# Cli

> >

- **Type:** Skill
- **Install:** `agentstack add skill-posit-dev-skills-cli`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [posit-dev](https://agentstack.voostack.com/s/posit-dev)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [posit-dev](https://github.com/posit-dev)
- **Source:** https://github.com/posit-dev/skills/tree/main/r-lib/cli

## Install

```sh
agentstack add skill-posit-dev-skills-cli
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# CLI for R Packages

## When to Use What

task: Display error with context and formatting
use: `cli_abort()` with inline markup and bullet lists

task: Show warning with formatting
use: `cli_warn()` with inline markup

task: Display informative message
use: `cli_inform()` with inline markup

task: Show progress for counted operations
use: `cli_progress_bar()` with total count

task: Show simple progress steps
use: `cli_progress_step()` with status messages

task: Format code or function names
use: `{.code ...}` or `{.fn package::function}`

task: Format file paths
use: `{.file path/to/file}`

task: Format package names
use: `{.pkg packagename}`

task: Format variable names
use: `{.var variable_name}`

task: Format values
use: `{.val value}`

task: Handle singular/plural text
use: `{?s}` or `{?y/ies}` with pluralization

task: Create headers
use: `cli_h1()`, `cli_h2()`, `cli_h3()`

task: Create alerts
use: `cli_alert_success()`, `cli_alert_danger()`, `cli_alert_warning()`, `cli_alert_info()`

task: Create lists
use: `cli_ul()`, `cli_ol()`, `cli_dl()` with `cli_li()`

## Inline Markup Essentials

Use inline markup with `{.class content}` syntax to format text:

```r
# Basic formatting
cli_text("Function {.fn mean} calculates averages")
cli_text("Install package {.pkg dplyr}")
cli_text("See file {.file ~/.Rprofile}")
cli_text("{.var x} must be numeric, not {.obj_type_of {x}}")
cli_text("Got value {.val {x}}")

# Code formatting
cli_text("Use {.code sum(x, na.rm = TRUE)}")

# Paths and arguments
cli_text("Reading from {.path /data/file.csv}")
cli_text("Set {.arg na.rm} to TRUE")

# Types and classes
cli_text("Object is {.cls data.frame}")

# Emphasis
cli_text("This is {.emph important}")
cli_text("This is {.strong critical}")

# Fields
cli_text("The {.field name} field is required")
```

### Vector Collapsing

Vectors are automatically collapsed with commas and "and":

```r
pkgs  Installing packages: dplyr, tidyr, and ggplot2

files  Found 2 files: data.csv and script.R
```

### Escaping Braces

Use double braces `{{` and `}}` to escape literal braces:

```r
cli_text("Use {{variable}} syntax in glue")
#> Use {variable} syntax in glue
```

**For complete markup reference**: See [references/inline-markup.md](references/inline-markup.md) for all 50+ inline classes, edge cases, nesting rules, and advanced patterns.

## Pluralization Basics

Use `{?}` for pluralization with three patterns:

### Single Alternative

```r
nfile  Found 1 file

nfile  Found 3 files
```

### Two Alternatives

```r
ndir  Found 1 directory

ndir  Found 5 directories
```

### Three Alternatives (zero/one/many)

```r
nfile  Found 0 files: no files

nfile  Found 1 file: the file

nfile  Found 3 files: the files
```

### Helpers: qty() and no()

Use `no()` to display "no" instead of zero:

```r
nfile  Found no files
```

Use `qty()` to set quantity explicitly:

```r
nupd  3/10 files need updates
```

**For advanced pluralization**: See [references/inline-markup.md](references/inline-markup.md) for edge cases and complex patterns.

## CLI Conditions: Core Patterns

Use cli conditions instead of base R for better formatting:

### cli_abort() - Formatted Errors

```r
# Before (base R)
stop("File not found: ", path)

# After (cli)
cli_abort("File {.file {path}} not found")

# With bullets for context
check_file "` - Arrow/pointer

**For advanced error design**: See [references/conditions.md](references/conditions.md) for error design principles, rlang integration, testing strategies, and real-world patterns.

## Basic Progress Indicators

### Simple Progress Steps

```r
process_data % filter(mpg > 20)"
))

# Verbatim text (no formatting)
cli_verbatim("This is displayed exactly as-is: {not interpolated}")
```

### Lists

```r
# Unordered list
cli_ul()
cli_li("First item")
cli_li("Second item")
cli_end()

# Ordered list
cli_ol()
cli_li("First step")
cli_li("Second step")
cli_end()

# Definition list
cli_dl()
cli_li(c(name = "The name field"))
cli_li(c(email = "The email address"))
cli_end()
```

## Common Workflows

### Base R to CLI Migration

```r
# Before: Base R error handling
validate_input  0) {
    cli_abort(c(
      "Required column{?s} missing from data",
      "x" = "Missing {length(missing_cols)} column{?s}: {.field {missing_cols}}",
      "i" = "Data has {length(actual_cols)} column{?s}: {.field {actual_cols}}",
      "i" = "Add the missing column{?s} or check for typos"
    ))
  }

  invisible(data)
}
```

### Function with Progress Bar

```r
process_files <- function(files, verbose = TRUE) {
  n <- length(files)

  if (verbose) {
    cli_progress_bar(
      format = "Processing {cli::pb_bar} {cli::pb_current}/{cli::pb_total} [{cli::pb_eta}]",
      total = n
    )
  }

  results <- vector("list", n)

  for (i in seq_along(files)) {
    results[[i]] <- process_file(files[[i]])

    if (verbose) {
      cli_progress_update()
    }
  }

  results
}
```

## Resources & Advanced Topics

### Reference Files

- **[references/inline-markup.md](references/inline-markup.md)** - Complete catalog of inline classes organized by category, advanced patterns, nesting rules, and real-world examples

- **[references/conditions.md](references/conditions.md)** - Advanced error design patterns, rlang integration, testing with testthat snapshots, migration guide, and anti-patterns

- **[references/progress.md](references/progress.md)** - Nested progress bars, custom formats, all progress variables, parallel processing, Shiny integration, and debugging

- **[references/themes.md](references/themes.md)** - Complete theming system with CSS-like selectors, container functions, color palettes, custom themes, and accessibility

- **[references/ansi-operations.md](references/ansi-operations.md)** - ANSI string operations (align, columns, nchar, etc.), hyperlinks, color detection, testing CLI output, and troubleshooting

### External Resources

- [cli package documentation](https://cli.r-lib.org)
- [cli GitHub repository](https://github.com/r-lib/cli)
- [Building a semantic CLI (article)](https://cli.r-lib.org/articles/semantic-cli.html)

### Related Packages

- **rlang** - Condition handling and error objects integrate with cli
- **glue** - String interpolation powers cli's `{}` syntax
- **testthat** - Snapshot testing for cli output

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [posit-dev](https://github.com/posit-dev)
- **Source:** [posit-dev/skills](https://github.com/posit-dev/skills)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-posit-dev-skills-cli
- Seller: https://agentstack.voostack.com/s/posit-dev
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.