server: add Brave search provider

docker-compose.example.yml

@@ -17,6 +17,7 @@ services:
       HERMES_AGENT_API_KEY: ${HERMES_AGENT_API_KEY:-}
       HERMES_AGENT_MODEL: ${HERMES_AGENT_MODEL:-}
       EXA_API_KEY: ${EXA_API_KEY:-}
+      BRAVE_SEARCH_API_KEY: ${BRAVE_SEARCH_API_KEY:-}
       CHAT_WEB_SEARCH_ENGINE: ${CHAT_WEB_SEARCH_ENGINE:-exa}
       SEARXNG_BASE_URL: ${SEARXNG_BASE_URL:-}
       CHAT_MAX_TOOL_ROUNDS: ${CHAT_MAX_TOOL_ROUNDS:-100}

docs/api/rest.md

@@ -304,7 +304,7 @@ Behavior notes:
 - For `openai`, Responses calls that can enter the server-managed tool loop use `store: true` so reasoning and function-call items can be passed between tool rounds.
 - For `anthropic`, image attachments are sent as Messages API `image` blocks using base64 source data; text attachments are added as `text` blocks.
 - Available Sybil-managed tool calls for `openai`, `anthropic`, `xai`, and `gemini`: `web_search` and `fetch_url`. When `CHAT_CODEX_TOOL_ENABLED=true`, `codex_exec` is also available. When `CHAT_SHELL_TOOL_ENABLED=true`, `shell_exec` is also available.
-- `web_search` returns ranked results with per-result summaries/snippets. Its backend engine is selected by `CHAT_WEB_SEARCH_ENGINE` (`exa` default, or `searxng` with `SEARXNG_BASE_URL` set). SearXNG mode requires the instance to allow `format=json`.
+- `web_search` returns ranked results with per-result summaries/snippets. Its backend engine is selected by `CHAT_WEB_SEARCH_ENGINE`: `exa` (default), `brave` (requires `BRAVE_SEARCH_API_KEY`), or `searxng` (requires `SEARXNG_BASE_URL`; the instance must allow `format=json`).
 - `fetch_url` fetches a URL with browser-like navigation headers and returns plaintext page content (HTML converted to text server-side).
 - `codex_exec` delegates coding, shell, repository inspection, and other complex software tasks to a persistent remote Codex CLI workspace over SSH. The server runs `codex exec --dangerously-bypass-approvals-and-sandbox --skip-git-repo-check <non-interactive wrapped prompt>` on the configured devbox inside `CHAT_CODEX_REMOTE_WORKDIR`, with SSH stdin closed.
 - `shell_exec` runs arbitrary non-interactive shell commands on the same configured devbox, starting in `CHAT_CODEX_REMOTE_WORKDIR`. It uses `bash -lc` when bash exists, otherwise `sh -lc`, closes SSH stdin, and does not run inside the Sybil server container.

docs/api/streaming-chat.md

@@ -182,7 +182,7 @@ Terminal tool-call event:
 - `xai` and `hermes-agent`: image attachments are sent as Chat Completions content parts; text attachments are inlined as text parts.
 - `openai`: Responses calls that can enter the server-managed tool loop use `store: true` so reasoning and function-call items can be passed between tool rounds.
 - `anthropic`: streamed via event stream; emits `delta` from `content_block_delta` with `text_delta`, and emits normalized `tool_call` SSE events when Anthropic `tool_use` blocks are executed. Image attachments are sent as base64 `image` blocks and text attachments are appended as `text` blocks.
-- `web_search` uses `CHAT_WEB_SEARCH_ENGINE` (`exa` default, or `searxng` with `SEARXNG_BASE_URL` set). SearXNG mode requires the instance to allow `format=json`. This only affects chat-mode tool calls, not search-mode endpoints.
+- `web_search` uses `CHAT_WEB_SEARCH_ENGINE`: `exa` (default), `brave` (requires `BRAVE_SEARCH_API_KEY`), or `searxng` (requires `SEARXNG_BASE_URL`; the instance must allow `format=json`). This only affects chat-mode tool calls, not search-mode endpoints.
 - `codex_exec` is available only when `CHAT_CODEX_TOOL_ENABLED=true`. It SSHes to `CHAT_CODEX_REMOTE_HOST`, creates/uses `CHAT_CODEX_REMOTE_WORKDIR`, and runs `codex exec --dangerously-bypass-approvals-and-sandbox --skip-git-repo-check <non-interactive wrapped prompt>` there with SSH stdin closed. Prefer `CHAT_CODEX_SSH_KEY_PATH` with a read-only mounted private key; `CHAT_CODEX_SSH_PRIVATE_KEY_B64` is also supported.
 - `shell_exec` is available only when `CHAT_SHELL_TOOL_ENABLED=true`. It uses the same devbox SSH configuration, starts in `CHAT_CODEX_REMOTE_WORKDIR`, and runs non-interactive shell commands there with SSH stdin closed, not inside the Sybil server container.
 - `CHAT_MAX_TOOL_ROUNDS` controls how many model/tool result cycles may occur before the backend returns a tool-call limit message; default is 100.

server/README.md

@@ -48,7 +48,8 @@ If `ADMIN_TOKEN` is not set, the server runs in open mode (dev).
 - `HERMES_AGENT_API_KEY` (enables the Hermes Agent provider; set to Hermes `API_SERVER_KEY`, or any non-empty value if that local server does not require auth)
 - `HERMES_AGENT_MODEL` (optional fallback/override model id; defaults client-side to `hermes-agent`)
 - `EXA_API_KEY`
-- `CHAT_WEB_SEARCH_ENGINE` (`exa` by default, or `searxng` for chat tool calls only)
+- `BRAVE_SEARCH_API_KEY` (required when `CHAT_WEB_SEARCH_ENGINE=brave`)
+- `CHAT_WEB_SEARCH_ENGINE` (`exa` by default; `brave` and `searxng` are also supported for chat tool calls only)
 - `SEARXNG_BASE_URL` (required when `CHAT_WEB_SEARCH_ENGINE=searxng`; instance must allow `format=json`)
 - `CHAT_MAX_TOOL_ROUNDS` (`100` by default; maximum model/tool result cycles per chat completion)
 - `CHAT_CODEX_TOOL_ENABLED` (`false` by default; enables the `codex_exec` chat tool for managed-tool providers)

server/src/env.ts

@@ -24,7 +24,7 @@ const ChatWebSearchEngineSchema = z.preprocess(
     const trimmed = value.trim();
     return trimmed ? trimmed.toLowerCase() : undefined;
   },
-  z.enum(["exa", "searxng"]).default("exa")
+  z.enum(["exa", "searxng", "brave"]).default("exa")
 );
 
 const BooleanFlagSchema = z.preprocess((value) => {
@@ -71,6 +71,7 @@ const EnvSchema = z.object({
   HERMES_AGENT_API_KEY: OptionalTrimmedStringSchema,
   HERMES_AGENT_MODEL: OptionalTrimmedStringSchema,
   EXA_API_KEY: z.string().optional(),
+  BRAVE_SEARCH_API_KEY: OptionalTrimmedStringSchema,
 
   // Chat-mode web_search tool configuration. Search mode remains Exa-only for now.
   CHAT_WEB_SEARCH_ENGINE: ChatWebSearchEngineSchema,
@@ -100,6 +101,14 @@ const EnvSchema = z.object({
     });
   }
 
+  if (value.CHAT_WEB_SEARCH_ENGINE === "brave" && !value.BRAVE_SEARCH_API_KEY) {
+    ctx.addIssue({
+      code: "custom",
+      path: ["BRAVE_SEARCH_API_KEY"],
+      message: "BRAVE_SEARCH_API_KEY is required when CHAT_WEB_SEARCH_ENGINE=brave",
+    });
+  }
+
   if ((value.CHAT_CODEX_TOOL_ENABLED || value.CHAT_SHELL_TOOL_ENABLED) && !value.CHAT_CODEX_REMOTE_HOST) {
     ctx.addIssue({
       code: "custom",

server/src/llm/chat-tools.ts

@@ -7,6 +7,7 @@ import { convert as htmlToText } from "html-to-text";
 import { z } from "zod";
 import { buildBrowserLikeNavigationHeaders } from "../browser-fetch-headers.js";
 import { env } from "../env.js";
+import { searchBrave } from "../search/brave.js";
 import { exaClient } from "../search/exa.js";
 import { searchSearxng } from "../search/searxng.js";
 import type { ChatMessage } from "./types.js";
@@ -507,11 +508,33 @@ async function runSearxngWebSearchTool(args: WebSearchArgs): Promise<ToolRunOutc
   };
 }
 
+async function runBraveWebSearchTool(args: WebSearchArgs): Promise<ToolRunOutcome> {
+  const response = await searchBrave(args.query, {
+    numResults: args.numResults ?? DEFAULT_WEB_RESULTS,
+    includeDomains: args.includeDomains,
+    excludeDomains: args.excludeDomains,
+  });
+
+  return {
+    ok: true,
+    searchEngine: "brave",
+    query: args.query,
+    requestId: response.requestId,
+    results: response.results.map((result, index) => ({
+      rank: index + 1,
+      ...result,
+    })),
+  };
+}
+
 async function runWebSearchTool(input: unknown): Promise<ToolRunOutcome> {
   const args = WebSearchArgsSchema.parse(input);
   if (env.CHAT_WEB_SEARCH_ENGINE === "searxng") {
     return runSearxngWebSearchTool(args);
   }
+  if (env.CHAT_WEB_SEARCH_ENGINE === "brave") {
+    return runBraveWebSearchTool(args);
+  }
   return runExaWebSearchTool(args);
 }
 

server/src/search/brave.ts

@@ -0,0 +1,168 @@
+import { buildBrowserLikeRequestHeaders } from "../browser-fetch-headers.js";
+import { env } from "../env.js";
+
+const BRAVE_WEB_SEARCH_URL = "https://api.search.brave.com/res/v1/web/search";
+const BRAVE_SEARCH_TIMEOUT_MS = 12_000;
+
+export type BraveSearchOptions = {
+  numResults: number;
+  includeDomains?: string[];
+  excludeDomains?: string[];
+};
+
+export type BraveSearchResult = {
+  title: string | null;
+  url: string | null;
+  publishedDate: string | null;
+  author: string | null;
+  summary: string | null;
+  text: string | null;
+  highlights: string[];
+};
+
+export type BraveSearchResponse = {
+  query: string;
+  requestId: string | null;
+  results: BraveSearchResult[];
+};
+
+function clipText(input: string, maxCharacters: number) {
+  return input.length <= maxCharacters ? input : `${input.slice(0, maxCharacters)}...`;
+}
+
+function compactWhitespace(input: string) {
+  return input.replace(/\r/g, "").replace(/[ \t]+\n/g, "\n").replace(/\n{3,}/g, "\n\n").replace(/\s+/g, " ").trim();
+}
+
+function requireBraveSearchApiKey() {
+  if (!env.BRAVE_SEARCH_API_KEY) {
+    throw new Error("BRAVE_SEARCH_API_KEY not set");
+  }
+  return env.BRAVE_SEARCH_API_KEY;
+}
+
+function normalizeDomain(input: string) {
+  const trimmed = input.trim().toLowerCase();
+  if (!trimmed) return null;
+
+  try {
+    const parsed = new URL(trimmed.includes("://") ? trimmed : `https://${trimmed}`);
+    return parsed.hostname.replace(/^www\./, "");
+  } catch {
+    return trimmed.split(/[/?#]/, 1)[0]?.replace(/^www\./, "") || null;
+  }
+}
+
+function normalizeDomains(input: string[] | undefined) {
+  return Array.from(new Set((input ?? []).map(normalizeDomain).filter((domain): domain is string => Boolean(domain))));
+}
+
+function hostnameMatchesDomain(urlRaw: string | null, domain: string) {
+  if (!urlRaw) return false;
+  try {
+    const hostname = new URL(urlRaw).hostname.toLowerCase().replace(/^www\./, "");
+    return hostname === domain || hostname.endsWith(`.${domain}`);
+  } catch {
+    return false;
+  }
+}
+
+function filterResultsByDomains(results: BraveSearchResult[], options: BraveSearchOptions) {
+  const includeDomains = normalizeDomains(options.includeDomains);
+  const excludeDomains = normalizeDomains(options.excludeDomains);
+  return results.filter((result) => {
+    if (includeDomains.length && !includeDomains.some((domain) => hostnameMatchesDomain(result.url, domain))) return false;
+    if (excludeDomains.some((domain) => hostnameMatchesDomain(result.url, domain))) return false;
+    return true;
+  });
+}
+
+function buildBraveQuery(query: string, options: BraveSearchOptions) {
+  const includeDomains = normalizeDomains(options.includeDomains);
+  const excludeDomains = normalizeDomains(options.excludeDomains);
+  const includeClause =
+    includeDomains.length === 0
+      ? ""
+      : includeDomains.length === 1
+        ? `site:${includeDomains[0]}`
+        : `(${includeDomains.map((domain) => `site:${domain}`).join(" OR ")})`;
+  const excludeClause = excludeDomains.map((domain) => `-site:${domain}`).join(" ");
+  return [query, includeClause, excludeClause].filter(Boolean).join(" ");
+}
+
+function buildSearchUrl(query: string, options: BraveSearchOptions) {
+  const url = new URL(BRAVE_WEB_SEARCH_URL);
+  url.searchParams.set("q", buildBraveQuery(query, options));
+  url.searchParams.set("count", String(options.numResults));
+  url.searchParams.set("safesearch", "moderate");
+  url.searchParams.set("result_filter", "web");
+  url.searchParams.set("text_decorations", "false");
+  url.searchParams.set("extra_snippets", "true");
+  return url;
+}
+
+function stringOrNull(value: unknown) {
+  if (typeof value !== "string") return null;
+  const normalized = compactWhitespace(value);
+  return normalized || null;
+}
+
+function stringArray(value: unknown) {
+  if (!Array.isArray(value)) return [];
+  return value.filter((item): item is string => typeof item === "string").map(compactWhitespace).filter(Boolean);
+}
+
+function mapWebResult(result: any): BraveSearchResult {
+  const description = stringOrNull(result?.description);
+  const extraSnippets = stringArray(result?.extra_snippets);
+  const snippets = [description, ...extraSnippets].filter((snippet): snippet is string => Boolean(snippet));
+  const combinedText = snippets.join("\n\n");
+
+  return {
+    title: stringOrNull(result?.title),
+    url: stringOrNull(result?.url),
+    publishedDate: stringOrNull(result?.page_age),
+    author: stringOrNull(result?.profile?.name) ?? stringOrNull(result?.article?.author),
+    summary: description ? clipText(description, 1_400) : null,
+    text: combinedText ? clipText(combinedText, 700) : null,
+    highlights: snippets.slice(0, 3).map((snippet) => clipText(snippet, 280)),
+  };
+}
+
+export async function searchBrave(query: string, options: BraveSearchOptions): Promise<BraveSearchResponse> {
+  const url = buildSearchUrl(query, options);
+  const controller = new AbortController();
+  const timeout = setTimeout(() => controller.abort(), BRAVE_SEARCH_TIMEOUT_MS);
+
+  let response: Response;
+  try {
+    response = await fetch(url, {
+      signal: controller.signal,
+      headers: {
+        ...buildBrowserLikeRequestHeaders("application/json"),
+        "X-Subscription-Token": requireBraveSearchApiKey(),
+      },
+    });
+  } finally {
+    clearTimeout(timeout);
+  }
+
+  if (!response.ok) {
+    await response.arrayBuffer();
+    throw new Error(`Brave Search API request failed with status ${response.status}.`);
+  }
+
+  const contentType = response.headers.get("content-type")?.toLowerCase() ?? "";
+  if (!contentType.includes("application/json")) {
+    await response.arrayBuffer();
+    throw new Error(`Brave Search API returned ${contentType || "unknown content type"}.`);
+  }
+
+  const data: any = await response.json();
+  const results = Array.isArray(data?.web?.results) ? data.web.results.map(mapWebResult) : [];
+  return {
+    query,
+    requestId: response.headers.get("x-request-id"),
+    results: filterResultsByDomains(results, options).slice(0, options.numResults),
+  };
+}

server/tests/brave-search.test.ts

@@ -0,0 +1,111 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { env } from "../src/env.js";
+import { searchBrave } from "../src/search/brave.js";
+
+test("searchBrave authenticates, builds filters, and normalizes web results", async () => {
+  const originalFetch = globalThis.fetch;
+  const originalApiKey = env.BRAVE_SEARCH_API_KEY;
+  const fetchCalls: Array<{ input: RequestInfo | URL; init?: RequestInit }> = [];
+  env.BRAVE_SEARCH_API_KEY = "test-brave-key";
+  globalThis.fetch = (async (input: RequestInfo | URL, init?: RequestInit) => {
+    fetchCalls.push({ input, init });
+    return new Response(
+      JSON.stringify({
+        web: {
+          results: [
+            {
+              title: " Brave result ",
+              url: "https://docs.example.com/article",
+              description: "Main\n snippet",
+              extra_snippets: ["Extra snippet one", "Extra snippet two"],
+              page_age: "2026-07-18T12:00:00Z",
+              profile: { name: "Example Docs" },
+            },
+            {
+              title: "Excluded result",
+              url: "https://blocked.example.com/article",
+              description: "Should be filtered",
+            },
+          ],
+        },
+      }),
+      {
+        status: 200,
+        headers: {
+          "content-type": "application/json; charset=utf-8",
+          "x-request-id": "brave-request-1",
+        },
+      }
+    );
+  }) as typeof fetch;
+
+  try {
+    const response = await searchBrave("latest docs", {
+      numResults: 5,
+      includeDomains: ["https://example.com/path"],
+      excludeDomains: ["blocked.example.com"],
+    });
+
+    assert.equal(fetchCalls.length, 1);
+    const requestUrl = new URL(String(fetchCalls[0]?.input));
+    assert.equal(requestUrl.origin + requestUrl.pathname, "https://api.search.brave.com/res/v1/web/search");
+    assert.equal(requestUrl.searchParams.get("q"), "latest docs site:example.com -site:blocked.example.com");
+    assert.equal(requestUrl.searchParams.get("count"), "5");
+    assert.equal(requestUrl.searchParams.get("safesearch"), "moderate");
+    assert.equal(requestUrl.searchParams.get("result_filter"), "web");
+    assert.equal(requestUrl.searchParams.get("text_decorations"), "false");
+    assert.equal(requestUrl.searchParams.get("extra_snippets"), "true");
+    assert.equal((fetchCalls[0]?.init?.headers as Record<string, string>)["X-Subscription-Token"], "test-brave-key");
+
+    assert.deepEqual(response, {
+      query: "latest docs",
+      requestId: "brave-request-1",
+      results: [
+        {
+          title: "Brave result",
+          url: "https://docs.example.com/article",
+          publishedDate: "2026-07-18T12:00:00Z",
+          author: "Example Docs",
+          summary: "Main snippet",
+          text: "Main snippet\n\nExtra snippet one\n\nExtra snippet two",
+          highlights: ["Main snippet", "Extra snippet one", "Extra snippet two"],
+        },
+      ],
+    });
+  } finally {
+    globalThis.fetch = originalFetch;
+    env.BRAVE_SEARCH_API_KEY = originalApiKey;
+  }
+});
+
+test("searchBrave rejects requests without an API key", async () => {
+  const originalApiKey = env.BRAVE_SEARCH_API_KEY;
+  env.BRAVE_SEARCH_API_KEY = undefined;
+  try {
+    await assert.rejects(() => searchBrave("test", { numResults: 1 }), /BRAVE_SEARCH_API_KEY not set/);
+  } finally {
+    env.BRAVE_SEARCH_API_KEY = originalApiKey;
+  }
+});
+
+test("searchBrave reports non-JSON responses", async () => {
+  const originalFetch = globalThis.fetch;
+  const originalApiKey = env.BRAVE_SEARCH_API_KEY;
+  env.BRAVE_SEARCH_API_KEY = "test-brave-key";
+  globalThis.fetch = (async () =>
+    new Response("upstream error", {
+      status: 200,
+      headers: { "content-type": "text/plain" },
+    })) as typeof fetch;
+
+  try {
+    await assert.rejects(
+      () => searchBrave("test", { numResults: 1 }),
+      /Brave Search API returned text\/plain/
+    );
+  } finally {
+    globalThis.fetch = originalFetch;
+    env.BRAVE_SEARCH_API_KEY = originalApiKey;
+  }
+});