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elasticsearch7-mcp

by agrica

Elasticsearch 7.x MCP Server

MCP クライアント(Claude Desktop、Cursor など)から Elasticsearch クラスターに直接接続するための MCP サーバーです。

[!IMPORTANT] このフォークは Elasticsearch 7.x のみを対象としています。@elastic/elasticsearch の 7.17 クライアントを固定しており、 その Product Check は 7.14 より前のサーバーも許可します。Elasticsearch 8.x クラスターの場合は、 このフォークの元になったアップストリームプロジェクト @awesome-ai/elasticsearch-mcp を使用してください — 8.x クライアントは 7.x サーバーと通信できず、その逆も同じです。

このサーバーは、Model Context Protocol を使用してエージェントを Elasticsearch データに接続します。自然言語での会話を通じて Elasticsearch インデックスを操作できます。

機能概要

ツールは3つのセットに分かれています。常に公開されるのは最初のセットだけです。残りの2つは環境変数によるオプトインなので、本番環境では削除機能を提供せずに診断機能だけを提供できます。ゲート制御は登録時に行われます。無効なツールは tools/list に一切表示されないため、モデルはそれを呼び出せず、エージェントのコンテキストも消費しません。

常に利用可能 — データの読み取りと書き込み

クラスター

  • elasticsearch_health: クラスターのヘルス状態(オプションでインデックスレベルまで)

  • cluster_info: クラスター名、Elasticsearch のバージョンとビルドのフレーバー

インデックス操作

  • list_indices: インデックスの一覧を Elasticsearch ワイルドカード(log-*)でフィルタリングして表示

  • create_index: オプションの設定とマッピングを指定してインデックスを作成

  • reindex: インデックスをコピーする(クエリでのフィルタリングやスクリプトでの変換も可能)

  • get_aliases: どのエイリアスがどのインデックスを指しているかを確認する

マッピング

  • get_mappings: インデックスのフィールドを、型付きのドットパスとして表示し、続けて生のマッピングを表示

  • create_mapping: インデックスのマッピングを作成または更新

検索とデータ

  • search: クエリ DSL で検索を実行。クエリ自身が highlight を持っていない限り、すべてのテキストフィールド(ネストされたものも含む)にハイライトを注入

  • count: ドキュメントを転送せずに、マッチするドキュメント数を返す

  • get_document: ID を指定して1件のドキュメントを取得

  • bulk: 多数のドキュメントを一度にインデックス登録

テンプレート

  • create_index_template: コンポーザブルインデックステンプレートを作成または更新

  • get_index_template: インデックステンプレートを読み取る

タスク

  • get_task: reindex が返すような長時間実行タスクの進捗状況を確認する

ES_ADMIN_TOOLS=true — 診断(読み取り専用)

これらは読み取り専用なので、本番環境で有効にしても安全です。このセットのポイントはまさにそこにあります。エージェントは、誰かがクラスターにログインしなくても、インデックスが不健全な理由を説明できます。

  • explain_allocation: シャードが未割り当ての理由と、各アロケーターの判断結果を表示

  • list_shards: シャードレベルの状態を確認。STARTED ではないコピーを先頭に表示

  • list_nodes: ノードごとのヒープ、CPU、ロード、ディスク圧力を確認

  • get_index_stats: インデックスごとのカウンター — サイズ、セグメント、インデクシング、検索、マージ

  • get_index_settings: インデックスの設定(refresh_interval、レプリカ、読み取り専用ブロック)を取得

  • get_cluster_settings: 実行時に上書きされたクラスター設定を確認

  • list_tasks: クラスターが現在実行中のタスクを確認

ES_ALLOW_DESTRUCTIVE=true — 元に戻せない操作

ステージング環境を想定しており、デフォルトではオフなので、本番環境からは一切到達できません。

  • delete_index: インデックスとそのデータを削除

  • delete_document: ID を指定して1件のドキュメントを削除

  • delete_by_query: クエリにマッチするすべてのドキュメントを削除 — 非同期で、タスク ID を返し、削除はバックグラウンドで続行

  • delete_index_template: インデックステンプレートを削除

フラグが有効でも、これらはワイルドカード、カンマ区切りのリスト、*、_all を拒否します。対象は一度に1つの名前付きインデックスだけです。logs-* を単一のインデックスと誤解したモデルは、クラスターを空にする代わりに拒否を受け取ります。

仕組み

  1. MCP クライアントがリクエストを分析し、必要な Elasticsearch 操作を判断します。

  2. MCP サーバーがその操作を実行します(インデックス一覧の取得、マッピングの取得、検索の実行)。

  3. MCP クライアントが結果を処理し、ユーザーフレンドリーな形で表示します。

Related MCP server: Elasticsearch 7.x MCP Server

はじめに

前提条件

  • Elasticsearch 7.x インスタンス(7.8 で検証済み。7.17 クライアントは 6.8 から 7.x をサポート)

  • Elasticsearch の認証情報 — API キー、またはユーザー名とパスワード

  • MCP クライアント: Claude Code、Claude Desktop、Codex、Cursor、その他 stdio で MCP を話せるもの

GitHub Packages への認証(一度だけ)

[!IMPORTANT] このパッケージは GitHub Packages に公開されており、npmjs.com ではありません。GitHub Packages は 公開パッケージでもトークンが必要です。トークンを追加するまで、以下のすべてのインストールは 401 で失敗します。 ユーザーレベルの ~/.npmrc に追加してください:

@agrica:registry=https://npm.pkg.github.com
//npm.pkg.github.com/:_authToken=YOUR_GITHUB_TOKEN

YOUR_GITHUB_TOKEN は read:packages スコープを持つ personal access token です。

プロジェクトファイルではなく、自分の ~/.npmrc に置いてください — リポジトリにコミットされたトークンは漏洩したトークンです。また、一部のパッケージマネージャーはそこから読み取ることを完全に拒否します。

クライアントに接続する

以降のすべての例では ES_HOST と ES_API_KEY を設定しています。ベーシック認証を使う場合は ES_USERNAME / ES_PASSWORD に置き換え、診断ツールを使うには ES_ADMIN_TOOLS=true を追加し、複数のインスタンスを宣言する場合は ES_INSTANCE_LABEL を設定してください — 設定オプション を参照してください。

claude mcp add elasticsearch7 \
  --env ES_HOST=https://your-cluster:9200 \
  --env ES_API_KEY=your-api-key \
  --env ES_ADMIN_TOOLS=true \
  -- npx -y @agrica/elasticsearch7-mcp

セッション内で /mcp を実行すると、サーバーとそのツールが一覧表示されます。

間違いやすい点が2つあります:

  • -- の後ろはすべてサーバーを実行するコマンドです。これがないと Claude Code は -y を自分自身のフラグとして解析しようとします。

  • サーバー名を --env の直後に置かないでください。CLI はそれを別の KEY=value ペアとして読み取り、拒否します。上の例ではサーバー名が先頭にあるため、うまく動作します。

サーバーはローカルスコープで追加されるため、現在のプロジェクトでのみ読み込まれます。どこでも使えるようにするには --scope user を、チームと共有するために .mcp.json に書き込むには --scope project を追加してください — コミットされた .mcp.json には API キーが含まれることになるので、認証情報は user スコープを推奨します。

claude_desktop_config.json を編集します。設定 > 開発者 > 設定を編集 で開くか、Windows の %APPDATA%\Claude\ または macOS の ~\Library\Application\Support\Claude\ にあります:

{
  "mcpServers": {
    "elasticsearch7": {
      "command": "npx",
      "args": ["-y", "@agrica/elasticsearch7-mcp"],
      "env": {
        "ES_HOST": "https://your-cluster:9200",
        "ES_API_KEY": "your-api-key",
        "ES_ADMIN_TOOLS": "true"
      }
    }
  }
}

その後、Claude Desktop を再起動します。このファイルは起動時にしか読み込まれません。

codex mcp add elasticsearch7 \
  --env ES_HOST=https://your-cluster:9200 \
  --env ES_API_KEY=your-api-key \
  -- npx -y @agrica/elasticsearch7-mcp

または、~/.codex/config.toml に手動で書き込むこともできます。Codex ではテーブル名がアンダースコア付きの mcp_servers となり、環境変数はインラインではなく独立したサブテーブルに入ることに注意してください。

[mcp_servers.elasticsearch7]
command = "npx"
args = ["-y", "@agrica/elasticsearch7-mcp"]

[mcp_servers.elasticsearch7.env]
ES_HOST = "https://your-cluster:9200"
ES_API_KEY = "your-api-key"
ES_ADMIN_TOOLS = "true"

Codex 内で /mcp と入力すると、サーバーが読み込まれていることを確認できます。

このサーバーは通常の stdio MCP サーバーなので、MCP クライアント一覧 にあるどのクライアントでも動作します。必要なものは3つです: コマンド npx、引数 -y @agrica/elasticsearch7-mcp、そして環境変数の ES_* 群です。ポートで待ち受けることはなく、stdout には MCP プロトコル以外を書きません — 診断情報は stderr に送られます。

設定オプション

Elasticsearch MCP Server は、Elasticsearch に接続するための設定オプションをサポートしています。

[!NOTE] API キーか、ユーザー名とパスワードの両方のどちらかを指定する必要があります。

環境変数

説明

必須

ES_HOST

Elasticsearch インスタンスの URL。単一の URL またはカンマ区切りの複数 URL に対応(HOST も可)

はい

ES_API_KEY

認証用の Elasticsearch API キー(API_KEY も可)

いいえ

ES_USERNAME

ベーシック認証用の Elasticsearch ユーザー名(USERNAME も可)

いいえ

ES_PASSWORD

ベーシック認証用の Elasticsearch パスワード(PASSWORD も可)

いいえ

ES_CA_CERT

Elasticsearch の SSL/TLS 用カスタム CA 証明書のパス(CA_CERT も可)

いいえ

ES_REQUEST_TIMEOUT

リクエストごとのタイムアウト(ミリ秒)。デフォルト 30000。多くのインデックスを集計する際にタイムアウトするなら値を引き上げてください。

いいえ

ES_MAX_RETRIES

リクエストごとの再試行回数。デフォルト 3。0 で無効化されます。

いいえ

ES_MAX_RESULT_BYTES

ツール結果の容量の上限。デフォルト 32768。これを超えると詳細が省略され、結果にその旨が表示されます。

いいえ

ES_INSTANCE_LABEL

このデプロイの自由記述名(例: production)。サーバーのタイトルとして表示されるため、並んでいる複数のインスタンスを区別できます。

いいえ

ES_ADMIN_TOOLS

true で読み取り専用の診断ツールも公開します。デフォルトはオフ。

いいえ

ES_ALLOW_DESTRUCTIVE

true で元に戻せないツールも公開します。デフォルトはオフ。

いいえ

[!WARNING] ES_ADMIN_TOOLS と ES_ALLOW_DESTRUCTIVE には、上記の接続変数とは異なり、接頭辞のないレガシーエイリアスがありません。これは意図的なものです。裸の ADMIN_TOOLS や ALLOW_DESTRUCTIVE が環境変数にあると、deletion がどの環境からも到達できるかどうかを決めるものを、誤って設定してしまいがちです。

どちらも true または 1 を受け付けます。それ以外は、環境変数が未設定も含み、オフとして扱まれます。

結果サイズ

ツールの結果は 32 KB(ES_MAX_RESULT_BYTES)に上限が設定されています。特にログ集約クラスターでは重要です。上限がない場合、1年間の日次インデックスを対象にした list_shards を1回呼び出すと、1つの応答で 385 KB — 約 96,000 トークン — が返り、ほとんどのセッションが保持しきれない容量になります。

結果が切り詰められると、その旨が表示され、どれだけ切り捨てられたか、どのような小さな質問をすれば良いかが示されます。3つのツールはこれに合わせて応答を整形します。

  • list_indices と list_shards は読み取り可能なサマリーを返し、それと同じ行がテキストとして verbose に含まれます。

  • search は1回の呼び出しで size を 100 に制限し、ページングするための from ををします。

  • get_mappings は最初にフィールドを次に生のマッピングを return するため、フィールドが多数あっても質問に答えられます。

list_indices、list_shards、get_index_settings、get_mappings の4つは、読み取り可能な応答に加えて、型付けられた構造化出力でも答えを返します。クライアントはテキストを解析せずに表の行を読むことができます。これは、読みやすく応答が残した余りから作られるため、部分的な一覧が数値として確認できます。returned と total が表示されます。

pnpm run measure をビルドした出力に対して実行すると、現在の数値を自分の設定で確認できます。

複数のインスタンスのラベル付け

ほとんどの構成では、このサーバーを複数回宣言します — クラスターごとに1エントリです。エントリはそれ以外は同一なので、クライアントには同じ名前のサーバーが並び、区別できません。 ES_INSTANCE_LABEL はサーバーの表示タイトルになります。エントリがどの環境に向いているかを示すのに最適です。

{
  "mcpServers": {
    "es7-prod": {
      "command": "npx",
      "args": ["-y", "@agrica/elasticsearch7-mcp"],
      "env": {
        "ES_HOST": "https://es-prod:9200",
        "ES_API_KEY": "prod-key",
        "ES_INSTANCE_LABEL": "production",
        "ES_ADMIN_TOOLS": "true"
      }
    },
    "es7-staging": {
      "command": "npx",
      "args": ["-y", "@agrica/elasticsearch7-mcp"],
      "env": {
        "ES_HOST": "https://es-staging:9200",
        "ES_API_KEY": "staging-key",
        "ES_INSTANCE_LABEL": "staging",
        "ES_ADMIN_TOOLS": "true",
        "ES_ALLOW_DESTRUCTIVE": "true"
      }
    }
  }
}

That pair is the intended shape: diagnostics on both, but only removes is staging. Production keeps the tools that explain an unhealthy index, and never exposes a mechanism by which data could be removed — the model cannot call what never got registered.

The label is also printed to stderr at startup, which is what to look at when a client reports a connection but you can't tell which cluster answered.

複数の URL 設定

高可用性とロードバランシングのために、複数の Elasticsearch ノードを設定できます:

{
  "mcpServers": {
    "elasticsearch7-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@agrica/elasticsearch7-mcp"
      ],
      "env": {
        "ES_HOST": "https://es-node1:9200,https://es-node2:9200,https://es-node3:9200",
        "ES_API_KEY": "your-api-key"
      }
    }
  }
}

設定されたノード間で、クライアントが自動的にフェイルオーバーとロードバランスを処理してくれます。

Docker で実行する

各リリースは、マルチアーカイブ イメージ (linux/amd64, linux/arm64) を GitHub Container Registry に公開しています:

docker pull ghcr.io/agrica/elasticsearch7-mcp:latest

サーバーは stdio で通信するので、コンテナにはインタラクティブな標準入力が必要で、公開ポートは必要ありません。MCP クライアントの中では:

{
  "mcpServers": {
    "elasticsearch7-mcp": {
      "command": "docker",
      "args": [
        "run", "--rm", "-i",
        "-e", "ES_HOST",
        "-e", "ES_API_KEY",
        "ghcr.io/agrica/elasticsearch7-mcp:latest"
      ],
      "env": {
        "ES_HOST": "your-elasticsearch-host",
        "ES_API_KEY": "your-api-key"
      }
    }
  }
}

[!NOTE] npm パッケージと同様、このイメージも GitHub Packages にあります。リポジトリは公開されていますが、 取得するには read:packages スコープが付いたトークンが必要です。

イメージには公開ポートもボリュームも不要です。stdio で通信するので、標準入出力は MCP クライアントのものになります。

クエリ例

[!TIP] ここでは、MCP クライアントで試すことのできる自然言語クエリをいくつか紹介します。

クラスタ管理

  • "私の Elasticsearch クラスタのヘルス状態はどうなっていますか?"

  • "頂点にあるクラスタには、有効なノードがいくつありますか?"

インデックス操作

  • "私の Elasticsearch クラスタには、どのインデックスがありますか?"

  • "‘users’ という新しいインデックスを、シャード3つ・レプリカ1つの構成で作成して。"

  • "‘old_index’ から ‘new_index’ にデータを再インデックスして。"

マッピング管理

  • "‘products’ インデックスのフィールドマッピングを表示して。"

  • "‘products’ インデックスに、‘tags’ という keyword タイプのフィールドを追加して。"

検索 & データ操作

  • "先月の 500 ドルを超える注文をすべて検索して。"

  • "どの製品がもっとも星5つのレビューを取得されましたか?"

  • "この顧客レコードを、’customers’ インデックスに一括インポートして。"

テンプレート管理

  • "‘logs-*’ というパターンのログ用インデックステンプレートを作成して。"

  • "持っているインデックステンプレートをすべて表示して。"

診断 (ES_ADMIN_TOOLS=true が必要)

  • "‘logs-2026’ インデックスが黄色です。なぜシャードが未割当てなのですか?"

  • "ディスクのウォーターマークに近いノードはありますか?"

  • "自分のインデックスの中でどれが最も大きく、そのうちどのくらいが削除済みドキュメントですか?"

  • "このクラスタで誰かがシャードの割当を無効にしたログがありますか?"

  • "再インデックスがまだ実行中ですか?"

破壊的操作 (ES_ALLOW_DESTRUCTIVE=true が必要)

  • "‘smoke-test-source’ インデックスを削除して。"

  • "‘logs-archive’ から 2024 年より前のドキュメントを全部削除して。"

トラブルシューティング

症状

原因

インストール or npx で npmerror code E401 が出る

ユーザーレベルの ~/.pipab に GitHub Packages のトークンがありません。GitHub Packages への認証 参照してください。

起動時に Server error: ... invalid url が出る

ES_HOST が未設定か不正です。後で最初のクエリが失敗しないように、起動時に意図的に検証しています。

クライアントは接続するが、診断ツールまたは削除ツールが無い

そのセットは制御されています。 ES_ADMIN_TOOLS=true または ES_ALLOW_DESTRUCTIVE=true を設定して、クライアントを再起動してください。

Refusing to act on the pattern "logs-*"

仕様です。破壊的ツールはパターンではなく、具体的なインデックス名1つのみを受け入まります。フラグが有効でも同じです。

product check を含む接続エラー

クラスタが8.x か、到達不能です。このビルドは 7.x のみを対象にしています。

バグを見つけたか、足りないツールありますか? GitHub リポジトリで issue を開いてください。コードを扱う場合は、CONTRIBUTING.md から始めてください。

Available Tools

17 tools
analyzeAnalyze textA
Read-onlyIdempotent

Show the terms a text is broken into, which is what a query must produce to match. Pass field with index to use the analyzer that index really applies to that field; that is the form that explains a search returning nothing.

ParametersJSON Schema
NameRequiredDescriptionDefault
textYesText to analyze
fieldNoUse this field's analyzer, taken from the index mapping.
indexNoIndex whose analyzers to use. Required with field.
analyzerNoNamed analyzer to test instead, e.g. standard, french.

TDQS

A4.2/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, and non-destructive, so no safety disclosure is missing. The description adds semantic behavior: output is the token terms a query must match, and using field/index routes to the real per-field analyzer. It neither contradicts annotations nor reveals side-effect caveats beyond that, so a mid score is appropriate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two compact sentences, the first states the core function and the second adds the key usage nuance. No filler or repetition of schema details.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only diagnostic with one required parameter, the description plus schema covers what the tool does, how to choose a real-field analyzer, and why it matters for debugging searches. No output schema exists, but the description directly states the observable result ('terms a text is broken into'). It doesn't discuss response shape details, but they are unnecessary for basic invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so parameter basics are already documented. The description adds the important combination rule (field must be paired with index) and explains that the analyzer is taken from the index mapping, which is value beyond individual property docs. It earns an above-baseline score.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a concrete operation — showing the tokenized terms produced from text — and ties it to query matching, so an agent understands what analyze returns. It also distinguishes the field/index form from a standalone analyzer test. This goes well beyond the vague title.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives explicit guidance on the field-index combination as the way to use the actual analyzer applied by the index, and states this is the form that explains an empty search result. It doesn't explicitly enumerate alternatives or when to use the analyzer parameter, but the context is sufficient for a user to choose sensibly.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

bulkBulk index documentsA

Index up to 1000 documents in one call. The index is refreshed by default, so they are searchable immediately; per-document failures are reported without failing the call.

ParametersJSON Schema
NameRequiredDescriptionDefault
indexYesTarget index
idFieldNoField whose value becomes the document _id. Omit to let Elasticsearch generate ids.
refreshNoDefaults to true, making documents searchable at once. Set false when loading many batches: forcing a refresh per batch is the expensive part.
documentsYesDocuments to index, at most 1000. Send more in successive batches.

TDQS

A4.3/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds useful behavioral detail beyond the annotations: the index is refreshed by default so documents are immediately searchable, and per-document failures are reported without failing the whole call. This meaningfully informs the agent about side effects and error handling.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences deliver the key information without redundancy: the action, the batch limit, the refresh behavior, and the failure handling. It is front-loaded with the most important operational constraint.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given a complete input schema, a moderate number of parameters, and annotations covering the read/write profile, the description covers the important behavioral nuances—immediate searchability and partial failures. No critical information for invoking the tool correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the parameters are already well documented in the schema. The description reinforces the 1000-document limit and the default refresh behavior, but adds little semantic value beyond what the schema already states.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific action ('Index'), a concrete resource ('documents'), and a clear constraint ('up to 1000 documents in one call'). This clearly separates it from siblings like create_index, create_mapping, and reindex, which target different operations.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description establishes when bulk indexing is appropriate: when you have up to 1000 documents to index in a single call. It also explains the default refresh behavior, which helps an agent decide when to override it. It does not explicitly name alternatives, but the batching context is clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

cluster_infoCluster version and identityA
Read-onlyIdempotent

Cluster name, Elasticsearch version and build flavour. The version decides which query DSL features exist.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

TDQS

A3.7/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds useful context about the returned fields and the role of the version, but it does not disclose additional behavioral traits like response structure, authentication needs, or whether values are cached.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two short sentences: the first front-loads the exact fields returned, and the second gives a brief reason the version matters. There is no filler or redundant restating of the title.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a parameterless, read-only metadata tool without an output schema, the description adequately covers what the agent gets (name, version, flavour) and why version is useful. It could be slightly richer by noting the response is a flat JSON object, but that is a minor omission for such a simple tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so there is no parameter burden on the description. The schema is effectively empty and the baseline for 0 params is 4.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly identifies the resource (cluster identity: name, version, build flavour), but it uses a noun phrase rather than a specific verb like 'returns' or 'lists'. It is distinguishable from siblings by its focus on cluster metadata, yet it never explicitly differentiates itself from elasticsearch_health or other info tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The statement 'The version decides which query DSL features exist' implies when this tool is relevant: checking version-dependent DSL feature support. However, it does not explicitly say when to use it versus alternatives, nor does it mention any exclusions or prerequisites.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

countCount documentsA
Read-onlyIdempotent

Count the documents matching a query, without transferring any. Cheaper than search when only the number matters.

ParametersJSON Schema
NameRequiredDescriptionDefault
indexYesIndex to count in
queryNoQuery DSL. Omit to count every document.

TDQS

A4.5/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds useful behavioral context beyond annotations: no documents are transferred and this operation is cheaper than search. This is meaningful information without contradicting the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences with no redundant words. The core action is front-loaded and the benefit/alternative is stated in the second sentence.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read-only counting tool, the description, schema, and annotations together cover the required parameters, the optional query behavior, the safety profile, and the use case. The return value (a count) is obvious from the tool's purpose, so no output schema is needed.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents index and query, including that omitting query counts every document. The description does not add further parameter-level meaning but does not need to.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb-resource pairing ('Count the documents matching a query') and immediately differentiates from the sibling search tool by noting it transfers no documents. An agent can tell exactly what operation this performs and how it differs from search.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It explicitly states the condition for choosing count over search: 'when only the number matters,' and notes it is 'Cheaper than search.' The phrase 'without transferring any' also implies that search should be used when actual documents are needed.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

create_indexCreate an indexA

Create a new index. Fails if it already exists — use create_mapping to add fields to an existing one.

ParametersJSON Schema
NameRequiredDescriptionDefault
indexYesIndex name
mappingsNoField mappings, e.g. { properties: { title: { type: 'text' } } }
settingsNoIndex settings, e.g. number_of_shards, number_of_replicas

TDQS

A4.4/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds a valuable behavioral detail beyond the annotations: the operation fails rather than overwriting when the index already exists. This complements the annotations, which already indicate a non-read-only, non-idempotent write operation. It does not elaborate on all side effects, but the conflict behavior is the key operational trait.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences with no filler. It leads with the core action, then immediately states the failure condition and the correct alternative. Every sentence serves a distinct purpose and the structure makes it easy to scan.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description, together with the fully documented schema and annotations, provides enough context for correct invocation: required parameter, optional mapping/settings parameters, and the failure mode. It does not mention the create_index_template sibling, but that is not essential for invoking this specific tool correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

All three parameters are already documented in the input schema, including examples for mappings and settings, so schema coverage is 100%. The description does not add additional parameter-level meaning, but it does not need to; the schema carries that burden effectively.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific action and resource: 'Create a new index.' It also differentiates itself from the closest sibling, create_mapping, by explicitly saying to use that tool for adding fields to an existing index. The purpose is immediately clear and not a tautology.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives explicit when-to-use guidance: use this tool for creating a new index. It also gives an explicit when-not-to-use and alternative: 'Fails if it already exists — use create_mapping to add fields to an existing one.' This leaves little ambiguity about which tool to select.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

create_index_templateCreate or update an index templateA
Idempotent

Create or update a composable index template (Elasticsearch 7.8+). It applies only to indices created after it, never to existing ones.

ParametersJSON Schema
NameRequiredDescriptionDefault
nameYesTemplate name
versionNoVersion number, for your own tracking
priorityNoPrecedence when several templates match; higher wins
templateYesWhat to apply: { settings, mappings, aliases }
indexPatternsYesIndex wildcards the template applies to, e.g. ['logs-*']

TDQS

A4.2/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate a mutating, idempotent, non-destructive operation. The description adds important behavior beyond the annotations: the Elasticsearch 7.8+ requirement and the non-retroactive nature of the template. No contradiction exists between description and annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single sentence communicates the action, resource, version constraint, and the most important behavioral caveat with no filler. The key scoping limitation is front-loaded and easy to parse.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a write tool with 5 parameters, a nested template object, and no output schema, the description covers the decisive behavioral constraint and version compatibility while relying on the fully documented schema for parameter details. It does not mention the response format, but that is a minor gap for a create/update tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all five parameters already have inline documentation. The description does not add substantial parameter-level meaning beyond the schema, making the baseline 3 appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Create or update') and a specific resource ('composable index template'), which clearly distinguishes it from sibling tools like create_index or create_mapping. The version qualifier and 'applies only to indices created after it' add further precision about what the tool does.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear context: this tool is for defining templates that affect future indices only, and it explicitly states it never affects existing indices. It does not name alternative tools for existing-index changes, but the exclusion is clear enough for an agent to reason about when to use it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

create_mappingCreate or update a mappingA
Idempotent

Add or update fields on an index, creating the index if it does not exist. Elasticsearch cannot change the type of an existing field.

ParametersJSON Schema
NameRequiredDescriptionDefault
indexYesIndex name
mappingsYesMapping to apply, e.g. { properties: { tags: { type: 'keyword' } } }

TDQS

A4.2/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate idempotent, non-read-only, and non-destructive behavior. The description adds valuable constraints beyond annotations, especially the critical limitation that 'Elasticsearch cannot change the type of an existing field', which helps agents anticipate failures.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tightly written sentences. The first conveys the core action and index-creation behavior, and the second adds the most important caveat. There is no filler or repetition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a two-parameter tool with a clear schema, the description covers the main behavioral caveat and typical usage. It does not describe the response shape, but given no output schema and the simplicity of the operation, the description is largely sufficient.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with both parameters documented well; the mappings parameter even includes an example shape. The description itself adds no additional parameter-level detail, so the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Add or update') and resource ('fields on an index') and clarifies that it can create the index if needed. This clearly differentiates it from sibling tools like get_mappings or create_index.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear context: use this tool to mutate mappings, including when the index does not yet exist. It does not explicitly name alternatives or state when not to use it, but the operational scope is clear enough to guide selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

elasticsearch_healthCluster healthB
Read-onlyIdempotent

Cluster health: status, node counts and shard counts.

ParametersJSON Schema
NameRequiredDescriptionDefault
includeIndicesNoAdd per-index health detail

TDQS

B3.4/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the description does not need to re-establish safety. The description does add useful information about the return content (status, node counts, shard counts), which is helpful because there is no output schema. It does not add deeper behavioral context such as whether includeIndices changes response structure substantially, but that is partially covered by the parameter description.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is one short, front-loaded sentence: 'Cluster health: status, node counts and shard counts.' Every word earns its place, and there is no redundancy or filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read-only tool with zero required parameters and a well-documented optional parameter, the description covers the essential return content. The annotations cover the safety profile, and the schema covers the parameter. It is only missing explicit guidance for distinguishing it from cluster_info, which is already penalized under usage guidelines.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and the only parameter, includeIndices, already has a meaningful description: 'Add per-index health detail'. The tool description adds no additional parameter semantics beyond the schema, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names the exact resource ('cluster health') and the specific output areas (status, node counts, shard counts), which makes the tool's purpose reasonably clear. It lacks an explicit verb like 'get', but the noun-phrase style with tool name 'elasticsearch_health' is sufficient. It is distinguishable from index-focused siblings like list_indices and get_mappings, though cluster_info could overlap without more detail.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no guidance on when to use this tool versus alternatives. With sibling cluster_info likely covering similar cluster-level information, the absence of a routing note is a real gap. Any usage guidance is only implied by the name and the word 'health'.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

field_capsField capabilitiesA
Read-onlyIdempotent

Which fields exist across an index pattern and whether each is searchable and aggregatable. Takes a wildcard, unlike get_mappings, and is the only way to see a field mapped as two different types across indices — which makes an aggregation over it silently partial rather than failing.

ParametersJSON Schema
NameRequiredDescriptionDefault
indexYesIndex, alias or wildcard, e.g. logs-app-*
fieldsNoField name or wildcard to ask about, e.g. log.* — comma-separated for several. Defaults to every field.

TDQS

A4.5/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: wildcard acceptance, cross-index type conflict visibility, and the non-obvious consequence that aggregations over such fields become silently partial rather than failing. This is exactly the kind of behavioral warning an agent needs.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tight sentences: the first delivers the core purpose, the second adds the distinguishing behavior and its operational warning. Every clause earns its place, and the most decision-relevant information is front-loaded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple two-parameter, read-only tool, the description covers the essential facts: what it returns, how it differs from its sibling, and a critical edge-case consequence. The schema and annotations carry the remaining details, so nothing an agent needs to invoke it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already describes both parameters clearly, including wildcard behavior and defaults, giving 100% schema description coverage. The description does not substantially add parameter-level meaning beyond that, so the baseline of 3 is appropriate; it reinforces the wildcard theme but introduces no new parameter detail.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a precise statement of what the tool returns: fields across an index pattern plus whether each is searchable and aggregatable. It further distinguishes itself from get_mappings by calling out wildcard support and the special case of fields mapped as two different types, making the tool's identity unmistakable.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly names get_mappings as the alternative and gives a concrete differentiator ('Takes a wildcard, unlike get_mappings'). It also establishes a strong when-to-use condition: it is the only way to detect a field mapped as two different types. It does not spell out the reverse case ('use get_mappings when...'), but the intended routing is clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

get_aliasesList aliasesA
Read-onlyIdempotent

List which aliases point to which indices. A name you query may be an alias, which changes what get_mappings returns.

ParametersJSON Schema
NameRequiredDescriptionDefault
indexNoIndex or wildcard. Omit for the whole cluster.

TDQS

A4.2/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive behavior. The description adds behavioral context by warning that aliases affect get_mappings results, which is useful beyond the annotations. No contradiction exists.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, no filler. The core purpose is front-loaded, and the second sentence adds valuable contextual information without unnecessary length.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read-only tool with one optional parameter and no output schema, the description provides sufficient guidance. It could mention what the response contains, but the annotations and sibling context cover most operational concerns.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the optional 'index' parameter is already documented. The description doesn't add parameter-level detail beyond what the schema states, which matches the baseline for high schema coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb and resource: 'List which aliases point to which indices.' It clearly communicates the tool's purpose and implicitly distinguishes it from sibling tools like list_indices and get_mappings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives concrete context for when this tool matters: when a queried name may be an alias and alters what get_mappings returns. It does not explicitly name alternatives or exclusion criteria, but the usage context is clear enough for an agent.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

get_documentGet a document by idA
Read-onlyIdempotent

Fetch one document by its _id. Reports that it is absent rather than failing.

ParametersJSON Schema
NameRequiredDescriptionDefault
idYesDocument _id
indexYesIndex holding the document

TDQS

A4.2/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds a meaningful behavioral trait beyond those annotations: it reports that a document is absent rather than failing. This tells the agent how missing documents are handled, which is useful for interpreting results.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two short sentences with no wasted words. The core action is front-loaded, and the second sentence adds a useful behavioral note. It is concise without sacrificing important information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple get-by-id tool with two fully documented parameters and strong annotations, the description is largely complete. It does not specify the exact return shape or concrete absent representation, such as null or an empty result, but 'Fetch one document' and 'Reports that it is absent rather than failing' cover the essential behavior an agent needs.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both parameters are already documented in the schema. The description adds little beyond the schema, aside from referring to '_id' in a way that maps to the id parameter. Baseline 3 is appropriate because the schema carries the parameter semantics.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: 'Fetch one document by its _id.' It clearly distinguishes this from sibling tools like search or get_index_template by narrowing scope to a single document identified by _id. The additional detail about reporting absence rather than failing reinforces its unique purpose.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives a clear usage context: use this tool when you need exactly one document by its _id. It does not explicitly name alternatives or exclusions, but the stated single-document-by-id behavior is enough to imply the appropriate scenario and separate it from broader search or listing tools.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

get_index_templateGet index templatesA
Read-onlyIdempotent

Get composable index templates. Omit name to list all.

ParametersJSON Schema
NameRequiredDescriptionDefault
nameNoTemplate name. Omit to list every template.

TDQS

A3.8/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering safety semantics. The description adds the list-all behavior when name is omitted, but does not disclose output shape, errors, or other runtime behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two short, purposeful sentences with no filler. The main operation is front-loaded, and the optional-name behavior is expressed efficiently.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple, optional-parameter, read-only tool with strong annotations, the description is nearly complete. It could mention the return format or that it returns template definitions, but an agent has enough information to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and the schema already explains that 'name' is optional and that omitting it lists every template. The description restates this without adding new semantic details, so the baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the operation ('Get'), the resource ('composable index templates'), and the key behavior ('Omit name to list all'). This makes the tool's purpose immediately obvious and distinguishes it from create_index_template and other read-only sibling tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear guidance on omitting the name to list all templates, but it does not explicitly discuss when to choose this tool over alternatives such as get_mappings or create_index_template. Usage context is mostly implied rather than stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

get_mappingsGet index mappingsA
Read-onlyIdempotent

List the fields of one index as dotted paths with their types, nested fields included, then the raw mapping. Give a concrete index name: an alias or a wildcard returns nothing.

ParametersJSON Schema
NameRequiredDescriptionDefault
indexYesIndex name

Output Schema

ParametersJSON Schema
NameRequiredDescription
foundYes
indexYes
totalYes
fieldsYes
omittedYes
returnedYes

TDQS

A4.5/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds useful behavior beyond annotations by specifying the output format (dotted paths with types, then raw mapping) and the alias/wildcard caveat, which is exactly the kind of context an agent needs.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two compact sentences front-load the tool's output behavior and then give the critical input constraint. Every sentence earns its place, with no filler or repetition of the schema.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the simple one-parameter schema, the presence of an output schema, and annotations covering safety, the description is complete. It explains what the response contains, when a call will succeed, and when it will return nothing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema fully documents the single 'index' parameter with 100% coverage, so the baseline is 3. The description adds real semantic value by requiring a concrete index and warning that aliases and wildcards yield no results, which is not inferable from the schema alone.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific action ('List the fields of one index as dotted paths with their types') and a concrete resource ('one index'), and it distinguishes the tool by noting nested fields are included and the raw mapping follows. This separates get_mappings from siblings like get_index_template or field_caps without requiring the agent to inspect schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear operational guidance: pass a concrete index name, and avoid aliases or wildcards because they return nothing. It does not explicitly name alternative sibling tools, but the precondition and failure mode are actionable enough for an agent to decide when to invoke this tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

get_taskGet task progressA
Read-onlyIdempotent

Check an asynchronous task, such as the one reindex returns: progress, completion and failure.

ParametersJSON Schema
NameRequiredDescriptionDefault
taskIdYesTask id as returned by reindex, e.g. node-1:428

TDQS

A3.9/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the tool read-only, idempotent, and non-destructive, so the safety profile is covered. The description adds that the task reports progress, completion, and failure, but it does not explain response format or polling behavior; this is modest added value beyond the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single front-loaded sentence that names the action, the resource, the source of the task id, and the relevant outcomes. Every phrase earns its place with no redundant wording.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter polling tool with rich annotations, the description is complete: it says what to check, where the task id comes from, and what aspects are reported. No output schema exists, but the description names the key result dimensions well enough for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already provides 100% coverage for taskId, including its meaning and an example. The description only reinforces that the task id comes from reindex, adding no new parameter semantics beyond what the schema already supplies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool checks an asynchronous task and identifies the specific scenario (tasks returned by reindex). It names the observable outcomes (progress, completion, failure), making the purpose unambiguous, though it does not explicitly differentiate from siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides a clear usage context: use this after an asynchronous operation such as reindex that returns a task id. It does not state when-not-to-use or name alternatives, but the context is concrete enough for an agent to select it appropriately.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

list_indicesList indicesA
Read-onlyIdempotent

List indices, one compact line each: name, health, status, document count and size in bytes. Large results are trimmed and say so.

ParametersJSON Schema
NameRequiredDescriptionDefault
patternNoElasticsearch wildcard, e.g. `logs-*`. Not a regex. Defaults to `*`.
verboseNoAlso repeat the rows as JSON text, for a client that does not read structured output.

Output Schema

ParametersJSON Schema
NameRequiredDescription
totalYes
indicesYes
omittedYes
patternYes
returnedYes

TDQS

A4.3/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description goes beyond the read-only and idempotent annotations by disclosing the compact per-line format and the important trimming behavior for large results. This prevents an agent from assuming the output is always complete. Safety is already covered by annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences front-load the purpose and output shape, then add the trimming caveat. Every phrase earns its place and there is no boilerplate.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With only two optional parameters, a full output schema, and annotations covering safety and idempotence, the description supplies the key behavioral caveat (trimming) and output fields. An agent has everything needed to invoke list_indices correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already documents both parameters at 100% coverage, including the wildcard-vs-regex distinction for pattern and the purpose of verbose. The description adds no parameter-level detail, so the baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific operation ('List indices') and defines the exact output fields (name, health, status, document count, size in bytes), making it immediately distinguishable from sibling tools like get_mappings or field_caps. It clearly identifies the resource and the compact representation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The output description clearly implies its use case: obtaining a compact overview of indices with health and size information. It does not explicitly name sibling alternatives or state exclusions, so it falls just short of full routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

reindexReindex into another indexA

Copy documents between indices. Asynchronous: returns a task id at once and the copy is still running on return — poll it with GET _tasks/.

ParametersJSON Schema
NameRequiredDescriptionDefault
queryNoQuery DSL selecting which documents to copy. Omit to copy all.
scriptNoTransform each document while copying
destIndexYesDestination index, created if absent
sourceIndexYesSource index

TDQS

A4/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description goes beyond the annotations by disclosing the crucial asynchronous behavior: it returns a task id immediately while the copy continues, and it tells the caller how to poll progress. Annotations already cover read/write/destructive aspects, and the description adds meaningful operational context without contradicting them.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tight sentences: the first states the action clearly, and the second adds the key behavioral caveat and how to follow up. No filler or repetition of schema content.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with nested parameters and no output schema, the description explains the main return signal (task id) and the continuation mechanism. It is sufficient for an agent to select and invoke the tool correctly, though it does not detail edge cases or result formats beyond the task id.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and the schema already documents sourceIndex, destIndex, query, and script with meaningful descriptions. The tool description adds no parameter-specific detail, but the schema carries that burden fully, so the baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb and resource pair: 'Copy documents between indices.' This clearly distinguishes reindex from read-only search, single-document get, and indexing/bulk operations, and the title reinforces the same intent.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description clearly implies when to use this tool: when documents must be copied between indices. However, it does not explicitly explain when not to use it or mention alternatives such as bulk for direct writes or search for read-only queries. The async polling hint gives practical usage context, but no explicit routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Tool Schema Changelog

Recent tool additions, removals, and schema changes observed during successful MCP inspections.

  1. 17 tool updatesv0.4.1
    • First observedanalyze
    • First observedbulk
    • First observedcluster_info
    • First observedcount
    • First observedcreate_index
    • First observedcreate_index_template
    • First observedcreate_mapping
    • First observedelasticsearch_health
    • First observedfield_caps
    • First observedget_aliases
    • First observedget_document
    • First observedget_index_template
    • First observedget_mappings
    • First observedget_task
    • First observedlist_indices
    • First observedreindex
    • First observedsearch

TDQS

A3.7/5.0

Scored across 17 tools

Disambiguation5/5

Each tool targets a distinct operation or resource: field inspection is split cleanly between get_mappings and field_caps, with explicit notes about wildcard vs concrete index behavior. create_index, create_mapping, bulk, and reindex are also clearly differentiated, so an agent should not confuse them.

Naming Consistency3/5

Most tools use get_, list_, or create_ prefixes, but bare nouns and verbs like bulk, count, reindex, field_caps, cluster_info, and elasticsearch_health break the verb_noun pattern. Naming is readable and consistently snake_case, but the conventions are mixed.

Tool Count3/5

17 tools is on the heavy side for a single server and makes agent tool selection slightly harder. Each tool does map to a real Elasticsearch operation, so the count is not excessive, but it is borderline.

Completeness2/5

The surface covers health, mappings, search, indexing, and templates, but lacks delete/update operations for documents and indices, and has no deletion for aliases or templates. This creates significant dead ends for common lifecycle workflows.

Maintenance

ActivitySlowing
ResponsivenessNo issues

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