showsignature

A CLI that extracts the useful structure from source files: signatures, imports, types, variables, comments, and Markdown sections.

Use it to understand a codebase quickly, review files, or create compact context for AI assistants.

Installation

Step 1. Add the skill

# install in pi
pi install npm:showsignature
pi install git:github.com/FredySandoval/showsignature
pi install https://github.com/FredySandoval/showsignature

# All agents
npx skills add https://github.com/FredySandoval/showsignature --skill showsignature

Step 2. Install locally or globally

# global install
npm install -g showsignature

# local install
npm install showsignature

From source for development:

git clone https://github.com/FredySandoval/showsignature.git
cd showsignature
pnpm install
pnpm build
pnpm link --global

# use without installing it
npx showsignature --help

Requires Node.js 18+.

Why?

Large files are noisy. showsignature gives you the shape of a project before you read the implementation:

• What functions/classes exist?
• What does each file import/export?
• What types and interfaces define the data?
• What headings/tables/code blocks exist in Markdown?

Usage

Option	Description
--file <file>	Inspect one file.
--folder <folder>	Inspect a folder.
--stdin	Read source from stdin.
--lang-only <lang>	Force language, useful with stdin.
--show-only <items>	Choose extractors.
--output <file>	Save output.
--include-tests	Include test files in folder scans.
--max-depth <n>	Limit folder scan depth.
--ignore-folder <name>	Skip folders.

Extractors

Code files:

Mode	Shows
signatures	Functions, classes, methods, constructors.
imports	Import statements.
interfaces	TypeScript/Go interfaces.
types	Type aliases/declarations.
variables	Variables/constants.
comments	Code comments.

Markdown files:

Mode	Shows
md:headings	Headings.
md:tables	Tables.
md:codeblocks	Fenced code blocks.
md:all	Full document.

Supported files

Language	Extensions
TypeScript	.ts, .mts, .cts
JavaScript	.js, .mjs, .cjs
Go	.go
Python	.py
Markdown	.md

Basic usage examples

showsignature [--file <file> | --folder <folder> | --stdin] [options]

showsignature --help                                        # Show available options
showsignature --file src/01-main.ts                         # Inspect one file
showsignature --folder ./src                                # Inspect a folder
showsignature --folder .                                    # Inspect the current directory
cat src/01-main.ts | showsignature --stdin --lang-only ts   # Read TypeScript from stdin

showsignature --folder . --show-only imports                # Show imports only
showsignature --folder ./src --show-only signatures,imports # Show code structure and imports
showsignature --folder ./src --show-only interfaces,types   # Show data shapes
showsignature --file src/01-main.ts --show-only variables   # Show variables

showsignature --file README.md --show-only md:headings      # Extract Markdown headings
showsignature --file README.md --show-only md:codeblocks    # Extract Markdown code blocks
showsignature --folder . --show-only md:tables              # Extract Markdown tables

showsignature --folder . --lang-only py                     # Process Python files only
showsignature --folder . --max-depth 2                      # Limit recursive scan depth
showsignature --folder . --ignore-folder dist               # Skip a noisy folder
showsignature --folder src --show-only signatures,imports --output structure.md # Save compact context

Combine modes with commas:

showsignature --folder src --show-only signatures,imports,comments

Pipeline usage

showsignature writes to stdout by default, so it works well with tools like rg, grep, fzf, less, head, tee, and shell redirects.

showsignature --folder src | rg "function|class" # Search extracted structure with ripgrep
showsignature --folder src --show-only imports | rg "node:" # Find matching imports
showsignature --folder src --show-only signatures | rg "async" # Find async functions or methods
showsignature --folder src --show-only comments,signatures | rg -C 2 "ExtractKind" # Search comments/signatures with nearby context
showsignature --folder src --show-only signatures,imports | less # Page through large output
showsignature --folder src --show-only signatures | head -50 # Preview the first 50 lines
showsignature --folder src --show-only signatures,imports | tee structure.md # View and save output

Development

pnpm install
pnpm build
pnpm test
pnpm typecheck
pnpm format

Troubleshooting

• Command not found? Use node dist/02-cli.js --help for local builds, or check your global npm bin path.
• Folder scan empty? Supported files only are scanned; .gitignore is respected; tests are skipped unless --include-tests is set.
• Stdin language unknown? Add --lang-only ts, --lang-only py, --lang-only go, or similar.

License

ISC. See LICENSE.