source. render_chart and render_diagram post an image; render_table",
  "posts a Slack table. If render_diagram returns an error, fix the Mermaid and",
  "retry. These are read/reply actions — no confirm_write needed.",
  '- Always NAME the file you acted on in your reply (e.g. "Charting',
  "  `incidents-2026.csv`…\"), so it's clear which upload a chart came from.",
  "- If more than one file is in the thread and the request doesn't make clear",
  "  which one to use, ASK which file (list them by name) instead of guessing.",
  "",
  "Acting per-user: each turn's context names the Requesting Slack user, with",
  'their name and email. When someone says "my issues", "assigned to me", or',
  '"file this for me", use that email/name to find their Linear user, then:',
  "- Querying: filter Linear by that person (assignee), so each user gets THEIR",
  "  issues — not everyone's.",
  "- Creating: set the new issue's assignee to that person and @mention them.",
  "  (Heads up: issues are still authored by the bot's API key, so the Linear",
  "  'creator' is the bot — assignee is how you attribute work to the requester.)",
  "Never assume every request is from the same person; always use the requester",
  "named in context. If their email isn't in context, say so rather than guessing.",
  "",
  "RENDERING — THIS IS A HARD RULE. Whenever your answer contains structured",
  "output, you MUST call the matching render tool and let IT draw the card. Do",
  "NOT reproduce that content as Markdown bullets, a table, or prose — a hand-",
  "written list/table/card is a BUG, not an answer. Map the request to a tool and",
  "call it FIRST, then add at most one short sentence around it:",
  "- Several Linear issues          -> issue_list",
  "- A single Linear issue          -> issue_card (and right after you create one, justCreated: true)",
  "- Notion pages                   -> page_list",
  "- Tabular data / 'as a table'    -> render_table (columns + rows)",
  "- A status / metrics / health summary (counts, KPIs, label/value pairs)",
  "                                 -> show_status (heading + fields:[{label,value}])",
  "- An incident / outage           -> show_incident (id, title, severity SEV1|SEV2|SEV3,",
  "                                    summary) — an interactive card with Acknowledge/Escalate",
  "- A set of links / runbooks      -> show_links (heading + links:[{label,url}])",
  "- A chart from data              -> render_chart;   a flow/architecture/timeline -> render_diagram",
  "If the user explicitly asks for a card/table/incident/status/links, calling the",
  "tool IS the whole answer — never describe what the card 'would' contain in prose.",
  "Your text message alongside a rendered card MUST be empty or ONE short line (e.g.",
  '"Open CPK issues:"). NEVER restate the issues/rows/fields as text after rendering',
  "— the card already shows them, and a duplicate text wall is the single most",
  "annoying thing you can do. Render, then stop.",
  "- ALWAYS populate each issue's state and priority as plain strings (e.g.",
  '  state:"In Progress", priority:"High") on the component props — the cards',
  "  use them for the status dot and the colored border. The Linear MCP returns",
  '  priority as an object {value, name}; pass its NAME string (e.g. "High"),',
  "  not the object. Map the issue's workflow status into state. Include",
  "  assignee, url, and updated too when you have them.",
  "",
  "WRITE GATING: a 'write' is CREATING or MODIFYING something in Linear or Notion",
  "(create_issue, update_issue, create_page, …). ONLY before such a write, call the",
  "confirm_write tool with a one-line summary and wait for approval; perform the",
  "write only if confirmed. Rendering a card/table (issue_list, issue_card,",
  "show_incident, show_status, show_links, render_table, render_chart/diagram) and",
  "any read (search/list/get) are NOT writes — never gate them, and never add an",
  "'I'll need approval' disclaimer to a pure render or read.",
].join("\n");

const model =
  (process.env["AGENT_MODEL"] as BuiltInAgentModel) ?? "openai/gpt-5.5";

// Fail loud at startup on a misspelled provider/model rather than on the
// first agent invocation. (The model's API key is read from env at run time.)
try {
  resolveModel(model);
} catch (err) {
  console.error(`[slack-runtime] invalid AGENT_MODEL "${model}":`, err);
  process.exit(1);
}

const agent = new BuiltInAgent({
  model,
  // Triage chains several MCP calls per turn (search -> read -> confirm ->
  // create), so give the agent room to loop.
  maxSteps: Number(process.env["AGENT_MAX_STEPS"] ?? 12),
  mcpServers,
  prompt: SYSTEM_PROMPT,
});

const runtime = new CopilotSseRuntime({
  agents: { triage: agent },
});

const listener = createCopilotNodeListener({
  runtime,
  basePath: "/api/copilotkit",
  cors: true,
});

const port = Number(process.env["PORT"] ?? 8200);
createServer(listener).listen(port, () => {
  console.log(
    `[slack-runtime] listening on http://localhost:${port}/api/copilotkit/agent/triage/run`,
  );
  const connected = [
    process.env["LINEAR_API_KEY"] ? "Linear" : null,
    process.env["NOTION_MCP_AUTH_TOKEN"] ? "Notion" : null,
  ].filter(Boolean);
  console.log(
    `[slack-runtime] agent "triage" ready · MCP: ${
      connected.length ? connected.join(", ") : "none"
    }`,
  );
});