Skill Claude CodeCodex
Template for creating a new Agent Skill. Copy this folder, rename it to your skill's kebab-case name, and fill in every section. Use this as the starting point whenever you author a new skill for the AgentSkills library.
Skill Claude CodeCodex
Designs and analyzes A/B tests end-to-end — frames a sharp hypothesis, computes required sample size and test duration, runs significance tests (two-proportion z-test, Welch's t-test, chi-square), reports confidence intervals and lift, and flags common pitfalls like peeking, multiple comparisons, and Simpson's…
Skill Claude CodeCodex
Authors Architecture Decision Records (ADRs) that capture context, considered options with trade-offs, the chosen decision, and its consequences. Use this skill when the user wants to write, draft, document, or revise an architecture decision, an ADR, a design decision record, a technical decision log, or asks "why…
Skill Claude CodeCodex
Designs clean, consistent REST and GraphQL APIs covering resource modeling, URL structure, versioning, pagination, filtering, error formats (RFC 9457 Problem Details), idempotency, authentication, rate limiting, and machine-readable contracts (OpenAPI 3.1 / GraphQL SDL). Use this skill when designing a new API or…
Skill Claude CodeCodex
Writes precise, complete reference documentation for HTTP/REST APIs and authors valid OpenAPI 3.1 specifications, including endpoint pages, request/response schemas, parameter tables, authentication, pagination, code samples, and error tables. Use this skill when the user asks to "document an API", "write API…
Skill Claude CodeCodex
Systematically reduces AWS cloud spend by right-sizing over-provisioned compute, finding and eliminating idle or orphaned resources, committing to Savings Plans and Reserved Instances, and enforcing cost-allocation tagging. Use this skill when the user asks to "reduce AWS bill", "optimize cloud costs", "find idle…
Skill Claude CodeCodex
Writes robust, safe, shellcheck-clean Bash scripts using strict mode, defensive quoting, error traps, safe temp files, and signal handling. Use this skill when authoring or reviewing shell/Bash scripts, when asked to "harden a bash script", "add strict mode", "fix shellcheck warnings", "make this script safe", debug…
Skill Claude CodeCodex
Writes engaging technical blog posts with a strong hook, clear structure, concrete examples, and a memorable takeaway. Use this skill when the user asks to "write a blog post", "draft an article", "turn this into a blog post", "write up a tutorial", "explain X in a post", "create a dev.to / Medium / Hashnode article"…
Skill Claude CodeCodex
Distills a book into a clear, faithful summary at the depth the reader wants — from a one-paragraph gist to chapter-by-chapter notes — surfacing the core thesis, key ideas, memorable examples, and actionable takeaways without distortion. Use this skill when a user asks to "summarize this book", "give me the key…
Skill Claude CodeCodex
Maintains a CHANGELOG.md in the Keep a Changelog format with Semantic Versioning, grouping user-facing entries under Added/Changed/Deprecated/Removed/Fixed/Security and cutting dated releases from an Unreleased section. Use this skill when the user asks to "update the changelog", "add a changelog entry", "cut a…
Skill Claude CodeCodex
Selects the most appropriate chart type for a given dataset and analytical question, then produces a clean, honest, well-labeled visualization spec. Use this skill when a user asks "what chart should I use", "how should I visualize this data", "which graph fits", "make a chart for X", "is a pie chart right here", "how…
Skill Claude CodeCodex
Reviews a code diff or pull request for correctness bugs, security vulnerabilities, and quality/maintainability problems, producing severity-ranked findings with file/line references and concrete fix suggestions. Use this skill when the user asks to "review this PR", "review my diff", "code review", "look over these…
Skill Claude CodeCodex
Analyzes competitors and market position through structured data collection, feature/pricing comparison matrices, SWOT, positioning maps, and actionable strategic recommendations. Use this skill when the user asks to "analyze competitors", "do a competitive analysis", "compare us against X and Y", "build a competitor…
Skill Claude CodeCodex
Explains complex or technical concepts clearly at the right level for the audience, using layered depth, concrete analogies, worked examples, and checks for understanding — adapting from ELI5 to expert. Use this skill when the user asks to "explain X", "ELI5", "help me understand X", "what is X and how does it work"…
Skill Claude CodeCodex
Writes tailored, persuasive cover letters that connect a candidate's concrete achievements to a specific role and company — with a strong hook, evidence-backed body, and clear close. Use this skill when a user asks to "write a cover letter", "write a motivation letter", "cover letter for this job", "letter of…
Skill Claude CodeCodex
Builds, validates, explains, and previews cron expressions across Vixie/POSIX cron, systemd timers, and cloud schedulers, with explicit handling of timezones, DST, the day-of-month/day-of-week OR-logic trap, and overlap/missed-run pitfalls. Use this skill when the user asks to "write a cron job", "what does this cron…
Skill Claude CodeCodex
Designs robust ETL/ELT data pipelines covering ingestion, idempotency, schema evolution, orchestration, and data quality validation. Use this skill when the user asks to design, build, or review a data pipeline, ingest data from APIs/databases/files into a warehouse or lake, set up batch or streaming ETL/ELT, choose…
Skill Claude CodeCodex
Systematically root-causes software bugs using a reproduce → isolate → hypothesize → bisect → verify methodology, replacing guess-and-check debugging with a disciplined, evidence-driven investigation. Use this skill when a user reports a bug, a test is failing intermittently or consistently, behavior differs between…
Skill Claude CodeCodex
Builds a weighted decision matrix to compare options against criteria with transparent, reproducible scoring and sensitivity analysis. Use this skill when the user needs to choose between multiple options, compare alternatives, "help me decide", "which should I pick", weigh trade-offs, evaluate…
Skill Claude CodeCodex
Safely upgrades project dependencies by inventorying outdated packages, reading changelogs and migration guides, staging upgrades in isolated commits, running tests at each step, and rolling back cleanly on failure. Use this skill when asked to "upgrade dependencies", "bump packages", "update npm/pip/cargo/go…
Skill Claude CodeCodex
Authors small, secure, reproducible multi-stage Dockerfiles with build-cache optimization, pinned base images, non-root runtime users, and minimal attack surface. Use this skill when writing, reviewing, hardening, or shrinking a Dockerfile or container image — e.g. "write a Dockerfile", "containerize this app", "my…
Skill Claude CodeCodex
Drafts clear, professional emails with the right tone, structure, and a concrete call to action by clarifying audience, purpose, and desired outcome. Use this skill when the user asks to "write an email", "draft an email", "compose a message", "reply to this email", "make this email sound more…
Skill Claude CodeCodex
Designs robust, production-grade error handling — choosing between result types and exceptions, implementing retries with exponential backoff and jitter, applying timeouts and deadlines, adding circuit breakers, and building graceful degradation and fallbacks. Use this skill when writing or reviewing code that calls…
Skill Claude CodeCodex
Plans events end-to-end — birthdays, weddings, dinner parties, offsites, conferences, fundraisers — with a budget breakdown, guest and venue logistics, a backward-planned timeline, vendor checklist, run-of-show, and contingency plans. Use this skill when a user asks to "help me plan a party / wedding / event"…