Built-in tools

Kiro's agent includes built-in tools for development tasks. These are provided by the unified agent harness and shared across surfaces. The default agent has access to all built-in tools - custom agents can restrict this.

At a glance:


Cross-surface	File read/write, shell, web search/fetch, sub-agents, context, task tracking, introspect
IDE and CLI	Hook creation
IDE and Web	Powers (`kiro_powers`)
IDE only	Background processes (dev servers), editor code analysis (`read_code`, semantic rename)
CLI only	Code intelligence (`code`), goal, session settings, MCP tool search (`tool_search`), knowledge (experimental), thinking (experimental)
Deprecated	`aws`, `delegate` - being replaced
Configuration	Use custom agents `tools` field + permissions

Tool catalog

All tools below are available across IDE, CLI, Web, and Mobile.

Tool	Category	Description
`read_file` / `read_files`	File	Read single or multiple files
`list_directory`	File	List directory contents
`file_search`	File	Fuzzy file path search (glob)
`grep_search`	File	Regex content search
`fs_write`	File	Create or overwrite a file
`fs_append`	File	Append to an existing file
`str_replace`	File	Targeted text replacement
`delete_file`	File	Delete a file
`execute_bash`	Shell	Run a shell command
`web_search`	Web	Search the web
`web_fetch`	Web	Fetch content from a URL
`invoke_subagent`	Agent	Delegate tasks in parallel
`disclose_context`	Context	Activate skills or steering
`introspect`	Context	Answer questions about Kiro's own features from official docs
`todo_list`	Session	Track tasks within a session

Surface availability

Some tools aren't available on every surface yet:

Tool	IDE	CLI	Web	Mobile	Status
`control_bash_process`	✓	—	—	—	GA
`get_process_output`	✓	—	—	—	GA
`list_processes`	✓	—	—	—	GA
`kiro_powers`	✓	—	✓	—	GA
`create_hook`	✓	✓	—	—	GA
`code`	—	✓	—	—	GA
`goal`	—	✓	—	—	GA
`session_settings`	—	✓	—	—	GA
`tool_search`	—	✓	—	—	GA
`knowledge`	—	✓	—	—	Experimental
`thinking`	—	✓	—	—	Experimental
`aws`	—	✓	—	—	Deprecated
`delegate`	—	✓	—	—	Deprecated → use sub-agents

The background-process tools (control_bash_process, get_process_output, list_processes) power the IDE's dev servers workflow. The code tool (tree-sitter and LSP-based code intelligence) is provided to non-IDE clients; in the IDE, equivalent capabilities are built in as editor-native tools - read_code for AST analysis and semantic rename - riding the language servers the editor already runs.

Configuring tool access

Use the tools field of a custom agent to control which tool categories are available:

json

{
  "tools": ["read", "write", "shell", "web"]
}

Each category maps to a set of tools:

Category	Includes
`read`	read_file, read_files, list_directory, file_search, grep_search, code
`write`	fs_write, fs_append, str_replace, delete_file
`shell`	execute_bash, control_bash_process, get_process_output, list_processes
`web`	web_fetch, web_search
`subagent`	invoke_subagent
`spec`	Spec workflow tools
`context`	disclose_context, introspect, knowledge

Special values:

Value	Effect
`@builtin`	All built-in tools
`@mcp`	All MCP server tools
`*`	Everything (built-in + MCP)

Exclude specific categories: "excludedTools": ["web"]

Control what tools can do (not just which are visible) with permissions.

File tools (read)

Tool	Description
`read_file`	Read a single file (text or image). Aliases: `fs_read`
`read_files`	Read multiple files with optional line ranges
`list_directory`	List directory contents in long format
`file_search`	Fuzzy file path search (glob patterns). Aliases: `glob`
`grep_search`	Regex content search across files. Aliases: `grep`
`code`	AST-based code analysis - signatures, symbols, fuzzy search

All read tools respect .kiroignore patterns and permissions fs_read capability rules.

File tools (write)

Tool	Description
`fs_write`	Create or overwrite a file. Aliases: `write`
`fs_append`	Append content to the end of an existing file
`str_replace`	Replace exact text in a file (targeted edits)
`delete_file`	Delete a file

Write tools respect permissions fs_write capability rules.

Shell tools

Tool	Description	Surfaces
`execute_bash`	Run a shell command. Aliases: `shell`, `execute_cmd`	IDE · CLI · Web
`control_bash_process`	Start/stop long-running background processes	IDE · CLI
`get_process_output`	Read output from a background process	IDE · CLI
`list_processes`	List running background processes	IDE · CLI

Shell tools respect permissions shell capability rules. Use match patterns to pre-approve common commands:

yaml

rules:
  - capability: shell
    match: ["git *", "npm *", "cargo *"]
    effect: allow
  - capability: shell
    match: ["rm -rf *", "sudo *"]
    effect: deny

Web tools

Detailed guide →

Tool	Description
`web_search`	Search the web for current information
`web_fetch`	Fetch and extract text content from a URL

Limitations: 10 MB max per fetch, 30s timeout, text/HTML only, 3 retries.

Enterprise administrators can disable web tools from Settings > Shared settings. See Enterprise governance - Web tools.

Code intelligence

Detailed guide →

Tree-sitter based code understanding for 18 languages - symbol search, document symbols, pattern search, and AST-based rewriting. Optional LSP integration for find references, go-to-definition, rename, and diagnostics.

Supported languages: Bash, C, C++, C#, Elixir, Go, Java, JavaScript, Kotlin, Lua, PHP, Python, Ruby, Rust, Scala, Swift, TSX, TypeScript

Sub-agent delegation

Tool	Description
`invoke_subagent`	Delegate a task to an agent running in isolated context

See Invoking as sub-agents for the full guide.

Context tools

Tool	Description
`disclose_context`	Activate skills or steering files into context
`introspect`	Search indexed Kiro documentation (semantic + BM25)
`knowledge`	Search indexed knowledge bases (experimental)

Tool search (CLI)

Detailed guide →

Loads MCP tools on demand instead of including every tool definition in every request. Keeps context efficient with many MCP servers. Available in the CLI.

How it works: Index → deferred compact list → on-demand tool_search call → activate matched tool.

Parameter	Type	Description
`tool_id`	string	Exact `server_name::tool_name` identifier
`query`	string	Keywords for BM25 search
`max_results`	integer	Max results (default: 5)

Enable in CLI: kiro-cli settings toolSearch.enabled true

Setting	Default	Description
`toolSearch.enabled`	`false`	Master toggle
`toolSearch.minPct`	`5`	Activate when tool specs exceed this % of context
`toolSearch.minTokens`	`50000`	Activate when tool specs exceed this token count

Session tools

Tool	Description	Status
`todo_list`	Track tasks within a session (create, complete, list)	GA
`create_hook`	Create agent hooks from chat	GA
`kiro_powers`	List, activate, and use installed powers	GA

Next steps

Web tools - detailed guide
Code intelligence - detailed guide
Custom agents - configure which tools agents can access
Permissions - control what tools can do
MCP - extend with external tools
Configuration scopes - where tool settings are stored

Page updated: August 4, 2026

Checkpoints and rewind

Web tools

At a glance:


Cross-surface	File read/write, shell, web search/fetch, sub-agents, context, task tracking, introspect
IDE and CLI	Hook creation
IDE and Web	Powers (`kiro_powers`)
IDE only	Background processes (dev servers), editor code analysis (`read_code`, semantic rename)
CLI only	Code intelligence (`code`), goal, session settings, MCP tool search (`tool_search`), knowledge (experimental), thinking (experimental)
Deprecated	`aws`, `delegate` - being replaced
Configuration	Use custom agents `tools` field + permissions

Tool catalog

All tools below are available across IDE, CLI, Web, and Mobile.

Tool	Category	Description
`read_file` / `read_files`	File	Read single or multiple files
`list_directory`	File	List directory contents
`file_search`	File	Fuzzy file path search (glob)
`grep_search`	File	Regex content search
`fs_write`	File	Create or overwrite a file
`fs_append`	File	Append to an existing file
`str_replace`	File	Targeted text replacement
`delete_file`	File	Delete a file
`execute_bash`	Shell	Run a shell command
`web_search`	Web	Search the web
`web_fetch`	Web	Fetch content from a URL
`invoke_subagent`	Agent	Delegate tasks in parallel
`disclose_context`	Context	Activate skills or steering
`introspect`	Context	Answer questions about Kiro's own features from official docs
`todo_list`	Session	Track tasks within a session

Surface availability

Some tools aren't available on every surface yet:

Tool	IDE	CLI	Web	Mobile	Status
`control_bash_process`	✓	—	—	—	GA
`get_process_output`	✓	—	—	—	GA
`list_processes`	✓	—	—	—	GA
`kiro_powers`	✓	—	✓	—	GA
`create_hook`	✓	✓	—	—	GA
`code`	—	✓	—	—	GA
`goal`	—	✓	—	—	GA
`session_settings`	—	✓	—	—	GA
`tool_search`	—	✓	—	—	GA
`knowledge`	—	✓	—	—	Experimental
`thinking`	—	✓	—	—	Experimental
`aws`	—	✓	—	—	Deprecated
`delegate`	—	✓	—	—	Deprecated → use sub-agents

Configuring tool access

Use the tools field of a custom agent to control which tool categories are available:

json

{
  "tools": ["read", "write", "shell", "web"]
}

Each category maps to a set of tools:

Category	Includes
`read`	read_file, read_files, list_directory, file_search, grep_search, code
`write`	fs_write, fs_append, str_replace, delete_file
`shell`	execute_bash, control_bash_process, get_process_output, list_processes
`web`	web_fetch, web_search
`subagent`	invoke_subagent
`spec`	Spec workflow tools
`context`	disclose_context, introspect, knowledge

Special values:

Value	Effect
`@builtin`	All built-in tools
`@mcp`	All MCP server tools
`*`	Everything (built-in + MCP)

Exclude specific categories: "excludedTools": ["web"]

Control what tools can do (not just which are visible) with permissions.

File tools (read)

Tool	Description
`read_file`	Read a single file (text or image). Aliases: `fs_read`
`read_files`	Read multiple files with optional line ranges
`list_directory`	List directory contents in long format
`file_search`	Fuzzy file path search (glob patterns). Aliases: `glob`
`grep_search`	Regex content search across files. Aliases: `grep`
`code`	AST-based code analysis - signatures, symbols, fuzzy search

All read tools respect .kiroignore patterns and permissions fs_read capability rules.

File tools (write)

Tool	Description
`fs_write`	Create or overwrite a file. Aliases: `write`
`fs_append`	Append content to the end of an existing file
`str_replace`	Replace exact text in a file (targeted edits)
`delete_file`	Delete a file

Write tools respect permissions fs_write capability rules.

Shell tools

Tool	Description	Surfaces
`execute_bash`	Run a shell command. Aliases: `shell`, `execute_cmd`	IDE · CLI · Web
`control_bash_process`	Start/stop long-running background processes	IDE · CLI
`get_process_output`	Read output from a background process	IDE · CLI
`list_processes`	List running background processes	IDE · CLI

Shell tools respect permissions shell capability rules. Use match patterns to pre-approve common commands:

yaml

rules:
  - capability: shell
    match: ["git *", "npm *", "cargo *"]
    effect: allow
  - capability: shell
    match: ["rm -rf *", "sudo *"]
    effect: deny

Web tools

Detailed guide →

Tool	Description
`web_search`	Search the web for current information
`web_fetch`	Fetch and extract text content from a URL

Limitations: 10 MB max per fetch, 30s timeout, text/HTML only, 3 retries.

Enterprise administrators can disable web tools from Settings > Shared settings. See Enterprise governance - Web tools.

Code intelligence

Detailed guide →

Supported languages: Bash, C, C++, C#, Elixir, Go, Java, JavaScript, Kotlin, Lua, PHP, Python, Ruby, Rust, Scala, Swift, TSX, TypeScript

Sub-agent delegation

Tool	Description
`invoke_subagent`	Delegate a task to an agent running in isolated context

See Invoking as sub-agents for the full guide.

Context tools

Tool	Description
`disclose_context`	Activate skills or steering files into context
`introspect`	Search indexed Kiro documentation (semantic + BM25)
`knowledge`	Search indexed knowledge bases (experimental)

Tool search (CLI)

Detailed guide →

Loads MCP tools on demand instead of including every tool definition in every request. Keeps context efficient with many MCP servers. Available in the CLI.

How it works: Index → deferred compact list → on-demand tool_search call → activate matched tool.

Parameter	Type	Description
`tool_id`	string	Exact `server_name::tool_name` identifier
`query`	string	Keywords for BM25 search
`max_results`	integer	Max results (default: 5)

Enable in CLI: kiro-cli settings toolSearch.enabled true

Setting	Default	Description
`toolSearch.enabled`	`false`	Master toggle
`toolSearch.minPct`	`5`	Activate when tool specs exceed this % of context
`toolSearch.minTokens`	`50000`	Activate when tool specs exceed this token count

Session tools

Tool	Description	Status
`todo_list`	Track tasks within a session (create, complete, list)	GA
`create_hook`	Create agent hooks from chat	GA
`kiro_powers`	List, activate, and use installed powers	GA

Next steps

Web tools - detailed guide
Code intelligence - detailed guide
Custom agents - configure which tools agents can access
Permissions - control what tools can do
MCP - extend with external tools
Configuration scopes - where tool settings are stored

Page updated: August 4, 2026

Checkpoints and rewind

Web tools