Built-in Tools Reference

35 tools across 6 categories. Each tool is available via the composition functions in cersei::tools.

cersei::tools::all()           // all 35
cersei::tools::coding()        // filesystem + shell + web (11)
cersei::tools::filesystem()    // 6 tools
cersei::tools::shell()         // 2 tools
cersei::tools::web()           // 3 tools
cersei::tools::planning()      // 3 tools
cersei::tools::scheduling()    // 5 tools
cersei::tools::orchestration() // 9 tools

Filesystem

Read

Read a file with optional line offset and limit. Returns content with line numbers.

Permission: ReadOnly

Write

Write content to a file, creating parent directories if they don't exist.

Permission: Write

Edit

Exact string replacement in a file. Fails if the old string is not unique (unless replace_all is true).

Permission: Write

Glob

Find files matching a glob pattern, sorted by path.

Permission: ReadOnly

Grep

Search file contents using regex. Uses ripgrep if available, falls back to system grep.

Permission: ReadOnly

NotebookEdit

Edit a Jupyter notebook cell by index.

Permission: Write

Shell

Bash

Execute a shell command. Working directory and environment variables persist across calls within a session.

Permission: Execute

PowerShell

Execute a PowerShell command. Uses pwsh on macOS/Linux.

Permission: Execute

Web

WebFetch

Fetch a URL and return readable text. HTML is converted to plain text via html2text.

Permission: ReadOnly

WebSearch

Search the web via an API (Brave Search by default). Requires CERSEI_SEARCH_API_KEY.

Permission: ReadOnly

ExaSearch

AI-powered web search using Exa. Returns structured results with optional text content, highlights, and summaries. Requires EXA_API_KEY.

Permission: ReadOnly

Planning

EnterPlanMode

Switch to plan mode — restricts the agent to read-only tools for safe exploration.

Permission: None. No input required.

ExitPlanMode

Exit plan mode and return to full tool access.

Permission: None. No input required.

TodoWrite

Create and manage a structured task list with status tracking.

Permission: None

Scheduling

CronCreate

Schedule a recurring or one-shot prompt.

Permission: Execute

CronList

List all scheduled jobs with run counts.

Permission: None. No input required.

CronDelete

Delete a scheduled job by ID.

Permission: Execute

Sleep

Pause execution for a duration.

Permission: None

RemoteTrigger

Send an event to another session or agent.

Permission: Execute

Orchestration

SendMessage

Send a message to another agent or session.

Permission: None

TaskCreate

Create a new task for tracking work.

Permission: None

TaskGet

Get a task's current status, description, and output.

Permission: None

TaskUpdate

Update a task's status and/or output.

Permission: None

TaskList

List all tasks with their status.

Permission: None. No input required.

TaskStop

Stop a running task.

Permission: None

TaskOutput

Get the full output of a completed task.

Permission: None

EnterWorktree

Create an isolated git worktree for parallel branch work.

Permission: Write

ExitWorktree

Remove a git worktree and return to the original working directory.

Permission: Write

Other

AskUserQuestion

Ask the user a question and wait for their response.

Permission: None

SyntheticOutput

Return structured JSON for programmatic consumption. Used by coordinator mode and SDK integrations.

Permission: None

Config

Read or modify session-scoped configuration values.

Permission: None

Skill

Load and execute a skill (prompt template) from .claude/commands/, .claude/skills/, or bundled skills.

Permission: None

ToolSearch

Search for available tools by keyword.

Permission: None

Permission Summary