Sync Xcode Project Guidance

Sync Xcode Project Guidance

SwiftData And SwiftUI Rule

When a task combines SwiftData with SwiftUI, keep SwiftData directly coupled to SwiftUI through Apple's data-driven path: modelContainer, environment modelContext, @Query, SwiftData model objects, and bindings. Do not add repositories, stores, service layers, DTO mirrors, view-model caches, wrapper objects, or other abstraction layers between SwiftData and SwiftUI. If this skill is not the right owner for SwiftData-backed SwiftUI work, hand off to apple-dev-skills:swiftui-app-architecture-workflow instead of inventing an intermediate data layer.

Purpose

Bring an existing Xcode app repository up to the expected guidance baseline without overloading the main Xcode execution skill. This skill owns repo-guidance alignment for existing Apple app repos, including deterministic AGENTS.md creation or bounded section append behavior, and runs maintain-project-repo with the xcode-app profile alongside that guidance. scripts/run_workflow.py is the runtime entrypoint, and scripts/sync_xcode_project_guidance.py applies the current sync behavior.

Companion Plugin Requirement

This skill can be discovered from a standalone apple-dev-skills install, but its mutating guidance-sync path refreshes repo-maintenance files through the companion productivity-skills plugin. Before giving filesystem-level fallback instructions, first check the skills exposed in the current Codex session and use the harness-discovered productivity-skills:maintain-project-repo workflow when it is available. If the companion skill is not exposed, tell the user to add the socket marketplace with codex plugin marketplace add gaelic-ghost/socket, then install the relevant plugins from Codex's plugin directory so future sessions expose both apple-dev-skills and productivity-skills.

When To Use

• Use this skill when an existing macOS, iOS, or iPadOS app repo needs AGENTS.md added, refreshed, or merged with the current Xcode workflow baseline.
• Use this skill when the repository already has an .xcodeproj or .xcworkspace and the user wants project guidance, onboarding rules, or workflow policy brought up to date.
• Use this skill when the user wants the repo guidance for the current narrower Xcode execution skills to be made explicit in the repo itself.
• Do not use this skill for new-project creation from nothing.
• Do not use this skill for ordinary build, test, run, diagnostics, docs lookup, or mutation work inside an existing Xcode project.
• Do not use this skill for plain Swift packages, libraries, or tools that are not native Apple apps.
• Recommend bootstrap-xcode-app-project when the repo does not exist yet.
• Recommend xcode-build-run-workflow when the task is active Xcode execution, diagnostics, docs lookup, previews, file-membership follow-through, or mutation work inside an existing Xcode project.
• Recommend xcode-testing-workflow when the task is primarily about Swift Testing, XCTest, XCUITest, .xctestplan, or test diagnosis inside an existing Xcode project.
• Recommend sync-swift-package-guidance when the repo is a plain Swift package instead of an Xcode app project.
• After updating this plugin's Xcode-policy surfaces, recommend rerunning sync-xcode-project-guidance in downstream repos so their AGENTS.md and maintain-project-repo output stay aligned.
• For maintainer notes about this repository itself, say plainly that the repo exports from top-level skills/ today and does not ship repo-local installer workflows.

Single-Path Workflow

1. Collect the required inputs:

• repo_root
• optional workspace_path
• optional skip_validation
• optional dry_run

1. Classify the request as existing Xcode app-repo guidance sync before continuing:

• continue only when the repo already contains an .xcodeproj or .xcworkspace
• stop if the request is really new-project bootstrap or SwiftPM-only guidance sync

1. Apply the Apple docs gate before shaping workflow guidance:

• read the relevant Apple documentation first
• use Xcode MCP DocumentationSearch or Xcode-local documentation first for Apple-owned SDK, framework, lifecycle, and Xcode project behavior
• use Dash MCP or Dash HTTP next when installed local docsets are a better fit
• use open source Swift project repositories, generated DocC, or release notes when the relevant Swift package or tool is open source and available there
• use official Apple web docs only when the page content is actually readable through a capable source; generic no-JS web search/open results, snippets, metadata shells, or bare URLs are not enough
• state the documented workflow boundary being relied on before proposing repo guidance changes
• current documented anchors for this workflow include:
• Apple's Xcode project-creation guidance: Creating an Xcode project for an app
• SwiftUI app lifecycle guidance through the App protocol: App
• scene composition guidance through Scene and WindowGroup: Scene and WindowGroup
• if the docs and the current guidance template conflict, stop and report that conflict
• if no relevant Apple docs can be found, say that explicitly before proceeding

1. Apply the shared Xcode-project policy before making repo-guidance changes:

• apply the detailed local policy in references/snippets/apple-xcode-project-core.md
• preserve its simplicity-first Swift, SwiftUI, Xcode-managed project, XcodeGen-backed project, test-plan, file-membership, tracked .pbxproj commit, and Debug/Release guidance

1. Run scripts/run_workflow.py to normalize inputs, detect whether the repo is really Xcode-managed, and shape the sync plan.
2. Apply the sync path:

• if AGENTS.md is missing, copy assets/AGENTS.md
• if AGENTS.md exists and already contains the managed section, keep the file unchanged
• if AGENTS.md exists but lacks the managed section, append assets/append-section.md as a bounded section

1. Validate the synced repo guidance:

• verify AGENTS.md exists
• verify the synced file mentions xcode-build-run-workflow and xcode-testing-workflow
• verify the synced file preserves the no-direct-.pbxproj rule and the tracked .pbxproj stage-and-commit rule
• verify the synced file preserves the XcodeGen source-of-truth rule for repos that use generated projects

1. Refresh maintain-project-repo:

• refresh scripts/repo-maintenance/
• refresh .github/workflows/validate-repo-maintenance.yml
• preserve repo-specific extra scripts that are not part of the managed file set

1. Verify the synced maintenance guidance still points at the expected maintainer files:

• .swiftformat
• scripts/repo-maintenance/hooks/pre-commit.sample
• scripts/repo-maintenance/validate-all.sh
• scripts/repo-maintenance/sync-shared.sh
• scripts/repo-maintenance/release.sh
• protected branches, when configured, require the GitHub Actions check context validate rather than Validate Repo Maintenance / validate
• when a GitHub remote exists, route repository settings audit or mutation

through productivity-skills:maintain-github-repository

1. Hand off ongoing engineering work cleanly:

• recommend xcode-build-run-workflow or xcode-testing-workflow for active Xcode collaboration after the repo guidance is aligned
• recommend bootstrap-xcode-app-project only when the user actually needs a fresh repo instead of guidance sync

Inputs

• repo_root: optional absolute or relative path to the repository root; defaults to .
• workspace_path: optional path used only to improve Xcode-project discovery when repo-root detection is ambiguous
• skip_validation: optional flag to skip post-sync file validation
• dry_run: optional flag to emit the planned contract without writing files
• Defaults:
• runtime entrypoint: executable scripts/run_workflow.py
• repo_root=. when omitted
• writeMode=sync-if-needed
• validation runs unless --skip-validation is passed
• successful mutating runs install .codex/environments/xcode-project.toml from templates/codex-local-environments/xcode-project.toml when missing, replace SCHEME_NAME with the workspace or project stem, leave matching files unchanged, and preserve customized existing files
• successful mutating runs refresh maintain-project-repo output in place

Outputs

• status
• success: guidance sync completed or was already satisfied
• blocked: prerequisites, repo classification, or sync policy prevented completion
• failed: the sync path started but did not complete successfully
• path_type
• primary: the documented sync path completed
• fallback: a non-mutating guided result was returned
• output
• resolved repo root
• detected workspace or project markers
• AGENTS.md path
• actions applied or planned
• installed or preserved .codex/environments/xcode-project.toml
• refreshed maintain-project-repo paths
• validation result
• one concise next step or handoff

Guards and Stop Conditions

• Stop with blocked if the repo root cannot be resolved.
• Stop with blocked if the repo does not contain an .xcodeproj or .xcworkspace.
• Stop with blocked if the repo appears to be a SwiftPM-only package without Xcode-managed app markers.
• Stop with blocked if the chosen writeMode does not allow the mutation the repo still needs, such as creating a missing AGENTS.md or appending the bounded Xcode guidance section.
• Stop with blocked if the target AGENTS.md path exists but is not a regular file.
• Fail with a clear message if the Codex local environment template is missing or the target .codex/environments/xcode-project.toml path exists but is not a regular file.

Fallbacks and Handoffs

• The only current fallback is a non-mutating dry-run or guided result that explains what the sync would do.
• After a successful sync, hand off ongoing build, run, diagnostics, preview, and mutation work to xcode-build-run-workflow.
• After a successful sync, hand off ongoing test execution and test diagnosis work to xcode-testing-workflow.
• After a successful sync, use scripts/repo-maintenance/validate-all.sh for local maintainer validation and scripts/repo-maintenance/release.sh --mode standard --version vX.Y.Z from a feature branch or worktree for protected-main releases.
• After a successful sync, configure protected branches to require validate for the managed repo-maintenance workflow; GitHub exposes that job check context directly rather than the workflow title plus job string.
• When a GitHub remote exists, use productivity-skills:maintain-github-repository

to audit repository features, merge modes, security automation, sign-off policy, and branch protection without changing visibility implicitly.

• Recommend bootstrap-xcode-app-project when the repository still needs to be created from scratch.
• Recommend sync-swift-package-guidance when the repo is a plain Swift package rather than an Xcode app project.

Codex Subagent Fit

When the user explicitly asks for subagents, swift-steward, review-packet planning, or asks to keep working while broad Xcode repo-maintenance discovery happens in parallel, use the swift-steward custom-agent role for read-heavy discovery before this skill applies guidance sync.

Good swift-steward jobs for this skill:

• classify the project shape and flag ambiguous SwiftPM/Xcode boundaries
• inspect AGENTS.md, README, CONTRIBUTING, ROADMAP, Xcode project/workspace markers, .swiftformat, .swiftlint.yml, and scripts/repo-maintenance/
• compare current repo guidance against this skill's current Xcode baseline
• return a review packet with proposed patch set, validation handoff, affected files, and blockers

Keep apply-mode edits in the main thread. The steward may return proposed patch-set entries, but the main agent should review them with the user before saving, editing, or applying any edits.

Customization

• Use references/customization-flow.md.
• scripts/customization_config.py stores and reports customization state.
• scripts/run_workflow.py loads runtime-safe defaults from customization state before invoking the supported sync path.
• The current runtime-enforced customization surface is one writeMode knob that controls whether the workflow may create missing AGENTS.md, append the bounded Xcode section, or stay report-only.
• Run the Python wrapper and customization entrypoints through uv, because they rely on inline PyYAML script metadata rather than a repo-global Python environment.
• In consuming repos, the supported path is uv run scripts/run_workflow.py ... and uv run scripts/customization_config.py ...; do not assume plain python or python3 will have the needed YAML dependency installed.

References

Workflow References

• references/project-detection.md

Contract References

• references/automation-prompts.md
• references/customization-flow.md

Support References

• assets/AGENTS.md
• assets/append-section.md
• Recommend references/snippets/apple-xcode-project-core.md when an existing Xcode repo needs the reusable baseline policy content in a human-reviewable form.
• references/snippets/apple-xcode-project-core.md
• templates/codex-local-environments/xcode-project.toml

Script Inventory

• scripts/run_workflow.py
• scripts/sync_xcode_project_guidance.py
• scripts/customization_config.py

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: gaelic-ghost
• Source: gaelic-ghost/socket
• License: Apache-2.0

Install and usage instructions live in the source repository linked above.