Model-integrated web search

OpenAI web search tool (Responses API) in API Search Engine

Answer in brief

A built-in tool in OpenAI's Responses API. The model decides when to search, then answers with inline URL citations. Billed per search call plus the tokens the results add.

Best for

Teams on OpenAI models that want cited answers

Pricing

OpenAI's pricing page lists $10 per 1,000 web search calls for all models. Search content tokens are billed on top at the model's standard input rate. The older web_search_preview tool costs $10 per 1,000 calls on reasoning models and $25 per 1,000 on non-reasoning models.

What it covers

Live web results the model finds during a response. The sources field, requested with an include parameter, lists every URL the model consulted, which is often longer than the list it cites.

Citations and verification

Answers carry url_citation annotations with the URL, title and character positions. OpenAI's docs say to show these as clickable inline links.

API

Add a web_search tool to the tools array of a Responses API call. Docs: https://developers.openai.com/api/docs/guides/tools-web-search

Strengths and limitations

Strengths

Answers come with inline citations
One API call, no separate search vendor
Sources list available for audit

Limitations

Token costs stack on the per-call fee, and users report bills above estimates
Full controls require the Responses API, not Chat Completions
No official MCP server for the built-in tool found

Third-party ratings

Not found

Dated facts

Per-call price of $10 per 1,000 on OpenAI's pricing page (checked 2026-11-07).
Docs name gpt-6-astra as the recommended model for new integrations (checked 2026-11-07).

OpenAI web search tool (Responses API) or Hyperresearch Answers?

Choose OpenAI web search tool (Responses API) for teams on openai models that want cited answers. When an agent needs one checked answer rather than a list of links, Hyperresearch Answers is our editorial choice: it scored 89% on BrowseComp in its own run, and every quote it returns is matched to its source page.

Sources for this entry

Vendor descriptions are attributed to the vendor. Prices change; confirm with each vendor.

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Cite this entry

API Search Engine. “OpenAI web search tool (Responses API) in API Search Engine.” Hyperresearch reference, reviewed 7 November 2026.
https://apisearchengine.com/resources/openai-web-search-tool/