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by Alberto Leal

Programmatic hunk selection for the jj (Jujutsu) VCS. Select individual diff hunks with a query language instead of an interactive TUI, then split, commit, squash, diffedit, restore, or absorb them. Use when splitting a jj commit, committing or squashing part of the working copy, undoing single hunks, selecting changes by file/content/function/class, or when `jj split -i` would need an editor an agent cannot drive.

by Alberto Leal

jq — the command-line JSON processor and its filter language for filtering, transforming, and reshaping JSON. Use when extracting fields/nested paths on the CLI, `select`-ing arrays of objects, building new JSON, emitting CSV/TSV with `@csv`/`@tsv`, getting raw strings with `jq -r`, slurping (`-s`) and aggregating (`add`, `group_by`), NDJSON pipelines (`-c`), or injecting shell values with `--arg`/`--argjson`. Includes `(jq 1.X+)` annotations; the jq CLI/filter language, not bindings (jaq/gojq).

by Alberto Leal

The k3s lightweight CNCF-certified Kubernetes distribution as a single binary (bundles containerd, flannel, CoreDNS, Traefik, ServiceLB, local-path-provisioner, metrics-server). Use when installing/running a lightweight cluster, bootstrapping single-node or HA control planes, joining agent nodes, embedded etcd vs external datastore, managing tokens, rotating certs, etcd snapshots, secrets encryption, airgap installs, disabling components, or upgrading k3s. Includes `(k3s vX.Y+)` annotations.

by Alberto Leal

Author and operate Kubernetes workloads with kubectl and YAML manifests — the kubectl CLI plus core resource authoring (Deployments, StatefulSets, Jobs/CronJobs, Services, Ingress, ConfigMaps/Secrets, PV/PVC, RBAC). Use when writing/debugging manifests, running kubectl (apply/diff/rollout/logs/exec/debug), fixing CrashLoopBackOff/Pending pods, managing contexts, or checking RBAC with auth can-i. Includes `(k8s 1.X+)` annotations. For installing/running a lightweight cluster see the k3s skill.

by Will Smith

Managing Linear issues, projects, and teams. Use when working with Linear tasks, creating issues, updating status, querying projects, or managing team workflows.

by Alberto Leal

Write mathematics in a long-form, understanding-focused style with detailed proofs and rich exposition. Use when explaining mathematical concepts, writing proofs, tutoring math, creating educational math content, or when the user asks for mathematical explanations. Inspired by Jay Cummings' Real Analysis and Chartrand's Mathematical Proofs.

by Alberto Leal

Generate, validate, and fix diagrams from Mermaid markup using mmdc. Use when creating flowcharts, sequence diagrams, class diagrams, converting .mmd files to images/SVG/PDF, or validating and fixing Mermaid diagram syntax.

by Alberto Leal

Install and maintain a "model routing" section in a project's CLAUDE.md that teaches Claude Code which model to use for which work, including delegating to GPT models via the Codex CLI. Use when adding model-picking guidance to CLAUDE.md, setting up Codex/GPT as a delegation target or fallback, or routing subagent and workflow tasks across models by cost, intelligence, and taste.

by Steph Ango

Create and edit Obsidian Bases (.base files) with views, filters, formulas, and summaries. Use when working with .base files, creating database-like views of notes, or when the user mentions Bases, table views, card views, filters, or formulas in Obsidian.

by Steph Ango

Create and edit Obsidian Flavored Markdown with wikilinks, embeds, callouts, properties, and other Obsidian-specific syntax. Use when working with .md files in Obsidian, or when the user mentions wikilinks, callouts, frontmatter, tags, embeds, or Obsidian notes.

by Alberto Leal

oxfmt — the fast Rust formatter from the oxc project, a Prettier-compatible alternative formatting JS/TS/JSX plus JSON, CSS, YAML, TOML, GraphQL, Markdown and Vue. Use when formatting or checking with oxfmt, configuring `.oxfmtrc.json`, migrating off Prettier/Biome (`--migrate`), or enabling built-in `sortImports`/`sortPackageJson`/`sortTailwindcss`. Note: bare `oxfmt` REWRITES FILES IN PLACE. The formatter — not oxlint, Prettier/Biome, or ruff format.

by Alberto Leal

oxlint — the extremely fast (Rust) JavaScript/TypeScript linter from the oxc project, an ESLint alternative that needs no config to start. Use when linting JS/TS/JSX/Vue, writing `.oxlintrc.json`, selecting rules via `plugins` + `categories` (correctness, suspicious, pedantic, perf, style, restriction, nursery), running `--fix`/`--fix-suggestions`/`--fix-dangerously`, suppressing with `// oxlint-disable`, or migrating from ESLint. The linter — not oxfmt, ESLint/Biome, or ruff.

by Alberto Leal

Browser automation with Playwright for Python. Use when testing websites, taking screenshots, filling forms, scraping web content, or automating browser interactions. Triggers on browser, web testing, screenshots, selenium, puppeteer, or playwright.

by Alberto Leal

PostgreSQL server administration & operations. Use when configuring a server (`postgresql.conf`, `ALTER SYSTEM`, GUCs), managing roles/privileges (`GRANT`/`REVOKE`), authentication (`pg_hba.conf`, scram-sha-256), backup/restore (`pg_dump`, `pg_basebackup`, incremental, PITR), replication (streaming, logical, slots, failover), `pg_upgrade`, or monitoring (`pg_stat_activity`/`pg_stat_io`). Includes `(pgNN+)` annotations. Server ops — client psql, SQL postgres-sql, tuning postgres-performance.

by Alberto Leal

PostgreSQL extension management and the bundled `contrib` catalog. Use when running `CREATE/ALTER/DROP EXTENSION`, listing extensions (`\dx`), or choosing which contrib module enables a feature — FDWs (`postgres_fdw`, `dblink`), trigram search (`pg_trgm`), crypto/UUIDs (`pgcrypto`), types (`hstore`/`ltree`/`citext`), query stats (`pg_stat_statements`, `auto_explain`), forensics (`pageinspect`, `amcheck`). Covers trusted extensions & `shared_preload_libraries`. Includes `(pgNN+)` annotations.

by Alberto Leal

PostgreSQL query & performance tuning. Use when a query is slow, reading an `EXPLAIN [ANALYZE]` plan (scan/join nodes, estimate skew), choosing an index type/columns (btree/GIN/GiST/SP-GiST/BRIN/hash; partial/expression/covering), fixing planner estimates with statistics, diagnosing MVCC bloat/VACUUM/autovacuum lag, or tuning planner GUCs (`random_page_cost`, `work_mem`). Includes `(pgNN+)` annotations. Tuning only — client -> psql, SQL -> postgres-sql, config -> postgres-admin.

by Alberto Leal

The PostgreSQL SQL dialect & data types that set Postgres apart from generic SQL. Use when writing or debugging Postgres-specific SQL — upsert (`ON CONFLICT`), `RETURNING`, `MERGE`, CTEs, window frames, `GROUPING SETS`, `LATERAL`, generated/identity columns, partitioning, `jsonb`/jsonpath/SQL-JSON (`JSON_TABLE`), arrays, ranges, composite/enum/domain types, `uuidv7()`. Includes `(pgNN+)` annotations. Dialect & types — client -> psql, tuning -> postgres-performance, config -> postgres-admin.

by Alberto Leal

psql — PostgreSQL's interactive terminal client and SQL script runner. Use when connecting to or inspecting a Postgres DB from a terminal, running SQL scripts or one-off queries in shells/CI/agents (`-c`/`-f`/`-qAtX`/`--csv`), using meta-commands (the `\d` family, `\copy`, `\watch`, `\gexec`, `\if` scripting, `\pset`/`\x`, variables), `.psqlrc`, or fixing connection/auth issues. Includes `(pgNN+)` annotations. The psql client only — SQL syntax -> postgres-sql, server admin -> postgres-admin.

by Datadog

Datadog CLI (pup) for observability, monitoring, logs, APM, security, and infrastructure. Use when querying Datadog metrics, searching logs, managing monitors, investigating incidents, or performing Datadog API operations.

by Alberto Leal

pytest — Python testing framework and idioms beyond unittest. Use when writing, running, or configuring pytest tests — plain `assert` (rewritten), DI `@pytest.fixture` (scopes/autouse/yield/conftest), `@pytest.mark.parametrize`, `skip`/`skipif`/`xfail` + markers, `raises`/`warns`/`approx`, fixtures (`tmp_path`/`monkeypatch`/`capsys`/`caplog`), the CLI (`-k`/`-m`/`-x`/`--lf`/`--pdb`), config (`pyproject.toml`/`pytest.ini`). Includes `(pytest N.M+)` annotations. Not unittest, tox, or coverage.

by Alberto Leal

Measure Python complexity per function and per call path with ruff and complexipy; optionally add Jev judgments through configurable providers (Vercel by default). Use when prioritizing refactors, investigating over-layering, or verifying that a refactor improved the whole path. Without the selected provider key, semantic review is skipped and static analysis continues. Tests verify behavior.

by Vercel Engineering

React and Next.js performance optimization guidelines from Vercel Engineering. Use when writing, reviewing, or refactoring React/Next.js code for optimal performance. 62 rules across 8 categories covering waterfalls, bundle size, server-side, re-renders, and rendering.

by Alberto Leal

Fast, gitignore-aware recursive content search with the `ripgrep` (`rg`) command-line tool — a smarter, faster `grep`. Use when searching code or text for a regex across a directory tree, filtering by file type or glob, listing/counting matches, doing search-and-replace previews, or gitignore-aware code search. Triggers on mentions of ripgrep or rg. The rg CLI tool, distinct from the file-search/fuzzy-search MCP servers.

by Alberto Leal

ruff — Astral's one fast (Rust) binary that is both a Python linter (`ruff check`) and a Black-compatible formatter (`ruff format`). Use when linting or formatting Python, configuring `[tool.ruff]`/`ruff.toml`, choosing rules with `select`/`extend-select`/`ignore`, looking up codes like F401/E501/B008, applying fixes (`--fix`, `--unsafe-fixes`), suppressing (`# noqa`, `# ruff: ignore[...]`), or enabling preview rules. Includes `(ruff 0.X+)` + preview annotations. Not uv or ty.