Wrap a Skill Directory as an MCP Tool Generator

Creates a closure that produces an ellmer::tool dispatching on an action enumerator:

readme: Returns the full SKILL.md instructions. Must be called first to unlock other actions.
reference: Returns content from a reference file in the skill directory (gated behind readme).
script: Executes a script in the scripts/ subdirectory via processx::run() (gated behind readme).

Usage

skill_wrapper(skill_path)

Arguments

skill_path: Path to the skill directory containing SKILL.md. Can be absolute or relative to the project root.

Value

A function with class c("shidashi_skill_wrapper", "function") that returns an ellmer::ToolDef object.

Details

The returned tool enforces a soft gate: calling reference or script before readme is allowed, but if the call errors the message is augmented with a condensed summary (~200 tokens) instructing the AI to read the full instructions first. This minimizes token waste (the summary is only sent on failure).

The gate state is per-instance: each call to the wrapper produces a closure with an independent readme_unlocked flag.

Examples

skill_dir <- system.file(
  "builtin-templates/bslib-bare/agents/skills/greet",
  package = "shidashi"
)
wrapper  <- skill_wrapper(skill_dir)
tool_def <- wrapper()
cat(tool_def(action = "readme"))
#> ## Instructions
#> 
#> This skill demonstrates the skill system. It runs a short R script
#> that prints a personalised greeting.
#> 
#> ### Usage
#> 
#> 1. Call `action='script'`, `file_name='greet.R'`, `args=['World']`
#> 2. The script prints: `Hello, World!`
#> 
#> ### Arguments
#> 
#> - `args[1]`: The name to greet (default: `"World"`)
#> 
#> ## Available scripts
#> - greet.R