PR #25373: Add verbose skill load timing diagnostics

• Repository: google-gemini/gemini-cli
• Author: jasonmatthewsuhari
• State: open | merged: False
• Link: https://github.com/google-gemini/gemini-cli/pull/25373

Description (problem / solution / changelog)

Tries to address feature request #25315

Summary

Records skill discovery timing and shows it through verbose skill-listing flows. This first pass stays focused on reporting. It does not add client-side caching as suggested in the issue.

What changed

• record per-directory discovery timing and per-skill load timing in the skill loader
• expose that in /skills list verbose
• keep normal startup/list output unchanged
• add a /skills reload hint that points users to the verbose view when a slow skill load is detected

Architecture

High-level flow:

1. SkillManager.discoverSkills() walks builtin, user, alias, and trusted workspace skill roots in order of precedence.
2. Each root is loaded via loadSkillsFromDirWithReport(dir).
3. The loader times the directory scan, runs glob() for SKILL.md, and loads each discovered skill file.
4. Each load contributes a SkillLoadMetric, and each directory contributes a SkillDiscoveryReport.
5. The latest in-memory reports drive /skills list verbose and reload guidance.

Validation

Automated:

• npx vitest run src/skills/skillLoader.test.ts --coverage.enabled=false
• npx vitest run src/ui/commands/skillsCommand.test.ts src/commands/skills/list.test.ts --coverage.enabled=false
• npx tsc -p tsconfig.json --noEmit in packages/core
• npx tsc -p tsconfig.json --noEmit in packages/cli

Manual:

• verified /skills list verbose against local skills
• verified /skills reload guidance when a slow skill is detected
• validated the loader against a real remote SMB-backed skill root hosted on a GCP VM and accessed over Tailscale

Changed files

• packages/cli/src/commands/skills/list.test.ts (modified, +57/-2)
• packages/cli/src/commands/skills/list.ts (modified, +37/-10)
• packages/cli/src/config/extension-manager.ts (modified, +7/-3)
• packages/cli/src/ui/commands/skillsCommand.test.ts (modified, +66/-6)
• packages/cli/src/ui/commands/skillsCommand.ts (modified, +18/-9)
• packages/cli/src/ui/components/HistoryItemDisplay.tsx (modified, +1/-0)
• packages/cli/src/ui/components/views/SkillsList.tsx (modified, +20/-4)
• packages/cli/src/ui/types.ts (modified, +14/-1)
• packages/cli/src/utils/skillDiscovery.test.ts (added, +49/-0)
• packages/cli/src/utils/skillDiscovery.ts (added, +30/-0)
• packages/core/src/commands/memory.ts (modified, +2/-2)
• packages/core/src/config/config.ts (modified, +6/-0)
• packages/core/src/skills/skillLoader.test.ts (modified, +126/-1)
• packages/core/src/skills/skillLoader.ts (modified, +107/-13)
• packages/core/src/skills/skillManager.test.ts (modified, +63/-0)
• packages/core/src/skills/skillManager.ts (modified, +41/-6)