<arc_runtime> Arc-owned files live under the Arc install root for full-runtime installs.

Set ${ARC_ROOT} to that root and use ${ARC_ROOT}/... for Arc bundle files such as references/, disciplines/, agents/, templates/, scripts/, and rules/.

Project-local files stay relative to the user's repository. </arc_runtime>

Using Arc

Arc has a broad workflow surface. Use this skill as the small control plane that decides how to route work without loading every workflow into context at once.

Instruction Priority

When instructions conflict, use this order:

1. User instructions in the conversation
2. Project instructions (AGENTS.md, CLAUDE.md, repo docs)
3. Arc skills
4. Default system behavior

The user stays in control. Arc provides process, not authority over explicit user intent.

The Rule

Before substantial work, decide whether an Arc skill clearly applies.

• If the user names an Arc skill, use it.
• If the task clearly matches an Arc workflow, use that skill before acting.
• If the task is small, direct, or outside Arc's workflows, respond normally.

Arc should improve routing, not create ceremony for every trivial request.

Platform Adaptation

<required_reading> Arc skills may mention Claude Code tool names. For platform mappings and equivalents, read:

${ARC_ROOT}/references/platform-tools.md </required_reading>

When a skill says AskUserQuestion, preserve the behavior rather than the literal tool name. In Codex, ask one concise plain-text question at a time unless a structured question tool is actually available in the current mode. Do not narrate tool fallbacks or tell the user that a question tool is unavailable.

Arc Runtime

Arc supports two install classes:

• Full-runtime installs: Claude plugin and Codex installer. These include Arc-owned ${ARC_ROOT}/agents/, ${ARC_ROOT}/references/, ${ARC_ROOT}/disciplines/, ${ARC_ROOT}/templates/, and ${ARC_ROOT}/scripts/.
• Prompt-only installs: skills.sh and similar prompt distributors. These copy SKILL.md files only.

When a workflow needs Arc-owned files, resolve the Arc install root from the loaded skill's location and refer to it as ${ARC_ROOT}. Use ${ARC_ROOT}/... for Arc bundle files, and keep project-local paths such as .ruler/ or rules/ scoped to the user's repository.

If the requested workflow depends on Arc-owned files and the environment only has prompt-only skills, stop early and tell the user to upgrade to the full Claude plugin or Codex installer.

For UI work, keep these roles separate:

• WireText -> low-fidelity wireframes and layout exploration
• Chrome MCP -> preferred rendered-page verification in Claude Code
• agent-browser -> preferred browser automation fallback outside Claude Code
• Playwright -> scripted browser fallback when needed
• Figma MCP -> implementation from real design files

Progressive Disclosure

Do not preload large Arc workflows.

• Start with the smallest relevant skill
• Load reference files only when the active task actually needs them
• Prefer targeted rules and references over broad up-front reading

Workflow Routing

Use these defaults:

• New feature or product thinking -> ideate
• Plan execution -> implement
• Small scoped change -> implement
• Architecture or quality review -> review or audit
• Testing work -> testing
• Production readiness -> letsgo
• Unsure what to do -> go or suggest

Artifact Locations

Arc-owned artifacts live under:

• docs/arc/specs/
• docs/arc/plans/
• docs/arc/archive/
• docs/arc/progress.md

If a workflow references legacy docs/plans/ or docs/progress.md, treat those as compatibility fallbacks while the repo migrates.