Checkpoint Validator

VerifiedCaution

Validate all checkpoints from an agent run directory in parallel. Spawns test-validator agents for each checkpoint and summarizes results.

Sby Skills Guide Bot
TestingIntermediate
7/30/2026
Claude Code
#test-validation#agent-runs#parallel-agents#checkpoint-analysis#claude-code

Recommended for

Automated summary

Validates all checkpoints in an agent run directory in parallel by spawning test-validator agents and summarizing their reports.

Strengths

  • Launches one validator per checkpoint in a single message, speeding up full-run coverage.
  • Includes an explicit verification step for sub-agent reports before presenting conclusions.
  • Handles several checkpoint directory layouts and can restrict validation to a specific problem.
  • Produces per-checkpoint reports with verdicts, summaries, and action items.

Limitations

  • Tightly coupled to Claude Code slash commands, the Task tool, and sub-agents.
  • Assumes checkpoint, specification, and test files already exist and does not describe the evaluation harness in detail.
  • Conclusions depend on sub-agent accuracy and still require manual review of TEST_BUG versus SOLUTION_BUG classifications.
When to use it

Use it when an agent has produced multiple checkpoints and each needs to be checked against its specification before fixing submissions.

When not to use it

Avoid it for ordinary unit testing or projects without a run directory, checkpoints, or configured test-validator agents.

Security analysis

Caution
Quality score80/100

The skill is a read-and-report orchestration workflow: it uses `find` for discovery, reads specs/tests, writes markdown reports, and delegates evaluation to sub-agents. There is no destructive command, no network exfiltration, no obfuscated payload, and no instruction to disable safety. The only notable risk is that it implicitly runs evaluation/test code located in a user-supplied directory and spawns agents against it, which is powerful-but-legitimate for a test-validation harness; this warrants caution rather than risky, ideally with sandboxing/path-confinement guidance.

Findings
  • •Instructs spawning multiple sub-agents that 'Run the evaluation' on arbitrary user-supplied run directories, which implies executing test/evaluation code found under {run_path} without any sandboxing, path-validation, or trust guidance.
  • •Spawns parallel Task agents and writes report files into problems/{problem}/... without guidance on validating that run_path/problem_name are within an expected workspace, so paths from user input are used directly.
  • •Uses a bash `find` command with the user-supplied `{run_path}` interpolated unquoted, so a path containing spaces or shell metacharacters could break parsing or inject commands if pasted verbatim; quoting the placeholder would remove this low-severity risk.
  • •Spawns sub-agents that read spec/test files and write report files (`problems/{problem}/checkpoint_N_report.md`); writes are confined to that relative output directory, which is a normal, non-destructive side effect.
  • •No network calls, credential access, destructive deletions, obfuscated payloads, or safety-disabling instructions present.
How this analysis is made

Examples

Validate a full run
/validate-run /runs/agent-2025-06-01
Validate one problem
/validate-run /runs/agent-2025-06-01 file_backup
Validate local checkpoints
/validate-run ./output/run_42

name: validate-run description: Validate all checkpoints from an agent run directory in parallel. Spawns test-validator agents for each checkpoint and summarizes results. Invoke with /validate-run <run_path> [problem].

Validate Run

Analyze all checkpoints from an agent's run directory, spawning test-validator agents in parallel to validate each checkpoint against its specification.

Usage:

  • /validate-run /path/to/run/directory - Validate all problems/checkpoints
  • /validate-run /path/to/run/directory file_backup - Validate specific problem only

IMPORTANT: You Must Verify Sub-Agent Results

Sub-agents (Sonnet) make mistakes. After collecting their reports, you MUST:

  1. Read the actual spec and test files yourself
  2. Verify each TEST_BUG classification is correct
  3. Check that proposed fixes are actually valid
  4. Correct any errors before presenting to the user

See Step 4 for detailed verification process.


Step 1: Discover Checkpoints

The run directory structure varies. Look for checkpoints in these patterns:

# Agent run output structure
{run_path}/submissions/{problem}/checkpoint_N/

# Or direct problem solutions
{run_path}/checkpoint_N/

# Or solutions directory
{run_path}/solutions/checkpoint_N/

Use this command to discover checkpoints:

find {run_path} -type d -name "checkpoint_*" | sort

For each checkpoint found, extract:

  • problem_name: The problem being tested (from path or user input)
  • checkpoint: The checkpoint number (e.g., checkpoint_1, checkpoint_2)
  • snapshot_path: Full path to the checkpoint directory

Step 2: Launch Validators in Parallel

CRITICAL: Launch ALL test-validator agents in a SINGLE message with multiple Task tool calls.

For each checkpoint discovered, spawn a test-validator agent:

Task tool call 1: test-validator for {problem} checkpoint_1
Task tool call 2: test-validator for {problem} checkpoint_2
Task tool call 3: test-validator for {problem} checkpoint_3
...

Prompt template for each agent:

Validate the following checkpoint:

Problem: {problem_name}
Checkpoint: checkpoint_{N}
Snapshot Path: {snapshot_path}

Run the evaluation, analyze all test results against the specification, and save your report to:
problems/{problem_name}/checkpoint_{N}_report.md

Focus on determining whether any test failures indicate:
1. Solution bugs (code doesn't match spec)
2. Test bugs (tests expect behavior not in spec)
3. Spec ambiguity (unclear requirements)

Step 3: Collect Results

After all validators complete, read each report:

problems/{problem}/checkpoint_1_report.md
problems/{problem}/checkpoint_2_report.md
...

Extract from each report:

  • VERDICT line (the overall conclusion)
  • SUMMARY table (counts)
  • ACTION ITEMS (what needs fixing)

Step 4: VERIFY SUB-AGENT RESULTS (CRITICAL)

WARNING: Sub-agents (Sonnet) can and do make mistakes. You MUST verify their findings.

DO NOT blindly trust sub-agent reports. For each finding:

  1. Read the spec quote - Does it actually support the sub-agent's conclusion?
  2. Read the test assertion - Is the sub-agent's interpretation correct?
  3. Check the classification - Does TEST_BUG vs SOLUTION_BUG make sense?
  4. Verify the proposed fix - Is it actually more lenient, or just different?

Common Sub-Agent Mistakes to Catch:

| Mistake | How to Spot It | |---------|----------------| | Wrong classification | Spec clearly requires X, but agent says TEST_BUG | | Invented spec requirements | Agent quotes spec but adds interpretation not present | | Missed spec text | Agent says "spec silent" but spec does address it | | Bad fix proposal | "Fix" changes behavior instead of relaxing constraint | | Inconsistent verdicts | SUMMARY counts don't match FINDINGS |

Verification Process:

For each report with TESTS_HAVE_BUGS or MIXED verdict:

1. Open the spec file: problems/{problem}/checkpoint_N.md
2. Open the test file: problems/{problem}/tests/test_checkpoint_N.py
3. For each TEST_BUG finding:
   a. Find the spec quote - is it accurate and complete?
   b. Find the test assertion - does it really expect what agent claims?
   c. Is the classification correct?
   d. Is the proposed fix actually valid?
4. Correct any errors before including in final summary

If You Find Sub-Agent Errors:

  • Override the classification in your summary
  • Note the correction so user knows agent was wrong
  • Provide correct fix if agent's fix was wrong
  • Adjust counts in the summary table

Example correction note:

### Corrections to Sub-Agent Reports

- checkpoint_2 FINDING-003: Reclassified from TEST_BUG → SOLUTION_BUG
  (Agent missed spec requirement on line 45: "MUST return exactly 1")

Step 5: Generate Summary Report

Present a consolidated summary to the user:

# Run Validation Summary

**Run Path**: {run_path}
**Date**: {date}

## Overall Results

| Problem | Checkpoint | Verdict | Failing | Solution Bugs | Test Bugs |
|---------|------------|---------|---------|---------------|-----------|
| file_backup | 1 | SOLUTION_CORRECT | 0 | 0 | 0 |
| file_backup | 2 | TESTS_HAVE_BUGS | 3 | 0 | 3 |
| file_backup | 3 | MIXED | 5 | 2 | 3 |

## Verdicts by Type

- SOLUTION_CORRECT: N checkpoints
- SOLUTION_HAS_BUGS: N checkpoints
- TESTS_HAVE_BUGS: N checkpoints
- MIXED: N checkpoints
- SPEC_AMBIGUOUS: N checkpoints

## Action Items Required

<!-- Fix preference: MAKE_LENIENT > REMOVE_TEST >> UPDATE_SPEC -->

### Test Fixes: MAKE_LENIENT (Preferred)
- [ ] file_backup checkpoint_2 `test_error_code`: Change `assert rc == 1` → `assert rc != 0`
- [ ] file_backup checkpoint_3 `test_output_order`: Change `assert x == [a,b]` → `assert set(x) == {a,b}`

### Test Fixes: REMOVE_TEST
- [ ] file_backup checkpoint_2 `test_undefined_edge`: DELETE (tests undefined behavior)

### Solution Fixes
- [ ] file_backup checkpoint_3: {specific fix from report}

### Spec Clarifications (LAST RESORT)
- [ ] {only if test cannot be made lenient or removed}

## Corrections to Sub-Agent Reports

<!-- Include this section if you found any errors in sub-agent analysis -->

- checkpoint_2 FINDING-003: Reclassified TEST_BUG → SOLUTION_BUG
  - Agent claimed: "spec is silent on error codes"
  - Actually: spec line 45 says "MUST return exit code 1"
  - Correct fix: Solution must return 1, not test change needed

## Detailed Reports

Reports saved to:
- problems/file_backup/checkpoint_1_report.md
- problems/file_backup/checkpoint_2_report.md
- problems/file_backup/checkpoint_3_report.md

Quick Verdicts Reference

| Verdict | Meaning | Action | |---------|---------|--------| | SOLUTION_CORRECT | All good, solution passes | None | | SOLUTION_HAS_BUGS | Solution needs fixes | Fix solution code | | TESTS_HAVE_BUGS | Tests are wrong | Fix test assertions | | MIXED | Both have issues | Fix both | | SPEC_AMBIGUOUS | Spec unclear | Clarify spec first |

Fix Preference Hierarchy

When tests have bugs, prefer fixes in this order:

1. MAKE_LENIENT  ← STRONGLY PREFERRED (relax assertion)
2. REMOVE_TEST   ← If test is fundamentally flawed
3. UPDATE_SPEC   ← LAST RESORT ONLY
  • Making tests lenient keeps coverage while accepting valid implementations
  • Removing tests is better than keeping broken ones
  • Changing specs is dangerous and affects all documentation

Recommended Tools for Lenient Tests

Many strict tests can be fixed using these tools:

| Tool | Use Case | Example | |------|----------|---------| | deepdiff | Ignore order, precision, extra fields | DeepDiff(a, b, ignore_order=True) | | jsonschema | Validate structure not exact values | validate(output, schema) | | normalize() | Handle whitespace, case, key order | normalize(actual) == normalize(expected) |

# Common fix pattern:
from deepdiff import DeepDiff

# BEFORE (too strict):
assert actual == expected

# AFTER (lenient):
diff = DeepDiff(expected, actual, ignore_order=True, significant_digits=5)
assert not diff

Example

User: /validate-run problems/file_backup/solutions file_backup

Assistant: [discovers checkpoints, launches test-validator agents in parallel]

Assistant: All validators complete. Here is the summary:

# Run Validation Summary
...

From the file to a first result

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View the source and supporting files

This download contains SKILL.md only. Any scripts, references, templates and dependencies are not included. Get the required files from the source, preserving their directory structure, before continuing.

1. Download the file

Download SKILL.md

From the root of a test project, save the file as .skill-downloads/checkpoint-validator-ms71b305/SKILL.md, or use the command below. This folder is for inspecting the skill before installation.

Command for macOS/Linux or WSL: requires a POSIX shell and curl. On Windows without WSL, use the download button and create the folder manually.

mkdir -p '.skill-downloads/checkpoint-validator-ms71b305' && curl --fail --show-error --location 'https://skills-guides.com/api/skills/checkpoint-validator-ms71b305/download' --output '.skill-downloads/checkpoint-validator-ms71b305/SKILL.md.part' && mv '.skill-downloads/checkpoint-validator-ms71b305/SKILL.md.part' '.skill-downloads/checkpoint-validator-ms71b305/SKILL.md'

2. Check prerequisites

Read SKILL.md before using it. If it references scripts or external services, inspect them and prepare the required access in your test environment.

No recognized prerequisites section in this file. This does not mean it is self-contained: libraries, tools and access requirements may be mentioned elsewhere in the content or source repository.

The platforms on this page are catalog indications. The paths below follow tool documentation; they do not prove this skill has been run in those tools. No minimum tool version is confirmed for this listing.

3. Load the skill

After inspection, copy the complete folder into your project using one of the commands below, then open a new tool session. The command stops if a folder with the same name already exists: compare the files before replacing it.

Claude Code
test -f '.skill-downloads/checkpoint-validator-ms71b305/SKILL.md' && test -s '.skill-downloads/checkpoint-validator-ms71b305/SKILL.md' && mkdir -p '.claude/skills' && test ! -e '.claude/skills/validate-run' && cp -R '.skill-downloads/checkpoint-validator-ms71b305' '.claude/skills/validate-run'

OpenSkills

OpenSkills must already be installed. The local install/read procedure is checked with OpenSkills 1.5.0, which requires Node.js ≥ 20.6.0. Catalog slugs are not resolved automatically.

Official OpenSkills installation
openskills install './.skill-downloads/checkpoint-validator-ms71b305'

openskills read 'checkpoint-validator-ms71b305'

Reading should display the installed file content and its base directory. It does not run the skill or install its dependencies.

For an agent that reads AGENTS.md, then sync the index. This command changes AGENTS.md: review the diff before using it.

openskills sync

Manual method or another tool: attach SKILL.md to a conversation, or open it in an agent that can read files. Include any required supporting resources. No universal folder is recognized by every tool.

4. Try a first task

Use a short, synthetic input: an API endpoint, a small document or an interface brief. In a new conversation, attach the file or give the agent its path, then adapt this request:

Read .skill-downloads/checkpoint-validator-ms71b305/SKILL.md and apply its instructions to this example: [describe a test input]. Identify any missing files, dependencies or access. Produce the result requested by the skill without inventing data or running unreviewed scripts.

Expected result: output matching the skill instructions, or a precise list of missing prerequisites. A read confirmation alone does not validate a first use. If an external resource is unavailable, that path remains untested.

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