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hatch-pet

Create, repair, validate, preview, and package Codex-compatible animated pet spritesheets from character art, screenshots, generated images, or visual references. Use when a user wants to hatch a Codex pet, create a custom animated pet, or build a built-in pet asset with an 8x9 atlas, transparent unused cells, row-by-row animation prompts, QA contact sheets, preview videos, and pet.json packaging. This skill composes the installed $imagegen system skill for visual generation and uses bundled scripts for deterministic spritesheet assembly.

Quality

86%

Does it follow best practices?

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SecuritybySnyk

Passed

No findings from the security scan

The canonical home for this skill is hatch-pet in nexu-io/open-design

SKILL.md
Quality
Evals
Security

Quality

Content

77%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

The body delivers exceptionally actionable, well-sequenced guidance with strong validation and repair loops for a complex multi-stage pipeline. Its weaknesses are redundancy (the Rules, Subagent, and Acceptance Criteria sections repeat earlier content, including duplicating qa-rubric.md) and underused bundle references — two of three reference files are never linked and the referenced scripts are not present in the bundle.

Suggestions

Replace the duplicated Acceptance Criteria content with a pointer to references/qa-rubric.md (and link references/codex-pet-contract.md for the atlas/package contract), keeping only the acceptance criteria that are not already in those files.

Consolidate the running-left mirror policy, subagent boundaries, and transparency rules so each is stated once; have the Rules section and subagent template reference the canonical section instead of restating it.

Trim the eight-entry pet-naming example list to 3-4 representative examples, and either include the referenced scripts/ in the bundle or note explicitly that they live under ${CODEX_HOME:-$HOME/.codex}/skills/hatch-pet rather than in the skill bundle.

DimensionReasoningScore

Conciseness

Most content is skill-specific policy Claude could not infer (transparency rules, mirror criteria, subagent boundaries), but it could be tightened: the Rules section restates the Generation Delegation and Subagent rules (the running-left mirror policy appears three times), the subagent template re-lists the transparency rules again, and Acceptance Criteria duplicates references/qa-rubric.md. This is the 'mostly efficient but could be tightened' anchor rather than 4, since the duplication exceeds minor over-explanation.

3 / 5

Actionability

Every workflow step is copy-paste executable: exact bash invocations with flags for all seven scripts (prepare_pet_run.py, pet_job_status.py, record_imagegen_result.py, finalize_pet_run.py, queue_pet_repairs.py, derive_running_left_from_running_right.py, generate_pet_images.py), expected output directory trees, and a complete subagent handoff template. Fully executable guidance covering the common cases, matching the 5 anchor.

5 / 5

Workflow Clarity

The Default Workflow is a clear numbered sequence (prepare → generate/record → finalize) with explicit validation checkpoints (review qa/contact-sheet.png, qa/review.json, final/validation.json before acceptance) and a repair feedback loop (queue_pet_repairs.py → regenerate only the failed row → re-validate), plus identity-drift blockers. This matches the 5 anchor's explicit validation with error-recovery loops.

5 / 5

Progressive Disclosure

Only one of the three bundle reference files is clearly signaled ("Atlas follows the row/frame counts in references/animation-rows.md"); codex-pet-contract.md and qa-rubric.md exist in the bundle but are never linked from the body, and their content is instead duplicated inline in Acceptance Criteria. Additionally, the seven scripts referenced via $SKILL_DIR/scripts/ are absent from the provided bundle. This matches the 3 anchor (references present but not clearly signaled, content that should be separate is inline) rather than 4.

3 / 5

Total

16

/

20

Passed

Description

92%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A strong description: third-person, action-dense, with an explicit 'Use when' clause containing concrete trigger phrases that match the skill's trigger list. The only weakness is slightly incomplete synonym coverage for natural user phrasings like 'digital pet' or 'pixel pet'.

DimensionReasoningScore

Specificity

"Create, repair, validate, preview, and package" lists five concrete lifecycle actions, reinforced with specific artifacts ("8x9 atlas", "transparent unused cells", "QA contact sheets", "preview videos", "pet.json packaging"). This matches the comprehensive-coverage anchor; it is not 4 because the action list spans the full create-to-package lifecycle with no gaps.

5 / 5

Completeness

It explicitly answers both questions: the "what" is the multi-action creation/repair/validation/packaging pipeline, and the "when" is a concrete "Use when a user wants to hatch a Codex pet, create a custom animated pet, or build a built-in pet asset..." clause. This matches the 5 anchor's requirement of both what and when with concrete trigger phrases.

5 / 5

Trigger Term Quality

Natural phrases like "hatch a Codex pet", "create a custom animated pet", and "build a built-in pet asset" align well with what a user would say. It falls short of 5 because common synonyms such as "pixel pet", "digital pet", or "virtual pet" are missing, though it is clearly above the 3 anchor's partial coverage.

4 / 5

Distinctiveness Conflict Risk

"Codex-compatible animated pet spritesheets" carves out a clear niche with distinct triggers ("hatch a Codex pet", "spritesheet pet") that are unlikely to fire for unrelated skills. Minimal conflict risk, matching the 5 anchor.

5 / 5

Total

19

/

20

Passed

Validation

87%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 14 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

frontmatter_unknown_keys

Unknown frontmatter key(s) found; consider removing or moving to metadata

Warning

referenced_paths_exist

Referenced path issues: 5 missing

Warning

Total

14

/

16

Passed

Repository

nexu-io/open-design

Path

plugins/_official/examples/hatch-pet/SKILL.md

Reviewed

Table of Contents

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