Can a Perplexity Agent preset's search type be overridden?

Definition: Yes. A Perplexity Agent API request can keep a preset and set search_type on its web_search tool. That tool-level value controls the search path for the tool call and takes precedence over the preset's default.

Key facts

• The web_search tool searches the web during an Agent API request, and the model decides when to call it from the prompt and instructions. Perplexity's Web Search documentation describes this tool-level behavior.
• When search_type is omitted, the tool inherits the preset's search type when one is configured. Without a preset value, the tool uses "web". Perplexity's Web Search documentation states this defaulting rule.
• search_type: "fast" selects the lower-latency Fast Search path, while search_type: "web" selects standard web search. The documented Fast Search price is $1.00 per 1,000 invocations instead of $2.50, plus model tokens. Perplexity's Web Search documentation gives these settings and prices.
• The fast, low, medium, and high presets set search_type: "fast" by default. The xhigh preset uses "web". Perplexity's Web Search documentation lists these preset defaults.
• Preset fields supplied in the request override their defaults, and tools merge per tool. Listing web_search changes that tool's options while leaving the preset's other tools enabled. Perplexity's Presets documentation describes the merge rule.

How is the search type overridden?

The preset stays at the request level, and the override sits inside the web_search object in tools. For example, this request uses the low preset while selecting standard web search for its web search calls:

response = client.responses.create(
    preset="low",
    input="Summarize the latest changes to the Rust language.",
    tools=[
        {
            "type": "web_search",
            "search_type": "web"
        }
    ]
)

The same field can be set to "fast" when the request should use Fast Search. Perplexity's Web Search documentation places search_type in the tool object and says that passing it there overrides a preset's search type.

What happens when the field is omitted?

The tool follows a three-part defaulting rule. An explicit tool-level search_type is used first. If it is absent and the selected preset defines a search type, the tool inherits that preset value. If neither supplies one, the documented fallback is "web".

This makes omission different from an explicit override. For example, an omitted field on low follows that preset's documented "fast" default, while "web" in the web_search object selects standard web search for the tool call. The Web Search page also says that search_type is separate from the Agent API fast preset.

Does the override replace the whole preset?

No. Perplexity describes presets as bundles containing a model, search config, reasoning steps, system prompt, and available tools. Its customization rules say that fields supplied alongside a preset override that field's default, while fields left out retain the preset's default.

Tools have a narrower merge behavior. A web_search entry overrides that tool's options and leaves the preset's other tools enabled. Search depth can also be tuned under a preset with max_tokens and max_tokens_per_page on web_search, which are separate settings from search_type.

FAQ

Can a low preset use standard web search?

Yes. Add "search_type": "web" inside the web_search tool. The documented low default is "fast", so the explicit tool value changes the search path for that tool.

What value selects Fast Search?

Use "fast" as the value of search_type inside web_search. Perplexity describes this path as lower latency and lists a price of $1.00 per 1,000 invocations, plus model tokens.

Is search_type a preset name?

No. It is a field on the web_search tool. The Web Search documentation describes it as separate from the Agent API fast preset.

What should happen if you leave search_type out?

The tool inherits the selected preset's search type when available. Otherwise, it uses "web".

Related terms

• Perplexity
• When should a Perplexity Search API request use search_type=fast?
• How does Perplexity's Search API differ from its Agent API?

Sources

1. Perplexity, "Web Search", n.d.
2. Perplexity, "Presets", n.d.

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