Cherry-pick #16306 to dev: generate DT add-MCP action inline instead of v4 modify front door

[Copilot]

Synchronizes PR #16306 (fix(fx-core): generate DT add-MCP action inline instead of v4 modify front door) from release/6.12 to dev. Previously, with DT on, atk add action --api-plugin-type mcp routed through the v4 modify front door, producing an incomplete oauth/register in m365agents.yml and coupling DT to TEAMSFX_V4_ENABLED.

Changes (cherry-picked)

• Inline DT add-MCP (FxCore.declarativeAgent.ts): DT-on writes the URL-only ai-plugin.json and wires oauth/register / dcr/register via the shared injector directly in core.addPlugin, independent of TEAMSFX_V4_ENABLED. The v4 add-mcp-server modify template is untouched.
• URL-derived naming: oauth/register name / registrationId derive from the MCP server URL (shared with the create flow), making re-adds idempotent (one registration per server).
• Best-effort auth resolution: endpoint resolution and yml injection are split into two steps, so a failed auth-metadata probe (unreachable server / no resource_metadata) still writes the registration action for the developer to complete.
• Feature flag: TEAMSFX_MCP_FOR_DA_DT defaults on; FeatureFlagManager.listEnabled now honours default-on flags.
• CLI: regenerated AddPluginInputs / AddPluginOptions; added MCP no-auth / with-auth / edge-case e2e coverage.

Conflict resolution notes

• FxCore.declarativeAgent.ts conflicted only because dev had already dropped a callCoreMethod: line from the old v4-dispatch block that this change deletes wholesale; the resolved file is byte-identical to the source commit with no dev-specific change lost.
• Commit 3 of the source PR (test-infra) is intentionally omitted. It makes template-version tests version-independent for the release branch's rc versioning and the version-parsing useLocalTemplate logic — both refactored away on dev, which now uses a config-flag useLocalTemplate and a stable version. dev's utils.test.ts / generator.test.ts already pass without it, and applying it would target tests dev has removed.

[github-actions]

E2E Test Selection — AI Selected

Why these tests: The fx-core changes target declarativeAgent logic (FxCore.declarativeAgent.ts, AddPluginInputs/Options) and feature flags, so all declarativeAgent/* tests are included; the three MCP test files are returned directly as changed e2e tests (rule 7); feature/multienv covers the featureFlags.ts change impact.

Cases selected (14):

• ./declarativeAgent/DeclarativeAgentBasic.tests.ts
• ./declarativeAgent/DeclarativeAgentWithApiKeyAuth.tests.ts
• ./declarativeAgent/DeclarativeAgentWithOAuth.tests.ts
• ./declarativeAgent/DeclarativeAgentInvalidManifestShape.tests.ts
• ./declarativeAgent/DeclarativeAgentWithEntra.tests.ts
• ./declarativeAgent/DeclarativeAgentWithNoneAuth.tests.ts
• ./declarativeAgent/typespec/typespec.withoutAction.tests.ts
• ./declarativeAgent/typespec/typespec.withAction.tests.ts
• ./declarativeAgent/addKnowledge/AddWebSearchByAll.tests.ts
• ./declarativeAgent/addKnowledge/AddWebSearchByUrl.tests.ts
• ./declarativeAgent/mcp/DeclarativeAgentMCPNoAuth.tests.ts
• ./declarativeAgent/mcp/DeclarativeAgentMCPWithAuth.tests.ts
• ./declarativeAgent/mcp/DeclarativeAgentMCPAuthEdgeCases.tests.ts
• ./feature/multienv.tests.ts

---

View pipeline run

Need to run more tests?

Comment on this PR:

• /e2e-run ./path/to/test.tests.ts — add specific cases to AI selection
• /e2e-run-all — run all e2e cases

Then re-run the workflow.

[codecov]

Codecov Report

❌ Patch coverage is 97.14286% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 87.28%. Comparing base (cac6a2b) to head (d466617).
⚠️ Report is 1 commits behind head on dev.

Files with missing lines	Patch %	Lines
...ckages/fx-core/src/core/FxCore.declarativeAgent.ts	97.05%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev   #16312      +/-   ##
==========================================
+ Coverage   87.26%   87.28%   +0.02%     
==========================================
  Files         631      633       +2     
  Lines       33084    33133      +49     
  Branches     7715     7724       +9     
==========================================
+ Hits        28870    28920      +50     
- Misses       2401     2407       +6     
+ Partials     1813     1806       -7     

Files with missing lines	Coverage Δ
packages/fx-core/src/common/featureFlags.ts	96.92% <100.00%> (ø)
...s/fx-core/src/question/options/AddPluginOptions.ts	100.00% <ø> (ø)
...ckages/fx-core/src/core/FxCore.declarativeAgent.ts	82.40% <97.05%> (+4.02%)	⬆️

... and 12 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[Alive-Fish]

@copilot fix patch coverage

[Copilot]

@copilot fix patch coverage

Fixed patch coverage: added three unit tests to FxCore.declarativeAgent.test.ts covering the previously-uncovered added lines in the DT add-MCP inline flow — the injectMCPAuthActionToYml failure warning path, the addAction error return, and the name_for_human folder-name fallback. All added source lines are now covered.