Built-in Skills

Definable ships 9 built-in skills that cover common agent needs. Each provides domain instructions and pre-configured tools.

from definable.skill import Calculator, DateTime, TextProcessing
from definable.skill import FileOperations, HTTPRequests, JSONOperations
from definable.skill import Shell, WebSearch
from definable.skill import MacOS  # macOS control via Desktop Bridge

Calculator

Safe math evaluation via AST parsing. Supports arithmetic, functions (sqrt, log, sin, cos, factorial, etc.), and constants (pi, e).

from definable.skill import Calculator

agent = Agent(model=model, skills=[Calculator()])
agent.run("What is sqrt(144) + 2^8?")

Tools: calculate(expression)

DateTime

Current date/time with timezone support and date difference calculations.

from definable.skill import DateTime

agent = Agent(model=model, skills=[DateTime()])
agent.run("What time is it in UTC+5:30?")

Tools: get_current_time(timezone_name=), date_difference(date1, date2)

TextProcessing

Regex search/replace, text statistics, transformations, and pattern extraction (emails, URLs, phone numbers, etc.).

from definable.skill import TextProcessing

agent = Agent(model=model, skills=[TextProcessing()])
agent.run("Extract all email addresses from this text: ...")

Tools: regex_search, regex_replace, text_stats, text_transform, extract_patterns

FileOperations

Sandboxed file reading, writing, listing, and appending.

from definable.skill import FileOperations

agent = Agent(
  model=model,
  skills=[FileOperations(base_dir="./data", allow_write=False)],
)
agent.run("List all files in the data directory")

str

default:"."

Root directory. All paths are sandboxed to this location.

bool

default:true

Enable write_file and append_to_file tools. Set to False for read-only access.

int

default:1048576

Maximum file read size in bytes (default: 1 MB).

Tools: read_file, list_files, write_file (if writable), append_to_file (if writable)

HTTPRequests

Make HTTP calls with optional domain restrictions.

from definable.skill import HTTPRequests

agent = Agent(
  model=model,
  skills=[HTTPRequests(allowed_domains={"api.example.com"})],
)
agent.run("GET https://api.example.com/users")

Set[str]

Domain allowlist. Empty or None allows all domains.

int

default:30

Request timeout in seconds.

Dict[str, str]

Headers included in every request.

Tools: http_get, http_post, http_put, http_patch, http_delete

JSONOperations

Parse, query (dot notation + wildcards), transform, and diff JSON data.

from definable.skill import JSONOperations

agent = Agent(model=model, skills=[JSONOperations()])
agent.run('Extract the name from: {"users": [{"name": "Alice"}]}')

Tools: parse_json, query_json, transform_json, compare_json Query paths support dot notation (users.0.name), array indices, and wildcards (items.*.id).

Shell

Execute shell commands with safety controls.

from definable.skill import Shell

agent = Agent(
  model=model,
  skills=[Shell(allowed_commands={"ls", "cat", "grep", "wc"})],
)
agent.run("Count the lines in all Python files")

Set[str]

If set, only these base commands are allowed. Overrides blocked list.

Set[str]

Commands blocked by default: rm, sudo, kill, chmod, shutdown, and other destructive operations.

int

default:30

Command timeout in seconds.

str

Working directory for command execution.

Tools: run_command

WebSearch

Web search (DuckDuckGo by default) and URL content fetching.

from definable.skill import WebSearch

agent = Agent(model=model, skills=[WebSearch()])
agent.run("Search for the latest Python release notes")

int

default:5

Maximum search results to return.

Callable

Custom search function. Signature: (query: str, max_results: int) -> str. Default uses DuckDuckGo.

bool

default:true

Enable the fetch_url tool for reading web page content.

Tools: search_web, fetch_url (if enabled)

The default DuckDuckGo provider requires duckduckgo-search, which is lazy-imported at first use.

MacOS

Control a Mac like a human: screen capture, mouse/keyboard input, app management, file operations, AppleScript, and system info. Requires the Definable Desktop Bridge to be running.

from definable.skill import MacOS

agent = Agent(
  model=model,
  skills=[MacOS(allowed_apps={"Safari", "TextEdit"})],
)
agent.run("Open Safari and navigate to apple.com")

See the MacOS skill guide for setup, permissions, and the full tool reference. Tools (30 default): screenshot, read_screen, find_text_on_screen, click, type_text, press_key, scroll, drag, open_app, quit_app, activate_app, list_running_apps, open_url, list_windows, focus_window, find_element, get_ui_tree, click_element, set_element_value, read_file, list_files, write_file, move_file, get_clipboard, set_clipboard, run_applescript, system_info, get_battery, set_volume, send_notification Optional dep: pip install 'definable[desktop]' (adds websockets for DesktopInterface)

Summary

Skill	Tools	Optional Deps
`Calculator`	`calculate`	—
`DateTime`	`get_current_time`, `date_difference`	—
`TextProcessing`	`regex_search`, `regex_replace`, `text_stats`, `text_transform`, `extract_patterns`	—
`FileOperations`	`read_file`, `list_files`, `write_file`, `append_to_file`	—
`HTTPRequests`	`http_get`, `http_post`, `http_put`, `http_patch`, `http_delete`	—
`JSONOperations`	`parse_json`, `query_json`, `transform_json`, `compare_json`	—
`Shell`	`run_command`	—
`WebSearch`	`search_web`, `fetch_url`	`duckduckgo-search`
`MacOS`	30 tools (screen, input, apps, files, system, AppleScript)	`websockets` (optional, for `DesktopInterface`)

Get Started

Basics

Capabilities

Advanced

Calculator

DateTime

TextProcessing

FileOperations

HTTPRequests

JSONOperations

Shell

WebSearch

MacOS

Summary

​Calculator

​DateTime

​TextProcessing

​FileOperations

​HTTPRequests

​JSONOperations

​Shell

​WebSearch

​MacOS

​Summary

Calculator

DateTime

TextProcessing

FileOperations

HTTPRequests

JSONOperations

Shell

WebSearch

MacOS

Summary