haden-browser は、ローカルの Model Context Protocol サーバーとして公開される、高速でAIファーストなWebブラウザです。AIに対して、毎ターンスクリーンショットや生のページソースを送る代わりに、現在の目標にとって最も小さく有用なページ表現を提供します。
主な結果: Haden はコアブラウジングセッションで 7,822 トークン を使用しました。これは Playwright MCP より 32.7% 少なく、Chrome DevTools MCP フルモードより 32.5% 少ない 数値です。セマンティックなアクション参照と画像altテキストのカバレッジを返すテスト済みブラウザMCPの中で、Haden は最も低いトークンフットプリントを記録しました。
5回実行の中央値 | Haden | Playwright MCP | Chrome Slim† | Chrome Full |
コアコンテキストトークン | 7,822 | 11,627 | 4,638 | 11,596 |
ツールスキーマトークン | 727 | 3,999 | 221 | 4,974 |
記事ワークフロートークン | 2,732 | 4,640 | 2,497 | 4,388 |
最初の有用な記事 | 1,044 ms | 2,714 ms | 3,005 ms | 3,133 ms |
記事オリジン転送量 | 16.7 KB / 1 リクエスト | 95.0 KB / 10 | 95.0 KB / 10 | 95.0 KB / 10 |
セマンティックアクション参照 | 15 | 172 | 0 | 143 |
画像altカバレッジ | 8/8 | 8/8 | 0/8 | 8/8 |
† Chrome Slim は絶対的なトークン最小値ですが、これは低レベルなJavaScript制御のベースラインです。モデルがページスクリプトを作成する必要があり、テストしたパスではセマンティックなアクション参照や画像altテキストが返されませんでした。そのため、透明性のために表示していますが、セマンティックブラウザと同等とは見なしていません。
コアコンテキストには、完全なツールスキーマの読み込みと、記事の読み取り、フォーム送信、計算スタイルの検査のためのシリアライズされたMCPツール呼び出しと結果が含まれます。カウントは o200k_base トークナイザーを使用しています。画像ピクセル、ユーザー/システムプロンプト、モデルの推論や散文は除外されているため、実際の課金使用量はMCPホストとモデルによって異なります。
完全なベンチマークレポート、実行ごとの生データ、再現手順 を参照してください。
Related MCP server: Charlotte
目標ベースのビュー — リサーチにはコンパクトなセマンティックテキスト、構造にはサニタイズされたDOM、ビジュアル作業には境界のある計算スタイルを使用します。
画像は遅延読み込み — 画像はaltテキストまたは [image img1] として表現されます。ピクセルデータは、AIが明示的に haden_image を呼び出した場合にのみ返されます。
低ラウンドトリップ制御 — すべてのインタラクションが新しいスナップショットを返すため、ほとんどのクリック/タイプフローはステップごとに1回のツール呼び出しで済みます。
安定したアクション参照 — 表示されているコントロールは e1、e2 などになり、モデルにCSSセレクタを考案させるよりも安価で信頼性が高くなります。
デフォルトで高速 — 通常のブラウジング中は、画像、メディア、フォントのリクエストがブロックされます。CSSはビジュアルビューで利用可能です。
より安全なローカル実行 — HTTP以外のスキーム、資格情報を含むURL、プライベートネットワークターゲットは、ユーザーが明示的にオプトインしない限りブロックされます。
flowchart LR
AI[AI / MCP host] -->|stdio tools| MCP[haden-browser]
MCP --> PW[Playwright Chromium]
PW --> PAGE[Web page]
PAGE -->|semantic text / DOM / computed CSS| MCP
MCP -.->|only haden_image imgN| PIXELS[Image bytes]
PIXELS -.-> AIビュー | 最適な用途 | 返されるデータ |
| 検索、読み取り、フォームフロー | 見出し、表示テキスト、 |
| HTML構造と属性 | サニタイズされたHTML。スクリプトと埋め込みコンテンツは削除され、 |
| レイアウトとCSS推論 | ボックスと境界のある計算CSSプロパティを持つ、表示されている意味のある要素 |
text がデフォルトであり、タスクが本当に構造やプレゼンテーションの詳細を必要としない限り、これを優先する必要があります。
ツール | 目的 |
| HTTP(S) URLを開き、最初のスナップショットを返します |
| 現在のページを読み取ります。オプションでCSSセレクタ内に限定します |
| クリック、入力、選択、キー押下、スクロール、履歴移動、リロード、待機を行い、更新されたスナップショットを返します |
| 最新のスナップショットから1つの |
| Chromiumを起動せずにアクティブなページを報告します |
テキスト出力の例:
# Example Domain
URL: https://example.com/
View: text
Interactive elements: 1
Images: 1 (use haden_image with an img ref only when visual inspection is needed)
# Example Domain
This domain is for use in illustrative examples.
[e1] link "More information" -> https://iana.org/domains/example
[image img1: "Example diagram"]参照は最新のスナップショットに限定されます。ページが大幅に変更された後は、古い e または img 参照を再利用する前に再度読み取ってください。
Node.js 20 以降
Playwright を通じてインストールされた Chromium
git clone https://github.com/Haden-Min/haden-browser.git
cd haden-browser
npm ci
npm run setup-browser
npm run build次に、MCPホストを構成して、ビルドされた stdio サーバーを起動します。実際の構成では絶対パスを使用してください:
{
"mcpServers": {
"haden-browser": {
"command": "node",
"args": ["/absolute/path/to/haden-browser/dist/index.js"]
}
}
}開発中は、ホストは npx tsx /absolute/path/to/haden-browser/src/index.ts を起動できます。
パッケージがnpmに公開された後、意図された構成は次のとおりです:
{
"mcpServers": {
"haden-browser": {
"command": "npx",
"args": ["-y", "haden-browser"]
}
}
}そのマシンで最初のブラウザ呼び出しの前に、npx playwright install chromium を一度実行してください。
環境変数 | デフォルト | 意味 |
|
| 表示ウィンドウなしでChromiumを実行します |
|
| 通常のブラウジング中に画像、メディア、フォントをブロックします |
|
| localhost とプライベートネットワークの宛先を許可します |
|
| ナビゲーションと画像フェッチのタイムアウト |
|
| クリック、入力、ロケーターのタイムアウト |
|
| デフォルトのスナップショット文字数制限 |
|
|
|
ブール変数は true/false、1/0、yes/no、on/off を受け入れます。
SSRFリスクを減らすため、プライベートホストはデフォルトでブロックされています。localhost 上のアプリケーションを閲覧するには、そのMCPプロセスのみオプトインしてください:
{
"mcpServers": {
"haden-browser-local": {
"command": "node",
"args": ["/absolute/path/to/haden-browser/dist/index.js"],
"env": { "HADEN_ALLOW_PRIVATE_HOSTS": "true" }
}
}
}npm install
npm run setup-browser
npm run check
npm run buildテストスイートは、ネットワークポリシー、テキスト整形、実際のChromium抽出、参照ベースのインタラクション、遅延画像取得、インメモリMCPクライアント/サーバー接続をカバーしています。
stdio MCP接続ごとに1つのアクティブなブラウザコンテキストが維持されます。
画像参照は現在、表示されているHTML <img> 要素をカバーしており、CSS背景画像、キャンバス、ビデオフレーム、iframeコンテンツはカバーしていません。
ビジュアルビューは計算されたプロパティを報告します。すべてのスタイルシートルールをダンプするわけではありません。
ダウンロード、ファイルアップロード、ブラウザ拡張機能、永続プロファイル、CAPTCHA解決はMVPの範囲外です。
プライベートホストフィルタリングはSSRF露出を減らしますが、敵対的なマルチテナント環境でのOS/コンテナレベルのネットワーク分離の代わりにはなりません。
開発ガイダンスについては CONTRIBUTING.md を、脆弱性の報告については SECURITY.md を参照してください。
MIT
Return the actual pixels for one img ref from the latest snapshot. Use only after alt text/placeholders are insufficient for the goal.
| Name | Required | Description | Default |
|---|---|---|---|
| ref | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, covering safety. The description adds context about the data source ('latest snapshot') and output nature ('actual pixels'), but doesn't detail return format or potential edge cases, which is acceptable given annotation coverage.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two concise sentences, front-loaded with the primary action and followed by a usage condition. Every word is purposeful, with no filler or repetition.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's simplicity (one param, no nested objects) and rich annotations (readOnly, openWorld, destructive), the description sufficiently covers what the tool does and when to use it. The absence of an output schema reduces the need to document return values.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
With one parameter (ref) and schema description coverage of 0%, the description does not explicitly explain the parameter format. However, the schema pattern (^img\d+$) and the phrase 'one img ref' provide some meaning. The description adds minimal semantic value beyond what the schema already implies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's function with a specific verb and resource: 'Return the actual pixels for one img ref from the latest snapshot.' This distinguishes it from sibling tools like haden_read or haden_open by focusing on image pixel retrieval.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
It provides explicit guidance on when to use the tool: 'Use only after alt text/placeholders are insufficient for the goal.' This implies alternatives (alt text/placeholders) and sets a clear condition, though it does not name specific sibling tools or list when-not-to-use scenarios.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Perform one browser action and immediately return the updated snapshot, avoiding an extra read call. click/fill/select need a current e ref; press can target a ref or the page.
| Name | Required | Description | Default |
|---|---|---|---|
| key | No | ||
| ref | No | ||
| mode | No | text | |
| value | No | ||
| action | Yes | ||
| amount | No | ||
| waitMs | No | ||
| maxChars | No | ||
| direction | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Describes the immediate return of the updated snapshot, adding value beyond the destructiveHint annotation. Does not contradict annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences, no fluff, well-structured and easy to parse.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Explains core behavior and return, but lacks detail on parameter usage and edge cases, which is somewhat expected given the 9 parameters and 3 enums.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Only partially explains parameters (action, ref), leaving many (key, value, amount, waitMs, maxChars) undocumented. Schema enums help but description does not compensate sufficiently.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Clearly states it performs a browser action and returns an updated snapshot, distinguishing it from read-only siblings like read and status.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Provides guidance on when to use (to avoid extra read calls) and which actions require a current ref, but does not explicitly contrast with alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Open an HTTP(S) URL and return an AI-optimized snapshot. text is fastest; dom returns sanitized HTML; visual adds computed layout/CSS.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | ||
| mode | No | text | |
| maxChars | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and destructiveHint, so the safety profile is clear. The description adds valuable behavioral details: returning an AI-optimized snapshot and specifying sanitized HTML for dom mode. It does not contradict annotations and offers meaningful context beyond them.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single sentence that front-loads the core action and then efficiently outlines mode differences. Every clause adds value; there is no fluff or redundancy. It is concise and well-structured.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a tool with 3 parameters, no output schema, and moderate complexity, the description covers purpose and mode meanings but omits maxChars explanation and does not clarify what 'snapshot' encompasses beyond the modes. It is adequate but leaves room for improvement, especially since schema coverage is zero.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema descriptions cover 0% of parameters, so the description must compensate. It effectively explains the mode parameter (text/dom/visual semantics), but fails to describe maxChars, leaving its purpose and constraints solely to the schema. Url is self-evident from its format but still lacks narrative. Given the low coverage, this is insufficient.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states the primary action (open an HTTP(S) URL) and the result (AI-optimized snapshot), making the purpose clear. It doesn't explicitly compare with sibling tools, but the resource and verb are specific enough to differentiate from likely 'read' or 'interact' functions.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Provides guidance on choosing output modes (text, dom, visual) with performance/reliability trade-offs, but lacks explicit direction on when to use this tool versus sibling tools like haden_read or haden_interact. The description implies usage for fetching web pages but does not state alternatives or exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Read the current page again, optionally limited to a CSS selector. Returns stable e refs for actions and img refs for optional image retrieval.
| Name | Required | Description | Default |
|---|---|---|---|
| mode | No | text | |
| maxChars | No | ||
| selector | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, so the description adds value by disclosing that refs are stable and that image retrieval is optional. It does not contradict annotations, and the additional behavioral context (stable refs) goes beyond the schema.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single concise sentence followed by a clarifying clause. It front-loads the core purpose and adds only high-value return info. No fluff, every word contributes.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With no output schema and 3 parameters lacking schema descriptions, the description is incomplete. It covers the selector's purpose but ignores mode and maxChars, which are essential for understanding output types and limits. The refs info helps but does not bridge the gap.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 0%, so the description must compensate. It explains 'selector' via 'optionally limited to a CSS selector', but gives no meaning for 'mode' (text/dom/visual) or 'maxChars'. This is a significant gap for effective tool invocation, as agents cannot infer the purpose of these parameters.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool reads the current page, optionally limited by a CSS selector, and mentions it returns stable refs for actions and images. This specific verb+resource+scope distinguishes it from siblings like haden_interact or haden_open.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies when to use it ('Read the current page again') and mentions optional selector, which suggests targeted reading. However, it does not explicitly state when NOT to use it or compare with alternatives like haden_image for visual capture, though the context is reasonably clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Report whether the browser is running and which page is active.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description aligns with the annotations (readOnlyHint=true, destructiveHint=false) and adds a small behavioral detail: it reports the active page, not just a running flag. However, it does not disclose what happens if the browser is not running, what 'active page' means in practice, or whether the tool returns a simple boolean, a URL, or both. With annotations already signaling safety, the description adds only modest context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, front-loaded sentence with no filler. Every word earns its place: it names the action, the target resource, and the exact two pieces of information reported.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a zero-parameter read-only status tool with no output schema, the description is sufficiently complete. It clearly states what the tool reports, and no additional input or prerequisite detail is needed. The absence of an output schema is compensated by specifying that the tool reports both browser-running state and active page.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The tool has zero parameters and the schema contains no properties, so the description does not need to explain parameter meaning. The baseline for a parameterless tool is 4, and the description correctly focuses on behavior rather than inputs.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb ('Report') and a clear resource ('whether the browser is running and which page is active'), making the tool's purpose immediately obvious. It is also clearly differentiated from sibling tools like haden_open, haden_read, haden_interact, and haden_image, which describe actions rather than state inspection.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no explicit guidance about when to use this tool versus alternatives, nor any when-not-to-use conditions. The context is implied by the name and siblings, but the description does not state that this should be used before acting on the browser or how it relates to the other browser tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
v0.1.0haden_imagehaden_interacthaden_openhaden_readhaden_statusScored across 5 tools
Each tool has a unique, non-overlapping purpose: open, read, interact, image, and status. No ambiguity between them.
All tools follow the consistent 'haden_' prefix with clear action verbs (open, read, interact, image, status). The pattern is uniform.
Five tools provide a well-scoped set for browser automation—covering navigation, reading, interaction, visual capture, and state checking—without excess or deficiency.
The set covers core browser operations, but lacks explicit navigation controls (e.g., back, forward, refresh) and waiting mechanisms. These can be worked around via interact/open, but are minor gaps.
Web data extraction and browser workflows for AI assistants.
Reliable web access for AI agents: smart HTTP, rotating proxies, and full-browser rendering.
Web pages as clean Markdown and JSON for AI agents, in fewer tokens, with an Evidence Record.
Agent-native search engine with live web research optimized for AI agents.
