skill-creator

Create, evaluate, and iteratively improve Claude skills with benchmark-driven testing workflows.

2|Updated May 30, 2026
One-click install
npx skills add https://github.com/virahitvin8/crafty-gis --skill skill-creator-virahitvin8
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: skill-creator
Source: https://github.com/virahitvin8/crafty-gis/tree/main/GIT_STAR/assignment-generator/antigravity-skills-main/antigravity-skills-main/skills/skill-creator
Command: npx skills add https://github.com/virahitvin8/crafty-gis --skill skill-creator-virahitvin8

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes scripts (resource) and references (resource) and assets (resource) components.

What problem does it solve? Writing an effective skill is hard to get right on the first try — descriptions may fail to trigger, instructions may be ambiguous, and there is no built-in way to measure whether a skill actually improves results. This Skill provides a structured create-test-review-iterate loop with quantitative benchmarking so skills are validated against real test prompts rather than guesswork. ## Core Features & Use Cases - Guided Skill Authoring: Interviews the user about intent, trigger contexts, and output formats, then drafts a SKILL.md following progressive disclosure and writing-style best practices. - Parallel Evaluation Runs: Spawns with-skill and baseline subagent runs for each test prompt, captures timing and token data, and grades outputs against assertions. - Benchmark Aggregation & Review UI: Aggregates pass rates, time, and token statistics into benchmark.json/benchmark.md and launches an HTML viewer for qualitative feedback. - Description Optimization: Generates trigger/no-trigger eval queries and runs an automated loop that rewrites the skill description to maximize triggering accuracy on held-out test queries. - Use Case: A user wants a skill that formats weekly sales reports. This Skill drafts it, runs three realistic test prompts with and without the skill, shows a side-by-side benchmark, collects feedback, and iterates until the outputs pass all assertions. ## Quick Start Ask the assistant to create a new skill for your workflow and let it draft, test, and benchmark the skill iteratively.

Frequently Asked Questions about skill-creator

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I create a new Claude skill from scratch?

Define what the skill should do, when it should trigger, and its output format, then write a SKILL.md with name and description frontmatter plus markdown instructions. This Skill guides the interview, drafts the file, and validates it with test prompts.

How do I test whether my skill actually improves results?

Run each test prompt twice in parallel — once with the skill and once without — then grade outputs against assertions. The aggregate_benchmark.py script computes pass rates, time, and token deltas between configurations.

How can I improve a skill description so it triggers correctly?

Generate 20 realistic should-trigger and should-not-trigger queries, then run the run_loop.py optimization script. It rewrites the description iteratively and selects the best version by held-out test score to avoid overfitting.

What is the difference between with_skill and baseline benchmark runs?

With-skill runs execute the test prompt with the skill loaded, while baseline runs use no skill (for new skills) or the previous version (for improvements). Comparing them isolates the skill's actual contribution to output quality.

Does skill evaluation work on Claude.ai without subagents?

Yes, but with limitations. Without subagents you run test prompts sequentially yourself, skip baseline comparisons and quantitative benchmarking, and collect qualitative feedback inline instead of using the browser-based review viewer.

When should a skill bundle scripts instead of inline instructions?

Bundle a script when test runs show subagents repeatedly writing the same helper code, or when a task is deterministic and repetitive. Scripts in the scripts/ directory execute without loading into context, saving tokens on every invocation.