Built-in Tools

Flux exposes these tools to its agent loop.

Tool	Purpose
read_file	Read text ranges and preview images, PDFs, and Office documents
write_file	Create or replace a file
edit_file	Replace one exact, unique string in a file
find_files	Find names and glob matches
grep_search	Search file contents with regular expressions
list_directory	List a directory
overview	Map a repository's directory and symbol structure
run_command	Execute a shell command with sandbox detection
run_tests	Detect and run a supported project test framework
lsp_query	Request definitions, references, or hover data from a language server; diagnostic notifications are not yet fully surfaced
read_notebook	Read Jupyter notebook cells
edit_notebook	Change a notebook cell or its type
web_search	Search the web with DuckDuckGo
fetch_url	Send an HTTP request and return the response
github	Create or view GitHub pull requests and issues
update_plan	Update the active plan's current step
save_memory	Persist durable project or user context
subagent	Delegate an independent task

Connected MCP servers, installed plugins, and active skills can add more tools.

#Language-server navigation

The lsp_query tool can find definitions, references, and hover information in TypeScript, JavaScript, Python, Rust, and Go projects when the matching language-server executable is available.

Language	Executable
TypeScript or JavaScript	typescript-language-server
Python	pylsp
Rust	rust-analyzer
Go	gopls

Ask Flux for semantic evidence explicitly when a text search is not enough:

@scraper/__init__.py find the scraper registry.
Use definitions and references to trace where it is declared and called.
Explain the flow in execution order. Do not change files.

Flux combines language-server results with file reads and repository search. If the server is unavailable, confirm that its executable is on PATH in the shell that started Flux. Diagnostic notifications are not yet fully surfaced, so use the project's normal diagnostic command when complete output matters.

#Confirmations and undo

Writes, edits, and sensitive commands can display a confirmation prompt. Edit confirmations include a diff. Choosing the session-wide approval option releases queued confirmations as well.

Flux records prior content for tracked file edits in an in-memory undo stack:

/undo list
/undo

The stack contains up to twenty changes and does not survive process exit. A newly created file has no previous content to restore.

#Shell execution

Shell commands have a 30-second default timeout and bounded output. Flux auto-detects macOS Seatbelt or Linux Bubblewrap; Docker can be requested as a tool override. When no backend is available, the command runs unsandboxed with secret-like environment variables filtered out. Review security before using auto-accept mode.