Daily Breaking Change Analysis - 2026-04-20

[github-actions]

Summary

• Total Breaking Changes: 5
• Severity: CRITICAL
• Commits Analyzed: 1 (8ba1171)
• Status: ⚠️ Requires Immediate Review

Five major breaking changes were introduced in commit 8ba1171 (PR #27372), all tagged with major changeset bumps.

Critical Breaking Changes

Commit	File	Category	Change	Impact
8ba1171	.changeset/minor-rename-app-to-github-app.md	Schema Change	app: field renamed to github-app:	Workflows using app: will fail validation
8ba1171	.changeset/minor-rename-llmgateway-port.md	Schema / Behavior	supportsLLMGateway renamed to llmGatewayPort; port is now mandatory	Engine configs using supportsLLMGateway: true will break; SupportsLLMGateway interface hooks removed
8ba1171	.changeset/minor-decouple-status-comment.md	Behavior Change	Status comment no longer enabled by default	Workflows relying on implicit status comment must add status-comment: true
8ba1171	.changeset/minor-disable-agent-sandbox-only.md	Schema Change	sandbox: false removed; replaced with sandbox.agent: false	Workflows using sandbox: false will fail validation
8ba1171	.changeset/minor-update-mcpg-v0-1-5.md	Behavior Change	MCP Gateway v0.1.5 stricter validation (Docker-only stdio, explicit mount modes, no mounts on HTTP)	Previously valid MCP server configs may now fail validation

Full Code Diff Analysis

Breaking Change 1: app: → github-app: Field Rename

Category: Schema Change — Removing a field from workflow frontmatter schema

Description: The deprecated app: workflow field has been renamed to github-app:. Workflows using the old app: field will fail validation. A codemod is available via gh aw fix.

Migration:

# Before
app:
  id: $\{\{ secrets.APP_ID }}
  private-key: $\{\{ secrets.APP_PRIVATE_KEY }}

# After
github-app:
  id: $\{\{ secrets.APP_ID }}
  private-key: $\{\{ secrets.APP_PRIVATE_KEY }}

---

Breaking Change 2: supportsLLMGateway → llmGatewayPort Rename

Category: Schema / Behavior Change — Field renamed and made mandatory

Description: The supportsLLMGateway engine configuration field has been renamed to llmGatewayPort. The port is now mandatory (previously optional as a boolean toggle). The SupportsLLMGateway interface hooks have been removed entirely.

Migration:

# Before
supportsLLMGateway: true

# After
llmGatewayPort: 8080

---

Breaking Change 3: Status Comment Decoupled

Category: Behavior Change — Default value changed

Description: The status comment (started/completed notification) is no longer implicitly enabled alongside the ai-reaction emoji. Both must now be explicitly enabled. Fixes #15831.

Migration:

# After (must be explicit if needed)
status-comment: true

---

Breaking Change 4: sandbox: false Removed

Category: Schema Change — Removing a field from workflow frontmatter schema

Description: The deprecated top-level sandbox: false option has been removed. Only the agent firewall can be disabled; the MCP gateway stays enabled. Run gh aw fix to auto-migrate.

Migration:

# Before
sandbox: false

# After
sandbox:
  agent: false

---

Breaking Change 5: MCP Gateway v0.1.5 Stricter Validation

Category: Behavior Change — Stricter validation rules

Description: MCP Gateway v0.1.5 introduces three new rules:

• stdio MCP servers must use Docker-only TOML configuration
• Mount configurations must specify explicit mount modes
• HTTP MCP servers must not include mount configurations

Migration:

# Before (non-Docker stdio — now rejected)
mcp:
  servers:
    my-server:
      type: stdio
      command: my-server-binary

# After (Docker-only stdio)
mcp:
  servers:
    my-server:
      type: stdio
      image: my-server-image:latest

All Commits Analyzed

SHA	Message	Files Changed
8ba1171	Upgrade test workflow: release-created trigger, prerelease coverage, and failure conclusion/issue flow (#27372)	1000+ files (full repo snapshot)

Changesets with major bump type found in this commit:

• .changeset/minor-rename-app-to-github-app.md
• .changeset/minor-rename-llmgateway-port.md
• .changeset/minor-decouple-status-comment.md
• .changeset/minor-disable-agent-sandbox-only.md
• .changeset/minor-update-mcpg-v0-1-5.md

Action Checklist

Complete the following items to address these breaking changes:

• Review all breaking changes detected — Verify each change is correctly categorized
• Create a changeset file in .changeset/ directory — The five major changesets are already present; confirm they are included in the next release
• Add migration guidance to changeset — Migration steps are included in each changeset file
• Document breaking changes in CHANGELOG.md — Add entries under "Breaking Changes" section for all five changes above
• Verify backward compatibility was considered — Confirm gh aw fix codemods exist for all applicable changes (confirmed for app: → github-app: and sandbox: false → sandbox.agent: false)

Recommendations

1. Increment major version — Five major changesets are present; the next release must be a major version bump per semver policy.
2. Run gh aw fix — Automated codemods exist for app: → github-app: and sandbox: false → sandbox.agent: false. Communicate this to users.
3. Validate existing workflows — Users should run gh aw compile to discover validation failures before upgrading.
4. MCP server configs — Review and update any HTTP or stdio MCP server configurations to comply with MCP Gateway v0.1.5 rules.

Reference

See scratchpad/breaking-cli-rules.md for the complete breaking change policy.

---

Once all checklist items are complete, close this issue.

References:

• §24674597708

⚠️ Compatibility report by Breaking Change Checker · ● 841.3K · ◷