Enable inline sub-agents by default; deprecate features.inline-agents; reject inline-sub-agents: false

[Copilot]

✨ Enhancement

Inline sub-agents now run as default behavior instead of an opt-in feature flag. This change deprecates the legacy features.inline-agents switch and makes explicit disablement via inline-sub-agents: false a compile-time error.

• Default behavior shift

  • Inline sub-agent extraction/restore now assumes always-enabled behavior.
  • Removed experimental warning semantics tied to inline sub-agents.

• Deprecation + migration

  • features.inline-agents remains accepted as deprecated/no-op for compatibility.
  • Updated codemod metadata to support future cleanup of deprecated flag usage (IntroducedIn: 1.0.0).

• Top-level frontmatter enforcement

  • Added typed/frontmatter support for top-level inline-sub-agents.
  • If inline-sub-agents: false is present, compilation now fails with a clear error.

• Spec/docs alignment

  • Extended schema to document inline-sub-agents deprecation semantics.
  • Updated docs to reflect:
    • inline sub-agents are default-on,
    • features.inline-agents is deprecated,
    • inline-sub-agents: false is invalid.

---
engine: copilot
inline-sub-agents: false
features:
  inline-agents: true # deprecated/no-op
---

# compile error:
# inline-sub-agents: false is not supported. Inline sub-agents are always enabled.

[pelikhan]

@copilot what is this version number?

[Copilot]

IntroducedIn is the codemod metadata version (when this codemod was introduced). It should be 1.0.0 here, and I fixed it in a01130d.

[Copilot]

Pull request overview

Shifts inline sub-agent handling to be default-on, deprecates the legacy features.inline-agents toggle as a no-op, and makes inline-sub-agents: false a hard compile-time error while updating schema/docs/tests accordingly.

Changes:

• Add typed + raw-frontmatter plumbing for top-level inline-sub-agents, and fail compilation when it is explicitly set to false.
• Remove “experimental feature” warning semantics for inline sub-agents and improve logging.
• Update schema, codemod metadata test, and docs to reflect the new default-on + deprecation behavior.

Show a summary per file

File	Description
pkg/workflow/workflow_builder.go	Reads inline-sub-agents from parsed or raw frontmatter and stores the disable intent in WorkflowData.
pkg/workflow/frontmatter_types.go	Adds InlineSubAgents *bool to typed frontmatter config with deprecation guidance.
pkg/workflow/frontmatter_types_test.go	Adds coverage for parsing inline-sub-agents as a boolean into typed config.
pkg/workflow/frontmatter_serialization.go	Ensures inline-sub-agents round-trips via FrontmatterConfig.ToMap() when explicitly present.
pkg/workflow/compiler_validators.go	Enforces compile-time error when inline-sub-agents: false is set.
pkg/workflow/compiler_validators_test.go	Adds validator test ensuring the new compile-time error is produced.
pkg/workflow/compiler_types.go	Introduces InlineSubAgentsDisabled field on WorkflowData to carry the validation signal.
pkg/workflow/compiler_orchestrator_tools.go	Removes experimental warning emission; logs extracted inline sub-agent count instead.
pkg/parser/schemas/main_workflow_schema.json	Documents inline-sub-agents as deprecated and notes that false triggers a compile error.
pkg/cli/codemod_inline_agents_test.go	Asserts codemod IntroducedIn metadata is set (for future cleanup workflows).
docs/src/content/docs/reference/inline-sub-agents.md	Updates reference to reflect default-on behavior and deprecation/error semantics.
docs/src/content/docs/patterns/data-ops.md	Removes obsolete “enable via features.inline-agents” guidance; clarifies default-on and tool requirement.
.github/aw/subagents.md	Removes experimental-warning documentation and documents compile failure for inline-sub-agents: false.

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• Files reviewed: 13/13 changed files
• Comments generated: 0