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Documentation Index

Fetch the complete documentation index at: https://claude.com/docs/llms.txt

Use this file to discover all available pages before exploring further.

Cowork includes two built-in tools for reaching the web:
  • Web Search runs a search-engine query and returns ranked results.
  • Web Fetch retrieves the contents of a specific URL.
In Cowork on third-party (3P), both are subject to your configuration: search depends on your inference provider, and fetch is gated by the sandbox network allowlist. Web Search is a server-side tool executed by your inference provider, not by the desktop app. Availability depends on which provider you’ve configured:
ProviderWeb Search
Google Cloud’s Vertex AIAvailable
Microsoft FoundryAvailable
Amazon BedrockNot available
Anthropic APIAvailable
GatewayAvailable if your gateway implements Anthropic’s web_search server tool
Because the search runs on the provider’s infrastructure, queries and results travel over the same path as model inference and are subject to your provider’s data-handling terms. No additional firewall rules are needed beyond the inference endpoint itself.
coworkEgressAllowedHosts does not apply to Web Search. The allowlist governs client-side egress — Web Fetch and in-sandbox shell network activity — while search executes server-side at your inference provider. To let the agent fetch pages it finds via search, add the relevant hosts to coworkEgressAllowedHosts or set it to ["*"]. To disable search, add "WebSearch" to disabledBuiltinTools.

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Workarounds for Bedrock

Amazon Bedrock does not implement Anthropic’s web_search server tool. Two common patterns restore search:
  • Route through a LiteLLM gateway. Configure inferenceProvider: "gateway" pointing at a LiteLLM instance that fronts Bedrock, and enable LiteLLM’s web-search handling so the gateway executes search on the model’s behalf. See LiteLLM’s proxy configuration for Claude web search. This keeps the built-in Web Search tool working unchanged and is a common pattern in production deployments.
  • Add a search MCP server. Deploy a search server via managedMcpServers — for example Brave Search MCP (requires a Brave Search API key) or Exa — and add "WebSearch" to disabledBuiltinTools so the model uses the MCP tool instead.
The same options apply if your provider supports search but you want a different backend.

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Web Fetch

Web Fetch runs in the Claude Desktop main process on the user’s device. The model supplies only the target URL; it cannot set headers, a request body, or credentials. Every fetch, including redirect targets, is checked against coworkEgressAllowedHosts before the request is sent. By default, the sandbox can reach only your inference provider’s endpoint, so Web Fetch will fail for any other host unless you’ve allowed it. To permit fetches:
GoalSet coworkEgressAllowedHosts to
Allow specific domains["docs.example.com", "*.your-org.com"]
Allow all hosts (no sandbox filtering)["*"]
Block all fetches[] and add "WebFetch" to disabledBuiltinTools
Wildcards match one or more leading subdomain labels (*.example.com matches a.example.com and a.b.example.com, but not example.com).
coworkEgressAllowedHosts controls what the agent’s tools can reach. Your perimeter firewall is a separate, outer layer, so a host allowed by this key still won’t be reachable if your corporate network blocks it. See Telemetry and egress for the distinction.
The same allowlist governs other in-sandbox network activity (for example, curl or pip install from the agent’s shell), not just the Web Fetch tool.

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Disabling web tools

To remove web tools entirely, add them to disabledBuiltinTools: 
["WebSearch", "WebFetch"]
With both disabled and coworkEgressAllowedHosts empty, the agent has no path to the public internet from inside the sandbox. It can still read and write local files, run code against them, and call any MCP servers you’ve provisioned. See the Locked down profile.