Built-in tools

harness.tools adds built-in tools for one invocation. Its value is a comma-separated string of tool names, such as "web_search,web_fetch". It does not accept tool objects, function arguments, or Python import paths

Version and scope

This page describes AgentKit CLI 0.54.0 with its default VeADK 1.0.8 dependency. This version exposes 13 tools by name, listed below. Every entry is an individual tool, not a toolset containing multiple tools Request-level tools is available on non-shared-OAuth Harness deployments through POST /harness/invoke and POST /run_sse requests carrying a harness configuration. Shared OAuth Harness deployments do not expose general request-level tool, model, or prompt overrides. These fields cannot add temporary tools to those deployments. The deployment’s TOOLS configuration defines its base tools. If it is unset or empty, none of the tools on this page are loaded by name Supported names depend on the VeADK version installed on the server. For custom images or manually upgraded dependencies, check the actual runtime before using a name

Supported tools

A registered name does not mean its cloud service, credentials, or sandbox is ready. Configure the environment variables below on the Harness server, not inside the HTTP request’s tools field

Name	Purpose	Requirements
`web_search`	Search the web and return summaries of matching pages	Volcengine web search with valid AK/SK or execution-role credentials; see the BytePlus conditions below
`parallel_web_search`	Run multiple web searches concurrently and return results by query	Volcengine web search with the same credentials as `web_search`; this version does not switch to the BytePlus search service
`web_fetch`	Fetch public pages as Markdown or plain text; also extract PDF text	No additional API key; the target public URL must be reachable, and PDF extraction requires `pypdf`; does not execute JavaScript or access private network addresses
`vesearch`	Search the web, social media, and news and return a summary	An enabled search agent, `TOOL_VESEARCH_ENDPOINT`, and valid service credentials; set `TOOL_VESEARCH_API_KEY` explicitly if needed
`link_reader`	Read titles and content from web pages, PDFs, or Douyin videos	Volcengine Ark LinkReader access and valid Ark credentials, optionally supplied as `MODEL_AGENT_API_KEY`; at most 3 URLs per call
`run_code`	Execute Python or Bash in an AgentKit sandbox and return the result	An available code sandbox, `AGENTKIT_TOOL_ID_SCRIPT`, and sandbox invocation credentials; falls back to `AGENTKIT_TOOL_ID` when the specific ID is unset
`coding`	Delegate a coding task to a preconfigured OpenCode sandbox	An AgentKit sandbox configured with OpenCode, `AGENTKIT_TOOL_ID_OPENCODE`, and sandbox invocation credentials; falls back to `AGENTKIT_TOOL_ID` when the specific ID is unset
`image_generate`	Generate one or more images from prompts and reference images	Access to an available image-generation model; configure `MODEL_IMAGE_API_KEY`, `MODEL_IMAGE_NAME`, and `MODEL_IMAGE_API_BASE` as needed
`image_edit`	Edit source images from prompts, including batch tasks	Access to an available image-editing model; configure `MODEL_EDIT_API_KEY`, `MODEL_EDIT_NAME`, and `MODEL_EDIT_API_BASE` as needed
`video_generate`	Generate videos from text, first/last frames, or multimodal references, including batch tasks	Access to an available video-generation model; configure `MODEL_VIDEO_API_KEY`, `MODEL_VIDEO_NAME`, and `MODEL_VIDEO_API_BASE` as needed
`text_to_speech`	Synthesize PCM audio from text and return its server-side path	An enabled speech synthesis service, `TOOL_VESPEECH_APP_ID`, and valid speech credentials; set `TOOL_VESPEECH_API_KEY` explicitly if needed; see voice and output settings below
`get_city_weather`	Return fixed example weather for predefined cities	No service credentials; use English city names; demonstration data, not live weather
`get_location_weather`	Return randomly generated example weather	No service credentials; demonstration data, not live weather

To read PDFs, include pypdf in the Harness deployment dependencies and rebuild the image. Ordinary web-page extraction does not require this PDF parser

Search and sandbox credentials

Volcengine search prefers TOOL_WEB_SEARCH_ACCESS_KEY and TOOL_WEB_SEARCH_SECRET_KEY. It can also use VOLCENGINE_ACCESS_KEY and VOLCENGINE_SECRET_KEY, or the runtime’s execution-role credentials For BytePlus search, set CLOUD_PROVIDER=byteplus and BYTEPLUS_WEB_SEARCH_API_KEY. In VeADK 1.0.8, web_search still requires resolvable AK/SK or execution-role credentials. Set BytePlus AK/SK through BYTEPLUS_ACCESS_KEY and BYTEPLUS_SECRET_KEY. Do not assume that parallel_web_search also supports BytePlus search run_code and coding require permission to invoke the target sandbox. Use the runtime’s execution role or the appropriate cloud provider’s AK/SK. Configure the sandbox region with AGENTKIT_TOOL_REGION. With CLOUD_PROVIDER=byteplus, the default region is ap-southeast-1; the Volcengine default is cn-beijing

Images, video, and speech

When no dedicated API key is configured, image generation, image editing, and video generation reuse MODEL_AGENT_API_KEY or VeADK’s default model credentials. A valid tool name does not grant access to its generation model. The API URL, model name, and credentials must identify a compatible service. Uploading image results to TOS additionally requires DATABASE_TOS_BUCKET and valid TOS access credentials Set the speech voice with TOOL_VESPEECH_SPEAKER, which defaults to zh_female_vv_uranus_bigtts. Set the audio output directory with TOOL_VESPEECH_AUDIO_OUTPUT_PATH; by default, it uses the server’s temporary directory. The returned file path is not a public download URL

Search, sandbox execution, and media generation can incur cloud resource charges. Configure tool credentials and execution environments for the resources the agent is allowed to access

Input and merge behavior

`harness.tools` value	Behavior for this invocation
Field omitted	Keep the deployment’s existing tools
`""`, or only whitespace and commas	Add nothing and keep existing tools
`"web_search,web_fetch"`	Add these tools to the existing tools; do not add another tool with the same name
`" web_search, web_fetch "`	Trim whitespace around each name before loading
Unknown name or incorrect capitalization	Log a warning and skip that name; other loadable tools remain available
An array, object, or `null`	Fail request validation because the field requires a string

Request-level tools adds tools; it does not replace or clear deployment tools, and it does not persistently change the deployment configuration. A missing Python dependency or credential required during initialization also causes that tool to be skipped with a warning. Tools that load successfully can still fail during execution because of credentials, permissions, or external services tools selects the tools available to the agent. The agent supplies search queries, image tasks, code, and other tool arguments when calling a tool; these are not objects inside harness.tools. Making a tool available does not guarantee that the agent calls it on every request The following request adds two tools that do not require cloud service credentials to one invocation of a non-shared-OAuth Harness. The service still needs a working reasoning-model configuration

curl -X POST http://localhost:8000/harness/invoke \
  -H 'Content-Type: application/json' \
  -d '{
    "harness_name": "harness_app",
    "prompt": "Read https://example.com and report the example weather for Beijing",
    "harness": {
      "tools": "web_fetch,get_city_weather"
    },
    "run_agent_request": {
      "user_id": "demo-user",
      "session_id": "tools-demo"
    }
  }'

When calling through a cloud gateway, add authentication as required by that gateway. Server-side tool credentials and the HTTP caller’s gateway credentials are configured separately

MCP and skills

Field	Input	Purpose
`tools`	Comma-separated string of built-in tool names listed on this page	Load individual tools provided by VeADK
`mcp_servers`	List of MCP server configurations	Connect to remote MCP servers and discover and use their tools
`skills`	Comma-separated string of skill references	Load skill instructions and resources from a skill-hub path, a skill space, or one skill in a space

Names of MCP tools, skills, or arbitrary Python functions cannot be used directly in tools. Skill references such as clawhub/owner/skill, ss-..., and ss-...:s-... belong in skills, not the built-in tool list The VeADK 1.0.8 name list does not include video_task_query, ppt_generate, bash_toolset, or run_sandbox_agent. Availability through another VeADK interface does not make a capability loadable by the same name through this Harness field

Check the actual runtime

Run the following command inside the Python environment or container used by Harness to inspect its installed version and supported names. Running it in a different environment on your computer does not verify the deployed tool list

python - <<'PY'
from importlib.metadata import version
from veadk.tools import list_builtin_tools

print("VeADK:", version("veadk-python"))
for name in list_builtin_tools():
    print(name)
PY

list_builtin_tools() lists names supported by the installed version. It does not validate cloud permissions, credentials, or sandbox availability. If an expected tool is missing, check the version, name, and server-side loading warnings, then verify the tool’s runtime requirements

Agent API Server API

Harness Runtime API

Version and scope

Supported tools

Search and sandbox credentials

Images, video, and speech

Input and merge behavior

MCP and skills

Check the actual runtime

​Version and scope

​Supported tools

​Search and sandbox credentials

​Images, video, and speech

​Input and merge behavior

​MCP and skills

​Check the actual runtime

Version and scope

Supported tools

Search and sandbox credentials

Images, video, and speech

Input and merge behavior

MCP and skills

Check the actual runtime