# Web Search Tool

> A web search tool lets a language model issue search queries, read the results, and ground its answer in current web content, usually returning citations to the pages it used.

- Identifier: PTL-0137
- Category: Retrieval & Tool Use
- Canonical URL: https://protologue.com/t/web-search-tool/
- Also known as: web browsing, search grounding, grounding with search, browsing tool
- Introduced: 2021

## Description

Search is the main remedy for a model's knowledge cutoff and for questions about prices, news, and other changing facts. Early work trained a model to browse with a text-based browser and cite its sources. Today providers offer search as a built-in tool. Search results are untrusted input, so they are a vector for indirect prompt injection.

## Broader terms

- [Function Calling](https://protologue.com/t/function-calling/)

## Related terms

- [Knowledge Cutoff](https://protologue.com/t/knowledge-cutoff/)
- [Citation Generation](https://protologue.com/t/citation-generation/)
- [Retrieval-Augmented Generation](https://protologue.com/t/retrieval-augmented-generation/)
- [Indirect Prompt Injection](https://protologue.com/t/indirect-prompt-injection/)

## Sources

- Nakano et al. (2021). WebGPT: Browser-assisted question-answering with human feedback. https://arxiv.org/abs/2112.09332
- Anthropic (2025). Web search tool. https://platform.claude.com/docs/en/agents-and-tools/tool-use/web-search-tool

## Cite this entry

Protologue. (2026). Web Search Tool. In Protologue: A Taxonomy of Prompting and LLM Techniques (v1.4.0, PTL-0137). https://protologue.com/t/web-search-tool/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)