Optimize Merge Queue with Concurrency and Failure Notifications (#256)

- **Add concurrency to all workflows** - Cancel in-progress runs when
new commits arrive
- **Protect test summaries from cancellation** - Prevent false failures
when workflows are cancelled
- **Add merge queue failure notifications** - Post PR comment with
failed job details when ejected from queue
- **Add Lemonade Server smoke test** - Quick validation before full
integration tests

## Changes

### Concurrency
All workflows now include:
```yaml
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
```

### Cancellation Protection
Test summary jobs use robust `if` conditions to handle cancellation
gracefully:
```yaml
if: >-
  ${{ always() && !cancelled() &&
      needs.job1.result != 'cancelled' &&
      needs.job2.result != 'cancelled' }}
```

### Merge Queue Notification
New `merge-queue-notify.yml` workflow:
- Triggers on workflow completion for merge queue runs
- Extracts PR number from merge queue branch name
- Posts comment with failed jobs and direct links to logs

### Lemonade Smoke Test
New `test_lemonade_server.yml` workflow:
- Validates health endpoint returns `context_size`
- Tests basic completion endpoint
- Runs before Windows/Linux integration tests

### Reusable Start-Lemonade Action
New `.github/actions/start-lemonade/` composite action:
- Cross-platform (Windows/Linux)
- Configurable model, port, context size
- Sets UTF-8 encoding automatically

## Test Plan

- [x] Verify concurrency cancels old runs on new push
- [x] Verify test summaries pass when some jobs are skipped
- [ ] Trigger merge queue failure and verify PR comment appears
- [x] Verify Lemonade smoke test runs before integration tests

- Closes #261

---------

Co-authored-by: kovtcharov-amd <kalin.ovtcharov@amd.com>

Author: kovtcharov

.github/workflows/docs.yml

@@ -13,6 +13,11 @@ on:
       - 'docs/**'
       - '.github/workflows/docs.yml'
 
+# Cancel in-progress runs when a new run is triggered
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   validate:
     runs-on: ubuntu-latest

.github/workflows/lint.yml

@@ -18,6 +18,11 @@ on:
   merge_group:
   workflow_dispatch:
 
+# Cancel in-progress runs when a new run is triggered
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 

.github/workflows/merge-queue-notify.yml

@@ -0,0 +1,98 @@
+# Copyright(C) 2025-2026 Advanced Micro Devices, Inc. All rights reserved.
+# SPDX-License-Identifier: MIT
+
+# Notifies PR authors when their PR fails in the merge queue
+# Watches for workflow completions triggered by merge_group events
+
+name: Merge Queue Failure Notification
+
+on:
+  workflow_run:
+    workflows:
+      - "GAIA CLI Tests (All Platforms)"
+      - "Code Quality (Lint)"
+      - "Unit Tests"
+    types:
+      - completed
+
+permissions:
+  contents: read
+  pull-requests: write
+  actions: read
+
+jobs:
+  notify-on-failure:
+    name: Notify on Merge Queue Failure
+    runs-on: ubuntu-latest
+    # Only run if the triggering workflow was from a merge_group and failed
+    if: >
+      github.event.workflow_run.event == 'merge_group' &&
+      github.event.workflow_run.conclusion == 'failure'
+    steps:
+      - name: Post failure comment to PR
+        uses: actions/github-script@v7
+        with:
+          script: |
+            // Extract PR number from merge queue branch name (e.g., gh-readonly-queue/main/pr-254-...)
+            const headBranch = context.payload.workflow_run.head_branch || '';
+            const prMatch = headBranch.match(/pr-(\d+)/);
+
+            if (!prMatch) {
+              console.log('Could not extract PR number from branch:', headBranch);
+              console.log('This may not be a merge queue run');
+              return;
+            }
+
+            const prNumber = parseInt(prMatch[1], 10);
+            const workflowRun = context.payload.workflow_run;
+            const runUrl = workflowRun.html_url;
+            const workflowName = workflowRun.name;
+
+            // Get the failed jobs for more detail
+            const { data: jobs } = await github.rest.actions.listJobsForWorkflowRun({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              run_id: workflowRun.id,
+            });
+
+            const failedJobs = jobs.jobs.filter(job => job.conclusion === 'failure');
+            const failedJobsList = failedJobs.length > 0
+              ? failedJobs.map(job => `  - [${job.name}](${job.html_url})`).join('\n')
+              : '  - Check workflow run for details';
+
+            const body = `## Merge Queue Failure
+
+Your PR was removed from the merge queue due to test failures in **${workflowName}**.
+
+**Failed jobs:**
+${failedJobsList}
+
+**Full workflow run:** [View logs](${runUrl})
+
+<sub>This comment was automatically generated.</sub>`;
+
+            // Check if we already posted a comment for this run to avoid duplicates
+            const { data: comments } = await github.rest.issues.listComments({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: prNumber,
+            });
+
+            const existingComment = comments.find(c =>
+              c.body.includes('Merge Queue Failure') &&
+              c.body.includes(runUrl)
+            );
+
+            if (existingComment) {
+              console.log('Comment already exists for this run, skipping');
+              return;
+            }
+
+            await github.rest.issues.createComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: prNumber,
+              body: body,
+            });
+
+            console.log(`Posted failure notification to PR #${prNumber}`);

.github/workflows/test_agent_mcp_server.yml

@@ -15,6 +15,11 @@ on:
   merge_group:
   workflow_dispatch:
 
+# Cancel in-progress runs when a new run is triggered
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   test-mcp-agent:
     name: Test MCPAgent (${{ matrix.os }})
@@ -106,7 +111,10 @@ jobs:
     name: Test Summary
     needs: test-mcp-agent
     runs-on: ubuntu-latest
-    if: always()
+    # Run always except when workflow or dependency is cancelled
+    if: >-
+      ${{ always() && !cancelled() &&
+          needs.test-mcp-agent.result != 'cancelled' }}
     permissions: {}
 
     steps:

.github/workflows/test_api.yml

@@ -16,6 +16,11 @@ on:
   merge_group:
   workflow_dispatch:
 
+# Cancel in-progress runs when a new run is triggered
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 

.github/workflows/test_chat_agent.yml

@@ -16,6 +16,11 @@ on:
   merge_group:
   workflow_dispatch:
 
+# Cancel in-progress runs when a new run is triggered
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 

.github/workflows/test_chat_sdk.yml

@@ -24,6 +24,11 @@ on:
   merge_group:
   workflow_dispatch:
 
+# Cancel in-progress runs when a new run is triggered
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 

.github/workflows/test_code_agent.yml

@@ -16,6 +16,11 @@ on:
   merge_group:
   workflow_dispatch:
 
+# Cancel in-progress runs when a new run is triggered
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 

.github/workflows/test_electron.yml

@@ -13,6 +13,11 @@ on:
   merge_group:
   workflow_dispatch:
 
+# Cancel in-progress runs when a new run is triggered
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
   pull-requests: write

.github/workflows/test_embeddings.yml

@@ -13,6 +13,11 @@ on:
   merge_group:
   workflow_dispatch:
 
+# Cancel in-progress runs when a new run is triggered
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read