[dsghi]

Summary

DevBrain 2.0 replaces the Azure Functions host with a standalone ASP.NET Core MCP host on Azure Container Apps. The endpoint moves from /runtime/webhooks/mcp on the Function App to /mcp on the Container App. Existing Cosmos documents carry over unchanged.

• Add DevBrain.Server, a .NET 10 ASP.NET Core MCP host on ModelContextProtocol.AspNetCore 2.2.0 and the 2026-07-28 MCP specification revision, with a stateless Streamable HTTP transport.
• Extract the shared Cosmos and OAuth/DCR behavior into DevBrain.Core.
• Add Azure Container Apps and ACR infrastructure, managed-identity access, health probes, rate limits, DevBrain.User app-role authorization, and a reprovision-safe azd workflow.
• Retire the Azure Functions host. Remove the DevBrain.Functions project, the Function App and Flex plan, their role assignments and blob containers, the azd api service, and the Functions-only packages, including Microsoft.ApplicationInsights.WorkerService.
• Harden OAuth diagnostics so caller-controlled values can't forge log entries or disclose OAuth secrets.
• Refresh dependencies, migrate the tests to xUnit v3 on Microsoft.Testing.Platform, and make Directory.Build.props the single source of the release version.
• Rewrite the README as a new-tenant runbook: Entra app with the DevBrain.User role, user assignment, provision, redirect URI, deploy, verify, first-run seeding, upgrading from 1.x, and operating notes.

Why

The Azure Functions MCP extension lags the current SDK and protocol behavior, and it doesn't let DevBrain own the MCP authentication challenge. That's why VS Code and GitHub Copilot never started OAuth. The direct ASP.NET Core host provides current protocol support, standards-compliant 401 challenges, and more hosting flexibility.

Deployment notes

• Reuses the existing Cosmos documents and oauth_state containers; no data migration.
• Keeps the dataprotection-keys-v2 key ring and the v2: OAuth key prefix, so live sessions on the current Container Apps deployment survive this change.
• Defaults to zero minimum replicas and doesn't need Redis, Front Door, or a custom domain.
• Retries the first managed-identity Cosmos role assignment during Entra propagation.
• Preserves the deployed private image during later infrastructure-only provisions.
• New OAUTH_REDIRECT_URI output gives the exact /callback URL to register on the Entra app.
• Existing 1.x environments: azd provision is incremental, so it won't delete the old Function App, its plan, or the deploymentpackage and dataprotection-keys containers. Delete them manually once no client uses the old endpoint (README → "Upgrading from 1.x").

Tests

• Renamed DevBrain.Functions.Tests to DevBrain.Core.Tests; both test projects now run on xunit.v3 4.0.1 through Microsoft.Testing.Platform (global.json).
• Moved the RFC 6749/7591/8414/9728 wire-format guards onto the server's OAuth response types.
• Removed the Functions-only McpToolContextAccessor tests and the Functions-vs-server contract parity test.
• Added adversarial regression coverage for authorization, callback, registration, and token requests containing CR/LF injection payloads.

CodeQL disposition

• Fixed 16 actionable log-forging flows by replacing raw caller-controlled OAuth fields with fixed-length SHA-256 fingerprints or bounded structural flags.
• Alerts v1.5.0 — delete, append, chunked-upload primitives + key hygiene #11, feat: v1.6.0 — DCR facade + per-user OAuth, function-key auth removed #12, and Harden refresh token rotation for client retries #20 traced server-generated values reachable only after successful validation, so the reported injection path wasn't exploitable. Those diagnostics were standardized to fingerprints anyway.
• Alert Add refresh token auth diagnostics #21 couldn't forge a log entry because the cleanup key is server-generated base64url data. The raw key and Cosmos exception message were still removed, because some key types contain OAuth secrets.
• Alerts Refresh MCP runtime dependencies #22 and Bump System.Security.Cryptography.Xml from 10.0.8 to 10.0.10 #23 are false positives, and Make OAuth token windows configurable #24 is a post-fix duplicate of Bump System.Security.Cryptography.Xml from 10.0.8 to 10.0.10 #23 after line movement. The conditions require the exact OAuth constants response_type=code and code_challenge_method=S256 before calling a pure authorization-URI builder that receives only configured values and server-generated state/PKCE data. There's no caller-controlled authentication or authorization bypass; the alerts were dismissed with this rationale.

Validation

• dotnet test --solution devbrain.slnx: 157 tests pass across DevBrain.Core.Tests and DevBrain.Server.Tests.
• dotnet build has 0 warnings; az bicep build succeeds; the post-provision hook parses cleanly; the container image builds from src/DevBrain.Server/Dockerfile.
• dotnet list package --outdated / --vulnerable / --deprecated reports every direct reference current and nothing vulnerable or deprecated.
• The Container Apps host is live in production. Managed-identity RBAC is verified, and the health endpoint stays healthy after reprovisioning.
• The unified ChatGPT/Codex Windows app completed OAuth with DevBrain.User, discovered all 12 tools, and read existing shared Cosmos documents.
• VS Code / GitHub Copilot completes OAuth and works end to end, which was blocked on the Functions host.
• Cursor is expected to work (it supports current MCP OAuth) but hasn't been validated.

🤖 Generated with Claude Code