[erichare]

What this PR does:

Defers MCP context setup and handles request, schema, and provider setup failures at one shared boundary. Known non-security Data API errors keep their codes and messages, while unexpected setup failures return a generic error. HTTP authentication, protocol, cancellation, and processor failures keep their existing handling. A token the database rejects after HTTP authentication returns UNAUTHENTICATED_REQUEST as a tool error, as collection commands already did on main.

Tool results keep empty text content, so the tests check structuredContent and _meta.

Which issue(s) this PR fixes:

Fixes #2628. OAuth admission remains in #2642.

Verification

40 focused tests passed with 0 failures, 0 errors, and 0 skips at e06f92466, this PR's commit in the rebuilt stack. The format check found 0 non-complying files out of 1,204. The new integration test, rejectedTokenReturnsAnApplicationErrorThenAValidCallSucceeds, did not run locally: the amd64 DSE container ran out of memory under emulation on this arm64 machine. Both CI integration jobs run McpSetupErrorsIntegrationTest on this push. CI also runs the unit suite.

JAVA_HOME=/Library/Java/JavaVirtualMachines/graalvm-21.jdk/Contents/Home ./mvnw -B -ntp clean com.spotify.fmt:fmt-maven-plugin:check test -DskipITs -Dxml-format.skip=true -Dsurefire.failIfNoSpecifiedTests=false -Dquarkus.http.test-port=19089 '-Dtest=McpSetupErrorsTest,McpResourceTest,CommandResultToToolResponseTest'

Manual client checks were not run.

Checklist

• Changes manually tested
• Automated Tests added/updated
• Documentation added/updated
• CLA Signed: DataStax CLA

MCP stack

Merges bottom up; row 1 is the bottom of the stack.

#	PR	Change	Issue
1	#2651	Show accepted update syntax in tool schemas	Fixes #2631
2	#2658	Describe every tool argument	Part of #2604
3	#2645	Close the command context after each call	Part of #2629
4	#2653	Return useful errors when setup fails	Fixes #2628
5	#2648	Keep payloads and credentials out of logs	Fixes #2635
6	#2649	Describe side effects and retry behavior	Fixes #2636
7	#2655	Validate commands like the HTTP API	Fixes #2632
8	#2656	Test request isolation, document tracing	Refs #2629
9	#2657	Reject unapproved browser origins	Part of #2630
10	#2659	Serve only protocol 2026-07-28	Part of #2625, #2626
11	#2669	Add opt-in OAuth authentication	Refs #2642, #2643

[github-actions]

📈 Unit Test Coverage Delta vs Main Branch

Metric	Value
Main Branch	56.74%
This PR	57.31%
Delta	🟢 +0.57%
✅ Coverage improved!

[github-actions]

Unit Test Coverage Report

Overall Project	57.31% -0.04%	🍏
Files changed	86.17%	🍏

File	Coverage
McpResource.java	90.03% -9.97%	🍏

[github-actions]

📈 Integration Test Coverage Delta vs Main Branch (dse69-it)

Metric	Value
Main Branch	72.98%
This PR	72.99%
Delta	🟢 +0.01%
✅ Coverage improved!

[github-actions]

Integration Test Coverage Report (dse69-it)

Overall Project	72.99% -0.05%	🍏
Files changed	81.56%	🍏

File	Coverage
McpResource.java	85.03% -13.2%	🍏

[github-actions]

📈 Integration Test Coverage Delta vs Main Branch (hcd-it)

Metric	Value
Main Branch	74.33%
This PR	74.33%
Delta	🟢 +0.00%
✅ Coverage improved!

[github-actions]

Integration Test Coverage Report (hcd-it)

Overall Project	74.33% -0.05%	🍏
Files changed	81.56%	🍏

File	Coverage
McpResource.java	85.03% -13.2%	🍏