import * as NodeCrypto from "node:crypto";import * as Cause from "effect/Cause";import * as Clock from "effect/Clock";import * as Context from "effect/Context";import * as Effect from "effect/Effect";import * as FileSystem from "effect/FileSystem";import * as Layer from "effect/Layer";import * as Option from "effect/Option";import * as Path from "effect/Path";import * as Schema from "effect/Schema";import * as Sink from "effect/Sink";import * as Stream from "effect/Stream";import type * as Types from "effect/Types";import { McpProtocol, McpSchema, McpServer, Tool } from "effect/unstable/ai";import { HttpRouter, HttpServerRequest, HttpServerResponse } from "effect/unstable/http"; import packageJson from "../../package.json" with { type: "json" };import * as ServerConfig from "../config.ts";import * as McpInvocationContext from "./McpInvocationContext.ts";import * as McpSessionRegistry from "./McpSessionRegistry.ts";import * as PreviewAutomationBroker from "./PreviewAutomationBroker.ts";import {  PreviewSnapshotToolkitHandlersLive,  PreviewStandardToolkitHandlersLive,} from "./toolkits/preview/handlers.ts";import {  PreviewSnapshotTool,  PreviewSnapshotToolkit,  PreviewStandardToolkit,} from "./toolkits/preview/tools.ts";import { PullRequestsToolkitHandlersLive } from "./toolkits/pullRequests/handlers.ts";import { PullRequestsToolkit } from "./toolkits/pullRequests/tools.ts"; const unauthorized = HttpServerResponse.jsonUnsafe(  {    error: "invalid_mcp_credential",    message: "A valid provider-scoped MCP bearer credential is required.",  },  {    status: 401,    headers: {      "cache-control": "no-store",      "www-authenticate": "Bearer",    },  },); type AuthenticatedHttpEffect = Effect.Effect<  HttpServerResponse.HttpServerResponse,  Types.unhandled,  McpInvocationContext.McpInvocationContext>; type McpAuthMiddleware = (  httpEffect: AuthenticatedHttpEffect,) => Effect.Effect<  HttpServerResponse.HttpServerResponse,  Types.unhandled,  HttpServerRequest.HttpServerRequest>; export const normalizeMcpHttpResponse = (  response: HttpServerResponse.HttpServerResponse,): HttpServerResponse.HttpServerResponse => {  const bodyIsEmpty =    response.body._tag === "Empty" ||    (response.body._tag === "Uint8Array" && response.body.contentLength === 0) ||    (response.body._tag === "Raw" && response.body.contentLength === 0);  return response.status === 200 && bodyIsEmpty    ? HttpServerResponse.setStatus(response, 202)    : response;}; const makeMcpAuthMiddleware = McpSessionRegistry.McpSessionRegistry.pipe(  Effect.map((registry): McpAuthMiddleware =>    Effect.fn("McpHttpServer.authenticateRequest")(function* (httpEffect) {      const request = yield* HttpServerRequest.HttpServerRequest;      const authorization = request.headers.authorization;      const token =        authorization?.startsWith("Bearer ") === true          ? authorization.slice("Bearer ".length).trim()          : "";      const invocation = yield* registry.resolve(token);      if (!invocation) {        // Without this the only symptom of a dead credential is the agent        // quietly losing the whole `t3-code` toolkit for the rest of its        // session, with nothing on the server to explain why.        yield* Effect.logWarning("rejected MCP request with an unusable credential", {          reason: token.length === 0 ? "missing_bearer_token" : "unknown_or_expired_token",        });        return unauthorized;      }      return yield* httpEffect.pipe(        Effect.provideService(McpInvocationContext.McpInvocationContext, invocation),        Effect.map(normalizeMcpHttpResponse),      );    }),  ),  Effect.withSpan("McpHttpServer.makeAuthMiddleware"),); const McpAuthMiddlewareLive = HttpRouter.middleware<{  provides: McpInvocationContext.McpInvocationContext;}>()(makeMcpAuthMiddleware).layer; /** * Claude Code drops every MCP result above 25k tokens (~100 KB of text) and * hands the agent a truncation notice instead, so a snapshot that carries the * full accessibility tree and 20 KB of page text loses its locators too. Keep * the text under that ceiling and tell the agent what was cut. */export const MAX_SNAPSHOT_TEXT_BYTES = 60_000;const MAX_SNAPSHOT_VISIBLE_TEXT_CHARS = 8_000;const MAX_SNAPSHOT_ELEMENT_NAME_CHARS = 200;const MAX_SNAPSHOT_LOG_ENTRIES = 40;const MAX_SNAPSHOT_LOG_TEXT_CHARS = 500;const MAX_SNAPSHOT_IDENTIFIER_CHARS = 2_048; const encodeJsonText = Schema.encodeSync(Schema.fromJsonString(Schema.Unknown));const utf8Length = (text: string) => Buffer.byteLength(text, "utf8");const cutText = (text: string, max: number) =>  text.length > max ? `${text.slice(0, max)}…` : text; /** Shortens every string field of a log entry; other fields pass through. */const cutEntryStrings = <A>(entry: A): A =>  typeof entry === "object" && entry !== null    ? (Object.fromEntries(        Object.entries(entry).map(([key, value]) => [          key,          typeof value === "string" ? cutText(value, MAX_SNAPSHOT_LOG_TEXT_CHARS) : value,        ]),      ) as A)    : entry; const hasLongString = (entry: unknown, max: number) =>  typeof entry === "object" &&  entry !== null &&  Object.values(entry).some((value) => typeof value === "string" && value.length > max); type SnapshotMetadata = {  readonly url: string;  readonly title: string;  readonly visibleText: string;  readonly interactiveElements: ReadonlyArray<{    readonly name: string;    readonly [key: string]: unknown;  }>;  readonly consoleEntries: ReadonlyArray<unknown>;  readonly networkEntries: ReadonlyArray<unknown>;  readonly actionTimeline: ReadonlyArray<unknown>;  readonly [key: string]: unknown;}; /** * Drops the accessibility tree, shortens page text, element names, identifiers, * and log strings, keeps only the newest log entries, and finally sheds * interactive elements until the JSON fits. Returns the text plus notes on * what is missing so the agent can reach for preview_evaluate. */const boundSnapshotMetadata = (  metadata: SnapshotMetadata,): { readonly text: string; readonly omitted: ReadonlyArray<string> } => {  const omitted: Array<string> = [];  const { accessibilityTree, ...withoutTree } = metadata;  if (accessibilityTree !== undefined) {    omitted.push("accessibilityTree (use interactiveElements locators or preview_evaluate)");  }  const tail = <A>(entries: ReadonlyArray<A>, label: string) => {    if (entries.length > MAX_SNAPSHOT_LOG_ENTRIES) {      omitted.push(`${entries.length - MAX_SNAPSHOT_LOG_ENTRIES} older ${label}`);    }    const kept = entries.slice(-MAX_SNAPSHOT_LOG_ENTRIES);    if (kept.some((entry) => hasLongString(entry, MAX_SNAPSHOT_LOG_TEXT_CHARS))) {      omitted.push(`${label} text after ${MAX_SNAPSHOT_LOG_TEXT_CHARS} characters`);    }    return kept.map(cutEntryStrings);  };  if (    metadata.url.length > MAX_SNAPSHOT_IDENTIFIER_CHARS ||    metadata.title.length > MAX_SNAPSHOT_IDENTIFIER_CHARS  ) {    omitted.push(`url or title after ${MAX_SNAPSHOT_IDENTIFIER_CHARS} characters`);  }  if (    metadata.interactiveElements.some(      (element) => element.name.length > MAX_SNAPSHOT_ELEMENT_NAME_CHARS,    )  ) {    omitted.push(`element names longer than ${MAX_SNAPSHOT_ELEMENT_NAME_CHARS} characters`);  }  if (metadata.visibleText.length > MAX_SNAPSHOT_VISIBLE_TEXT_CHARS) {    omitted.push(      `visibleText after ${MAX_SNAPSHOT_VISIBLE_TEXT_CHARS} characters (use preview_evaluate for more)`,    );  }  const bounded = {    ...withoutTree,    url: cutText(metadata.url, MAX_SNAPSHOT_IDENTIFIER_CHARS),    title: cutText(metadata.title, MAX_SNAPSHOT_IDENTIFIER_CHARS),    visibleText: cutText(metadata.visibleText, MAX_SNAPSHOT_VISIBLE_TEXT_CHARS),    interactiveElements: metadata.interactiveElements.map((element) => ({      ...element,      name: cutText(element.name, MAX_SNAPSHOT_ELEMENT_NAME_CHARS),    })),    consoleEntries: tail(metadata.consoleEntries, "console entries"),    networkEntries: tail(metadata.networkEntries, "network entries"),    actionTimeline: tail(metadata.actionTimeline, "action timeline entries"),  };   // Per-field caps do not sum below the ceiling: three log arrays of 40 capped  // entries alone can pass 60 KB. Shed the least useful lists first, halving  // one list per round, until the JSON fits. With every list empty the rest  // is bounded by the identifier and visibleText caps, so this terminates.  const shedOrder = [    "actionTimeline",    "networkEntries",    "consoleEntries",    "interactiveElements",  ] as const;  const lists: Record<(typeof shedOrder)[number], ReadonlyArray<unknown>> = {    interactiveElements: bounded.interactiveElements,    consoleEntries: bounded.consoleEntries,    networkEntries: bounded.networkEntries,    actionTimeline: bounded.actionTimeline,  };  const dropped: Record<(typeof shedOrder)[number], number> = {    interactiveElements: 0,    consoleEntries: 0,    networkEntries: 0,    actionTimeline: 0,  };  let text = encodeJsonText({ ...bounded, ...lists });  while (utf8Length(text) > MAX_SNAPSHOT_TEXT_BYTES) {    // Elements carry the locators, so they go last; logs shed newest-last.    const key =      shedOrder.find(        (candidate) => candidate !== "interactiveElements" && lists[candidate].length > 0,      ) ?? (lists.interactiveElements.length > 0 ? "interactiveElements" : undefined);    if (key === undefined) break;    const keep = Math.floor(lists[key].length / 2);    dropped[key] += lists[key].length - keep;    // slice(-0) keeps everything, so spell out the empty case.    lists[key] =      keep === 0        ? []        : key === "interactiveElements"          ? lists[key].slice(0, keep)          : lists[key].slice(-keep);    text = encodeJsonText({ ...bounded, ...lists });  }  for (const key of shedOrder) {    if (dropped[key] > 0) {      omitted.push(`${dropped[key]} of ${bounded[key].length} ${key}`);    }  }  return { text, omitted };}; export class PreviewScreenshotSaveError extends Schema.TaggedError<PreviewScreenshotSaveError>()(  "PreviewScreenshotSaveError",  { screenshotPath: Schema.String, cause: Schema.Defect() },) {  override get message(): string {    return `Could not save preview screenshot to ${this.screenshotPath}.`;  }} const MAX_SCREENSHOT_SITE_SLUG_LENGTH = 40; /** Hostname reduced to a filename-safe slug, matching the desktop's own screenshot names. */const screenshotSiteSlug = (rawUrl: string): string => {  try {    const slug = new URL(rawUrl).hostname      .toLowerCase()      .replace(/[^a-z0-9]+/g, "-")      .replace(/^-+|-+$/g, "")      .slice(0, MAX_SCREENSHOT_SITE_SLUG_LENGTH)      .replace(/-+$/g, "");    return slug || "site";  } catch {    return "site";  }}; /** Writes the snapshot PNG under the browser artifacts directory and returns its path. */const saveScreenshot = Effect.fn("McpHttpServer.saveScreenshot")(function* (  pageUrl: string,  data: Uint8Array,) {  const config = yield* ServerConfig.ServerConfig;  const fileSystem = yield* FileSystem.FileSystem;  const path = yield* Path.Path;  const millis = yield* Clock.currentTimeMillis;  // Two saves in the same millisecond must not overwrite each other.  const fileName = `browser-screenshot-${screenshotSiteSlug(pageUrl)}-${millis.toString(36)}-${NodeCrypto.randomUUID().slice(0, 8)}.png`;  const screenshotPath = path.join(config.browserArtifactsDir, fileName);  yield* fileSystem.makeDirectory(config.browserArtifactsDir, { recursive: true }).pipe(    Effect.andThen(fileSystem.writeFile(screenshotPath, data)),    Effect.mapError((cause) => new PreviewScreenshotSaveError({ screenshotPath, cause })),  );  return screenshotPath;}); const previewSnapshotFailure = <E>(cause: Cause.Cause<E>) => {  if (Cause.hasInterrupts(cause) || cause.reasons.some(Cause.isDieReason)) {    return Effect.failCause(cause).pipe(Effect.orDie);  }  const failures = cause.reasons.filter(Cause.isFailReason);  const firstFailure = failures[0]?.error;  const errorTag =    typeof firstFailure === "object" &&    firstFailure !== null &&    "_tag" in firstFailure &&    typeof firstFailure._tag === "string"      ? firstFailure._tag      : "PreviewSnapshotError";  const result = new McpSchema.CallToolResult({    isError: true,    structuredContent: {      error: {        _tag: errorTag,        operation: "snapshot",        failureCount: failures.length,      },    },    // Agents usually see only the text content, so name the tag there too.    content: [{ type: "text", text: `Preview snapshot failed: ${errorTag}.` }],  });  return Effect.logWarning("preview snapshot failed", {    operation: "snapshot",    errorTag,    failureCount: failures.length,  }).pipe(Effect.as(result));}; const registerPreviewSnapshot = Effect.fn("McpHttpServer.registerPreviewSnapshot")(function* () {  const server = yield* McpServer.McpServer;  const broker = yield* PreviewAutomationBroker.PreviewAutomationBroker;  // The MCP tool runner only supplies the client, so hand the save path its services here.  const saveServices = yield* Effect.context<    ServerConfig.ServerConfig | FileSystem.FileSystem | Path.Path  >();  const built = yield* PreviewSnapshotToolkit;  const tool = PreviewSnapshotTool;  yield* server.addTool({    tool: new McpSchema.Tool({      name: tool.name,      description: Tool.getDescription(tool),      inputSchema: Tool.getJsonSchema(tool),      annotations: {        ...Context.getOption(tool.annotations, Tool.Title).pipe(          Option.map((title) => ({ title })),          Option.getOrUndefined,        ),        readOnlyHint: Context.get(tool.annotations, Tool.Readonly),        destructiveHint: Context.get(tool.annotations, Tool.Destructive),        idempotentHint: Context.get(tool.annotations, Tool.Idempotent),        openWorldHint: Context.get(tool.annotations, Tool.OpenWorld),      },    }),    annotations: tool.annotations,    handle: (payload) =>      Effect.withFiber((fiber) => {        const invocation = Context.getUnsafe(          fiber.context,          McpInvocationContext.McpInvocationContext,        );        return built.handle("preview_snapshot", payload).pipe(          Stream.unwrap,          Stream.run(Sink.last()),          Effect.flatMap(Effect.fromOption),          Effect.provideService(PreviewAutomationBroker.PreviewAutomationBroker, broker),          Effect.provideService(McpInvocationContext.McpInvocationContext, invocation),          Effect.flatMap(({ encodedResult }) =>            Effect.gen(function* () {              const snapshot = encodedResult as SnapshotMetadata & {                readonly url: string;                readonly screenshot: {                  readonly mimeType: "image/png";                  readonly data: string;                  readonly width: number;                  readonly height: number;                };              };              const { screenshot, ...page } = snapshot;              const png = new Uint8Array(Buffer.from(screenshot.data, "base64"));              const screenshotPath =                payload?.save === true ? yield* saveScreenshot(snapshot.url, png) : undefined;              const metadata = {                ...page,                screenshot: {                  mimeType: screenshot.mimeType,                  width: screenshot.width,                  height: screenshot.height,                },                ...(screenshotPath === undefined ? {} : { screenshotPath }),              };              const bounded = boundSnapshotMetadata(metadata);              return new McpSchema.CallToolResult({                isError: false,                structuredContent: metadata,                content: [                  { type: "text", text: bounded.text },                  ...(bounded.omitted.length === 0                    ? []                    : [                        {                          type: "text" as const,                          text: `Snapshot text was bounded. Omitted: ${bounded.omitted.join("; ")}.`,                        },                      ]),                  ...(payload?.includeImage === false                    ? []                    : [{ type: "image" as const, data: png, mimeType: screenshot.mimeType }]),                ],              });            }),          ),          Effect.provide(saveServices),          Effect.matchCauseEffect({            onFailure: previewSnapshotFailure,            onSuccess: Effect.succeed,          }),        );      }),  });}); const PreviewStandardToolkitRegistrationLive = McpServer.toolkit(PreviewStandardToolkit).pipe(  Layer.provide(PreviewStandardToolkitHandlersLive),); const PreviewSnapshotRegistrationLive = Layer.effectDiscard(registerPreviewSnapshot()).pipe(  Layer.provide(PreviewSnapshotToolkitHandlersLive),); export const PreviewToolkitRegistrationLive = Layer.mergeAll(  PreviewStandardToolkitRegistrationLive,  PreviewSnapshotRegistrationLive,); export const PullRequestsToolkitRegistrationLive = McpServer.toolkit(PullRequestsToolkit).pipe(  Layer.provide(PullRequestsToolkitHandlersLive),); const McpTransportLive = McpServer.layerHttp({  name: "T3 Code",  version: packageJson.version,  path: "/mcp",  protocols: [McpProtocol.v2025_06_18],}).pipe(Layer.provide(McpAuthMiddlewareLive)); export const layer = Layer.mergeAll(  PreviewToolkitRegistrationLive,  PullRequestsToolkitRegistrationLive,).pipe(Layer.provideMerge(McpTransportLive));