ai-engineering-fluency: Skill for Claude Code

Validate App DB Schema Skill

Validates that the Copilot app's ~/.copilot/data.db still exposes the tables and columns that the extension's session hierarchy feature depends on.

Background

The session hierarchy feature reads parent/child workspace relationships from data.db — a private Copilot app database that is not part of any public API. Its schema can change without notice when the app is updated.

This skill:

1. Checks that the required tables and columns exist
2. Runs an actual data query (today's parent/child links) to confirm reads work end-to-end
3. Reports a clear PASS / FAIL with details so CI or a periodic workflow can surface regressions early

What We Depend On

Table	Required columns
workspace_parent_links	child_workspace_id, parent_workspace_id, creator_session_id, created_at
workspaces	id, session_id, name, updated_at
sessions	id, title, created_at, updated_at

The join that the extension uses (simplified):

SELECT cw.session_id, cw.name, pw.session_id, pw.name
FROM workspace_parent_links l
JOIN workspaces cw ON cw.id = l.child_workspace_id
JOIN workspaces pw ON pw.id = l.parent_workspace_id
WHERE cw.session_id IN (...)
   OR pw.session_id IN (...)

Usage

# Basic validation — exits 0 on pass, 1 on fail
node .github/skills/validate-app-db-schema/validate-schema.js

# Output as JSON (for automated processing)
node .github/skills/validate-app-db-schema/validate-schema.js --json

# Show help
node .github/skills/validate-app-db-schema/validate-schema.js --help

Integration

Add to a periodic GitHub Actions workflow or run manually after a Copilot app update. Example:

- name: Validate data.db schema
  run: node .github/skills/validate-app-db-schema/validate-schema.js --json

Implementation Details

The script reads data.db using sql.js (pure WASM — no native SQLite binaries required). It performs three checks:

1. File exists: ~/.copilot/data.db is present
2. Schema check: PRAGMA table_info(table_name) confirms all required columns exist
3. Live query: Runs the actual JOIN query used by the extension against the last 24h of data