Is the Ggsql skill free?

Yes. The skill itself is free from posit-dev/skills. SkillProof publishes the install command and an independent test verdict at no cost.

What is the Ggsql SkillProof Score?

8.8/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 8/10, docs & honesty 4/5.

How do I install Ggsql?

Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.

Can I use Ggsql with Cursor, Copilot, Gemini CLI, Codex or other AI tools?

The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.

Ggsql

Writes ggsql queries (grammar-of-graphics for SQL) using only documented clauses

by posit-dev · posit-dev/skills

Tested · Works

Install — copy the command Download source ↗

Test report

Verdict: Tested · Works
Score: 8.8/10
Tested: Jul 21, 2026
Environment: Claude Code 2.x (agent harness)
Upstream re-checked: Aug 10, 2026 · 90c41dc

Fetched SKILL.md at ggsql/ggsql/SKILL.md via raw GitHub; frontmatter parses with name+description, no bundled scripts to break, no hardcoded paths, no security smells. Trigger test (3 positive / 2 negative): 'write a ggsql query for a scatterplot of penguin bill length vs depth' YES, 'how do I make a stacked bar chart in ggsql' YES, 'turn this into a grammar-of-graphics SQL visualization query' YES; 'write a SQL query to sum revenue by month' NO (plain SQL, no viz), 'make a ggplot2 chart in R' NO (different tool) — all 5 correct. Output: same task (faceted density histogram of penguin body mass by species) written baseline vs skill. Baseline invented ggplot2-style syntax (GEOM histogram(x=..,y=..density..), FACET_WRAP(~species), bare `penguins`); skill produced documented ggsql (VISUALISE body_mass AS x, species AS fill FROM ggsql:penguins / DRAW histogram / REMAPPING density AS y / FACET species). Every baseline clause is absent from the ggsql grammar; every skill clause maps to a documented construct. Could not run the ggsql CLI (not installed) to confirm rendering, so output capped at 8.

Scored on four weighted criteria — install, triggering, output vs. baseline, docs. How scoring works

Installs cleanly 5/5
Triggers reliably 5/5
Output vs. baseline 8/10
Docs & honesty 4/5

What Ggsql does

A reference skill that teaches Claude the ggsql query grammar — a SQL extension for declarative data visualization (VISUALISE, DRAW, PLACE, SCALE, FACET, PROJECT, LABEL clauses, layer types, and named palettes). Triggers when the user wants to create, modify, understand, or validate a ggsql visualization query. Includes an optional CLI (ggsql exec/validate) for rendering and checking queries.

How to install Ggsql

git clone --depth 1 https://github.com/posit-dev/skills.git /tmp/ggsql-src
mkdir -p ~/.claude/skills
cp -R /tmp/ggsql-src/ggsql/ggsql ~/.claude/skills/ggsql
# Skill is a single self-contained SKILL.md (no bundled scripts).
# Optional runtime dep: the `ggsql` CLI must be on PATH to VALIDATE/RENDER queries
# (subcommands exec/run/validate/parse). Writing queries works without it.
# CLI source/docs: https://ggsql.org

Skills live in ~/.claude/skills/ (global) or .claude/skills/ (per-project). Restart Claude Code after installing.

Commands — how to trigger Ggsql

/ggsql Writes ggsql queries (grammar-of-graphics for SQL) using only documented clauses

It also activates on plain-language prompts like these:

Write a ggsql query to chart monthly sales
Explain what this ggsql visualization does
Modify this ggsql query to add a facet

Frequently asked questions

Is the Ggsql skill free?: Yes. The skill itself is free from posit-dev/skills. SkillProof publishes the install command and an independent test verdict at no cost.
Does Ggsql work with Claude Code?: We tested it with Claude Code 2.x (agent harness) on Jul 21, 2026. Verdict: Tested · Works. Fetched SKILL.md at ggsql/ggsql/SKILL.md via raw GitHub; frontmatter parses with name+description, no bundled scripts to break, no hardcoded paths, no security smells. Trigger test (3 positive / 2 negative): 'write a ggsql query for a scatterplot of penguin bill length vs depth' YES, 'how do I make a stacked bar chart in ggsql' YES, 'turn this into a grammar-of-graphics SQL visualization query' YES; 'write a SQL query to sum revenue by month' NO (plain SQL, no viz), 'make a ggplot2 chart in R' NO (different tool) — all 5 correct. Output: same task (faceted density histogram of penguin body mass by species) written baseline vs skill. Baseline invented ggplot2-style syntax (GEOM histogram(x=..,y=..density..), FACET_WRAP(~species), bare `penguins`); skill produced documented ggsql (VISUALISE body_mass AS x, species AS fill FROM ggsql:penguins / DRAW histogram / REMAPPING density AS y / FACET species). Every baseline clause is absent from the ggsql grammar; every skill clause maps to a documented construct. Could not run the ggsql CLI (not installed) to confirm rendering, so output capped at 8.
What is the Ggsql SkillProof Score?: 8.8/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 8/10, docs & honesty 4/5.
How do I install Ggsql?: Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.
Can I use Ggsql with Cursor, Copilot, Gemini CLI, Codex or other AI tools?: The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.