Sentry MCP

import { Hono } from "hono"; import type { AuthRequest } from "@cloudflare/workers-oauth-provider"; import { clientIdAlreadyApproved } from "../../lib/approval-dialog"; import type { Env, WorkerProps } from "../../types"; import { SENTRY_TOKEN_URL } from "../constants"; import { exchangeCodeForAccessToken } from "../helpers"; import { verifyAndParseState, type OAuthState } from "../state"; import { logWarn } from "@sentry/mcp-server/telem/logging"; import { parseSkills, getScopesForSkills } from "@sentry/mcp-server/skills"; /** * Extended AuthRequest that includes skills */ interface AuthRequestWithSkills extends AuthRequest { skills?: unknown; // Skill-based authorization system } /** * OAuth Callback Endpoint (GET /oauth/callback) * * This route handles the callback from Sentry after user authentication. * It exchanges the temporary code for an access token, then stores some * user metadata & the auth token as part of the 'props' on the token passed * down to the client. It ends by redirecting the client back to _its_ callback URL */ // Export Hono app for /callback endpoint export default new Hono<{ Bindings: Env }>().get("/", async (c) => { // Verify and parse the signed state let parsedState: OAuthState; try { const rawState = c.req.query("state") ?? ""; parsedState = await verifyAndParseState(rawState, c.env.COOKIE_SECRET); } catch (err) { logWarn("Invalid state received on OAuth callback", { loggerScope: ["cloudflare", "oauth", "callback"], extra: { error: String(err) }, }); return c.text("Invalid state", 400); } // Reconstruct oauth request info exactly as provided by downstream client const oauthReqInfo = parsedState.req as unknown as AuthRequestWithSkills; if (!oauthReqInfo.clientId) { logWarn("Missing clientId in OAuth state", { loggerScope: ["cloudflare", "oauth", "callback"], }); return c.text("Invalid state", 400); } // Validate redirectUri is a valid URL if (!oauthReqInfo.redirectUri) { logWarn("Missing redirectUri in OAuth state", { loggerScope: ["cloudflare", "oauth", "callback"], }); return c.text("Authorization failed: No redirect URL provided", 400); } try { new URL(oauthReqInfo.redirectUri); } catch (err) { logWarn(`Invalid redirectUri in OAuth state: ${oauthReqInfo.redirectUri}`, { loggerScope: ["cloudflare", "oauth", "callback"], extra: { error: String(err) }, }); return c.text("Authorization failed: Invalid redirect URL", 400); } // because we share a clientId with the upstream provider, we need to ensure that the // downstream client has been approved by the end-user (e.g. for a new client) // https://github.com/modelcontextprotocol/modelcontextprotocol/discussions/265 const isApproved = await clientIdAlreadyApproved( c.req.raw, oauthReqInfo.clientId, c.env.COOKIE_SECRET, ); if (!isApproved) { return c.text("Authorization failed: Client not approved", 403); } // Validate redirectUri is registered for this client try { const client = await c.env.OAUTH_PROVIDER.lookupClient( oauthReqInfo.clientId, ); const uriIsAllowed = Array.isArray(client?.redirectUris) && client.redirectUris.includes(oauthReqInfo.redirectUri); if (!uriIsAllowed) { logWarn("Redirect URI not registered for client on callback", { loggerScope: ["cloudflare", "oauth", "callback"], extra: { clientId: oauthReqInfo.clientId, redirectUri: oauthReqInfo.redirectUri, }, }); return c.text("Authorization failed: Invalid redirect URL", 400); } } catch (lookupErr) { logWarn("Failed to validate client redirect URI on callback", { loggerScope: ["cloudflare", "oauth", "callback"], extra: { error: String(lookupErr) }, }); return c.text("Authorization failed: Invalid redirect URL", 400); } // Exchange the code for an access token // Note: redirect_uri must match the one used in the authorization request // This is the Sentry callback URL, not the downstream MCP client's redirect URI const sentryCallbackUrl = new URL("/oauth/callback", c.req.url).href; const [payload, errResponse] = await exchangeCodeForAccessToken({ upstream_url: new URL( SENTRY_TOKEN_URL, `https://${c.env.SENTRY_HOST || "sentry.io"}`, ).href, client_id: c.env.SENTRY_CLIENT_ID, client_secret: c.env.SENTRY_CLIENT_SECRET, code: c.req.query("code"), redirect_uri: sentryCallbackUrl, }); if (errResponse) return errResponse; // Parse and validate granted skills first const { valid: validSkills, invalid: invalidSkills } = parseSkills( oauthReqInfo.skills, ); // Log warning for any invalid skill names if (invalidSkills.length > 0) { logWarn("OAuth callback received invalid skill names", { loggerScope: ["cloudflare", "oauth", "callback"], extra: { clientId: oauthReqInfo.clientId, invalidSkills, }, }); } // Validate that at least one valid skill is granted if (validSkills.size === 0) { logWarn("OAuth authorization rejected: No valid skills selected", { loggerScope: ["cloudflare", "oauth", "callback"], extra: { clientId: oauthReqInfo.clientId, receivedSkills: oauthReqInfo.skills, }, }); return c.text( "Authorization failed: You must select at least one valid permission to continue.", 400, ); } // Calculate Sentry API scopes from validated skills const grantedScopes = await getScopesForSkills(validSkills); // Convert valid skills Set to array for OAuth props const grantedSkills = Array.from(validSkills); // Return back to the MCP client a new token const { redirectTo } = await c.env.OAUTH_PROVIDER.completeAuthorization({ request: oauthReqInfo, userId: payload.user.id, metadata: { label: payload.user.name, }, scope: oauthReqInfo.scope, // Props are available via ExecutionContext.props in the MCP handler props: { // OAuth standard fields id: payload.user.id, // Sentry-specific fields accessToken: payload.access_token, refreshToken: payload.refresh_token, // Cache upstream expiry so future refresh grants can avoid // unnecessary upstream refresh calls when still valid accessTokenExpiresAt: Date.now() + payload.expires_in * 1000, clientId: oauthReqInfo.clientId, scope: oauthReqInfo.scope.join(" "), // Scopes derived from skills - for backward compatibility with old MCP clients // that don't support grantedSkills and only understand grantedScopes grantedScopes: Array.from(grantedScopes), grantedSkills, // Primary authorization method // Note: constraints are NOT included here - they're extracted per-request from URL // Note: sentryHost and mcpUrl come from env, not OAuth props } as WorkerProps, }); // Use manual redirect instead of Response.redirect() to allow middleware to add headers return c.redirect(redirectTo); });