performance check: findings for azd-copilot

[jongio]

performance check

• FindCopilotCLI() is called twice per invocation on the hot path - once by IsCopilotInstalled() and again inside Launch() - causing a redundant blocking npm config get prefix subprocess call on Windows whenever npm_config_prefix env var is absent (adds ~300-500ms startup latency). Fix: cache the result in a package-level variable with sync.Once, or return the found path from IsCopilotInstalled() so Launch() can reuse it.
• assets.ListSkills() is called multiple times on every interactive startup with no caching: once in newRootCmd() via SkillCount(), and again in printBanner() - each call walks the embedded FS and parses YAML frontmatter for all ~30 skills from scratch. Same pattern applies to ListAgents(). Fix: cache the result with sync.Once at the package level since the embedded FS is immutable at runtime.
• GetSkill(name) always calls ListSkills() to do a linear O(n) scan across all skills, causing full embedded-FS traversal and YAML parsing for every single-skill lookup. Fix: build a map[string]*SkillInfo once in a sync.Once initializer and use it for O(1) lookups.
• The checkpoint index.json is read from disk independently by every checkpoint operation (Get, ListByType, Delete, KeepLatest, GetProjectFiles, SaveWithOptions), with no in-process cache. Each SaveWithOptions call reads the full index, appends one entry, and rewrites the entire file - making checkpoint saves O(n) in the number of checkpoints. Fix: add a session-lifetime in-memory cache for the index, invalidated on write.

Automated analysis - 4 finding(s)