Web Search Server Tool

Use phaseo:web_search when the model needs current or source-backed information. The model decides when to search, writes the query, and can search multiple times in one request. Phaseo returns URLs, titles, snippets, highlights, and optional page text to the model so it can write a grounded response.

TinyFish Search is available as an optional managed engine. Provider-native search remains available through engine: "native" on supported routes.

How it works

Add { "type": "phaseo:web_search" } to tools.
The model decides whether it needs a search and emits a query.
Phaseo executes the search using the configured engine.
Results are returned to the model as tool context.
The model writes the final response and may search again if needed.

Quick start

curl https://api.phaseo.app/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-5-nano",
    "messages": [
      { "role": "user", "content": "What were the major AI announcements this week?" }
    ],
    "tools": [
      { "type": "phaseo:web_search" }
    ]
  }'

Configuration

{
  "type": "phaseo:web_search",
  "parameters": {
    "engine": "exa",
    "max_results": 5,
    "max_total_results": 15,
    "search_context_size": "medium",
    "max_characters": 2048,
    "allowed_domains": ["arxiv.org", "nature.com"],
    "excluded_domains": ["reddit.com"],
    "include_highlights": true,
    "include_text": false
  }
}

Parameter	Type	Default	Description
`engine`	string	`exa`	Search engine: `auto`, `native`, `exa`, `parallel`, `firecrawl`, `perplexity`, or `tinyfish`.
`max_results`	integer	`5`	Maximum results returned per search call.
`max_total_results`	integer	`10`	Maximum cumulative results across the server-tool loop.
`max_uses`	integer	`10`	Maximum search calls across the server-tool loop.
`search_context_size`	string	`medium`	Context size for engines that support highlight sizing: `low`, `medium`, or `high`.
`max_characters`	integer	engine default	Maximum text characters per result when text is included.
`allowed_domains`	string[]	none	Only return results from these domains. Alias: `include_domains`.
`excluded_domains`	string[]	none	Exclude results from these domains. Alias: `exclude_domains`.
`include_highlights`	boolean	`true`	Include engine-provided highlights/snippets when available.
`include_text`	boolean	`false`	Include fuller result text when the engine supports it.
`user_location`	object	none	Optional location hint for engines that support localized search.
`language`	string	none	TinyFish language hint, such as `en`.
`page`	integer	`0`	TinyFish result page, from `0` through `10`.

Engine selection

Engine	Behavior
`exa`	Managed Exa search. Requires Phaseo to have Exa configured for the gateway runtime.
`auto`	Uses the configured managed default, currently Exa.
`parallel`	Uses Parallel search when configured.
`firecrawl`	Uses Firecrawl search when configured.
`perplexity`	Uses the first-party Perplexity Search API when configured. Supports ranked results, `search_context_size`, regional search from `user_location.country`, and either allowed or excluded domains.
`tinyfish`	Uses TinyFish Search when `TINYFISH_API_KEY` is configured. Supports localized, paginated ranked results and translates `allowed_domains` / `excluded_domains` into search operators. TinyFish Search does not supply full page text; use `phaseo:web_fetch` when fuller content is needed.
`native`	Converts the declaration to a provider-native web-search tool before the upstream model call when the request surface supports it. On Chat Completions and Responses, the request goes only to providers that run web search themselves; if none serve the model, Phaseo runs its default search engine instead and bills it as a managed search.

Use engine: "native" only in the tool declaration. If a model tries to pass engine: "native" inside an already-emitted gateway search call, Phaseo returns a tool error because native tools must be selected before the upstream request is sent.

TinyFish Search

Enable the engine by configuring TINYFISH_API_KEY in your Phaseo gateway runtime secrets, then select it in the tool parameters:

{
  "type": "phaseo:web_search",
  "parameters": {
    "engine": "tinyfish",
    "language": "en",
    "page": 0,
    "max_results": 5,
    "allowed_domains": ["phaseo.app", "github.com"],
    "excluded_domains": ["reddit.com"]
  }
}

language provides a locale hint and page selects a result page from 0 through 10. TinyFish supports both domain-filter lists; Phaseo converts them into search operators. Results include URLs, titles, and snippets/highlights. Use phaseo:web_fetch when the model needs fuller text from a result.

Domain filtering

Use allowed_domains when the answer must come from a controlled source set:

{
  "type": "phaseo:web_search",
  "parameters": {
    "allowed_domains": ["phaseo.app", "github.com"]
  }
}

Use excluded_domains when broad web search is allowed but specific domains should be removed from the result set. Perplexity and Firecrawl accept either allowed_domains or excluded_domains in a single search call, not both. Perplexity accepts up to 20 domain filters per request and maps excluded domains to its denylist format. TinyFish translates both arrays to site: and -site: operators in the query. TinyFish Search is free on its published plans, so Phaseo does not add a provider usage charge for engine: "tinyfish"; normal Phaseo request and token pricing still applies.

Responses API

The same tool shape works with /v1/responses:

{
  "model": "openai/gpt-5-nano",
  "input": "Find the latest release notes for Phaseo.",
  "tools": [
    { "type": "phaseo:web_search", "parameters": { "max_results": 4 } }
  ]
}

Usage and pricing

Web search calls increment:

{
  "usage": {
    "server_tool_use": {
      "web_search_requests": 1,
      "web_search_results": 5,
      "web_search_extra_results": 0
    }
  }
}

Managed search pricing can use server_tool_web_search_requests and server_tool_web_search_extra_results. Provider-native search usage can use native_web_search_requests where a model price card defines that meter.

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Web Search Server Tool

How it works

Quick start

Configuration

Engine selection

TinyFish Search

Domain filtering

Responses API

Usage and pricing

​How it works

​Quick start

​Configuration

​Engine selection

​TinyFish Search

​Domain filtering

​Responses API

​Usage and pricing

​Related

How it works

Quick start

Configuration

Engine selection

TinyFish Search

Domain filtering

Responses API

Usage and pricing

Related