harness-update_skill

Overview

This skill safely updates a project's Claude Code harness to the latest harness version with automated backups and non-destructive merges. It preserves user customizations, detects template changes, and proposes safe fixes for breaking-change patterns. Use it when you need controlled harness or template updates while keeping project-specific settings intact.

How this skill works

The skill detects the current harness version from .claude-code-harness-version and compares it to the latest release, then runs a content-level check (template-tracker) to find template updates. It creates a timestamped backup, applies non-destructive updates to settings and workflow files (overwriting only when not localized), fixes known breaking-change patterns, and performs post-update verification with syntax checks and a completion report. Skills diffs are detected and proposed rather than applied blindly.

When to use it

• User issues the /harness-update command
• You need to update the harness version or harness templates
• Template updates are available and you want a safe, reversible apply
• You want to fix known harness-related configuration issues (permissions, deprecated keys)
• You need to add new harness features without losing custom settings

Best practices

• Confirm scope before updating: harness/template updates only, not app or dependency updates
• Review proposed skill diffs and localization decisions before applying merges
• Keep incomplete Plans.md tasks and .claude/memory untouched; verify backups first
• Run template-tracker and JSON syntax checks after the update
• Use the provided backup path (.claude-code-harness/backups/{timestamp}/) to restore if needed

Example use cases

• Update a project from an older harness version while preserving custom .claude/settings.json entries
• Apply template fixes that correct permission syntax or deprecated settings
• Detect new skills introduced in the harness and propose adding them to the project
• Merge workflow updates into a localized project with user-confirmed merges
• Create an automatic backup and verification report after performing harness updates