How do I install the Holdout Validation Claude Code skill?

Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/holdout-validation/SKILL.md and restart Claude Code. Both flows are detailed at https://claudskills.com/install/.

Is this skill free to install?

Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.

ClaudSkills / General / general-misc

Holdout Validation

Category: General · Sub-category: general-misc · Last updated: 2026-05-08

type:review

Cross-reference agent self-review claims against actual file state using hidden holdout scenarios, producing mapped P1/P2/P3 findings that reference visible acceptance criteria only. Use when verifying implementation completeness after self-review in start (Phase 4 VERIFY), address (convergence check), or review (parallel fan-out). Also use when an agent claims evidence for a criterion but the file state may not support the claim. This skill MUST be consulted because it detects blind spots in self-review that no other skill catches; a conversational answer cannot systematically test holdout scenarios or cross-reference claims against files.

From the source SKILL.md

You are an independent claim verifier — you cross-reference agent self-review claims against actual file state using hidden holdout scenarios that the executing agent never sees. Your core insight: agents often claim "test added for X" or "error handling covers Y" without the claim being true. You verify the claim against the files.

What this skill does

Holdout Validation is a community-contributed Claude Code skill in the general-misc sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/holdout-validation/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use when verifying implementation completeness after self-review in start (Phase 4 VERIFY), address (convergence check), or review (parallel fan-out). Also use when an agent claims evidence for a criterion but the file state may not support the claim.

Who uses this skill

The Holdout Validation skill is built for Claude Code users and developers across all disciplines looking for general-purpose AI assistance. It is part of the open ClaudSkills registry, a community-curated catalog of 56,000+ capabilities you can install for Claude Code — the Claude CLI agent.

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/holdout-validation
curl -L https://claudskills.com/skills/holdout-validation/SKILL.md \
  -o ~/.claude/skills/holdout-validation/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/holdout-validation/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/holdout-validation/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\holdout-validation\SKILL.md on Windows. See the full install guide for step-by-step instructions.

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

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