fix(databricks-mcp): support mcp 2.x and drop the temporary <2.0.0 pin - #458
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PR databricks#457 pinned `mcp>=1.13.0,<2.0.0` as a stopgap because mcp 2.0.0 removed the legacy `streamablehttp_client` symbol (and reworked the transport/session and auth APIs), which broke `databricks-mcp` at import time on fresh installs that resolved to mcp 2.x. This is the proper fix: make the code compatible with mcp 2.x while staying backward compatible with mcp 1.x, then remove the install-time cap so future mcp majors are not blocked at resolve time. ## Summary - Detect the installed mcp major (`_MCP_V2 = try: from mcp import Client`) and route both code paths through a single `_open_mcp_session()` helper: - mcp 2.x: attach `DatabricksOAuthClientProvider` (now an `httpx2.Auth`) to an `httpx2.AsyncClient` handed to `streamable_http_client(url, http_client=...)`, wrapped in `mcp.Client` (which performs the initialize handshake itself). - mcp 1.x: `streamablehttp_client(url, auth=...)` + `ClientSession` + explicit `initialize()`, as before. - `oauth_provider.py`: no code change needed (subclassing `OAuthClientProvider` picks up `httpx2.Auth` automatically on v2); docstring updated to show both usage patterns. - Widen the dependency to `mcp>=1.13.0` (no upper bound). - Bump `databricks-mcp` to 0.9.2. - Update tests for mcp 2.x API renames while keeping them runnable on 1.x: build `Tool` via `model_validate({"inputSchema": ...})` (2.x renamed the field to `input_schema`), import `MCPError` (renamed from `McpError`) with a fallback, and patch the version-agnostic `_open_mcp_session`. The integration-test `raw_mcp_session` helper is now version-aware. ## Test Plan - `uv run pytest tests/unit_tests/` — 113 passed against mcp 1.24.0. - Same suite — 113 passed against mcp 2.0.0. - `ty check` (ty 0.0.23) clean against mcp 2.0.0; `ruff check` / `ruff format` clean. - Verified the real v2 wiring (`httpx2.AsyncClient` + `streamable_http_client` + `Client`) constructs and reaches the transport layer end-to-end. ## Type of change - [x] Bug fix (non-breaking change which fixes an issue) ## Changelog databricks-mcp is now compatible with mcp 2.x (and remains compatible with mcp 1.x). Signed-off-by: Zeyi (Rice) Fan <zeyi.f@databricks.com>
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Summary
PR #457 pinned
mcp>=1.13.0,<2.0.0as a stopgap because mcp 2.0.0 removed the legacystreamablehttp_clientsymbol (and reworked the transport/session and auth APIs), which brokedatabricks-mcpat import time on fresh installs that resolved to mcp 2.x.This is the proper fix: make
databricks-mcpcompatible with mcp 2.x while remaining backward compatible with mcp 1.x, then drop the install-time cap so future mcp majors are not blocked at resolve time._MCP_V2 = try: from mcp import Client) and route both code paths through a single_open_mcp_session()helper:DatabricksOAuthClientProvider(now anhttpx2.Auth) to anhttpx2.AsyncClienthanded tostreamable_http_client(url, http_client=...), wrapped inmcp.Client(which performs the initialize handshake itself).streamablehttp_client(url, auth=...)+ClientSession+ explicitinitialize(), as before.oauth_provider.py: no code change needed (subclassingOAuthClientProviderpicks uphttpx2.Authautomatically on v2); docstring updated to show both usage patterns.mcp>=1.13.0(no upper bound).databricks-mcpto0.9.2._open_mcp_session; make the integration-testraw_mcp_sessionhelper version-aware.Test Plan
uv run pytest tests/unit_tests/— 113 passed against mcp 1.24.0.httpx2.AsyncClient+streamable_http_client+Client) constructs and reaches the transport layer end-to-end.ruff check/ruff formatclean.Type of change
Changelog
databricks-mcp is now compatible with mcp 2.x (and remains compatible with mcp 1.x).