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imagen-mcp

インテリジェントなマルチプロバイダー画像生成のためのModel Context Protocol (MCP) サーバーです。

CI Python 3.10+ License: MIT

クイックスタート

1. APIキーを取得する (少なくとも1つ):

プロバイダー

キーの取得先

環境変数

OpenAI

platform.openai.com/api-keys

OPENAI_API_KEY

Google Gemini

aistudio.google.com/apikey

GEMINI_API_KEY

両方のキーを持つことで最良の結果が得られます。サーバーはプロンプトごとに最適なプロバイダーを自動的に選択します。キーが1つしかない場合でも、もう一方のプロバイダーに適したプロンプトは機能しますが、フォールバック通知が表示されます。

2. MCPクライアントに追加する (いずれかを選択):

claude mcp add -s user imagen \
  -e OPENAI_API_KEY=sk-... \
  -e GEMINI_API_KEY=AI... \
  -- npx -y imagen-mcp

登録されていることを確認します:

claude mcp list

参照: Claude Code MCP docs

設定ファイルを編集します:

  • macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

  • Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "imagen": {
      "command": "npx",
      "args": ["-y", "imagen-mcp"],
      "env": {
        "OPENAI_API_KEY": "sk-...",
        "GEMINI_API_KEY": "AI..."
      }
    }
  }
}

編集後、Claude Desktopを再起動します (Cmd+Qで終了し、再度開く)。

参照: Claude Desktop MCP docs

オプションA — CLIコマンド:

codex mcp add imagen -- npx -y imagen-mcp

オプションB — ~/.codex/config.toml を直接編集:

[mcp_servers.imagen]
command = "npx"
args = ["-y", "imagen-mcp"]

[mcp_servers.imagen.env]
OPENAI_API_KEY = "sk-..."
GEMINI_API_KEY = "AI..."

参照: Codex MCP docs

~/.gemini/settings.json を編集:

{
  "mcpServers": {
    "imagen": {
      "command": "npx",
      "args": ["-y", "imagen-mcp"],
      "env": {
        "OPENAI_API_KEY": "sk-...",
        "GEMINI_API_KEY": "AI..."
      }
    }
  }
}

参照: Gemini CLI MCP docs

設定

コマンド

npx

引数

["-y", "imagen-mcp"]

環境変数

OPENAI_API_KEY および/または GEMINI_API_KEY

3. 画像を生成する — AIアシスタントに依頼します:

"スタジオ照明でプロフェッショナルなヘッドショットを生成して"

以上です。サーバーが自動的に最適なプロバイダーを選択します。


Related MCP server: ImageGen MCP Server

機能

  • 自動プロバイダー選択 — プロンプトを分析して最適なプロバイダーを選択

  • マルチプロバイダーサポート — OpenAI GPT-Image-1 および Google Gemini

  • 参照画像 — キャラクターやスタイルの整合性のために最大14枚の画像を使用可能 (Gemini)

  • リアルタイムデータ — 最新情報のためのGoogle検索グラウンディング (Gemini)

  • 会話形式での調整 — コンテキストを使用して画像を反復的に調整

  • 高解像度 — 最大4K出力 (Gemini)

  • フォールバック通知 — 設定されていないプロバイダーの方が適している場合に明確な警告を表示

自動選択の仕組み

サーバーはプロンプトを分析し、最適なプロバイダーにルーティングします:

"Create a menu card for an Italian restaurant"  -> OpenAI (text rendering)
"Professional headshot with studio lighting"    -> Gemini (photorealism)
"Infographic about climate change"              -> OpenAI (diagram + text)
"Product shot of perfume on marble"             -> Gemini (product photography)

最適なプロバイダーが設定されていない場合は? サーバーは設定済みのプロバイダーにフォールバックし、以下のように通知します:

プロバイダーのフォールバック: このプロンプトにはGeminiの方が適していますが(フォトリアルなコンテンツ)、設定されていません。代わりにOpenAIを使用します。より良い結果を得るには GEMINI_API_KEY を設定してください。

provider パラメーターを使用して、いつでも自動選択を上書きできます:

generate_image(prompt="...", provider="openai")
generate_image(prompt="...", provider="gemini")

プロバイダー比較

機能

OpenAI GPT-Image-1

Gemini Nano Banana Pro

テキストレンダリング

優秀

良好

フォトリアリズム

良好

優秀

速度

約60秒

約15秒

最大解像度

1536x1024

4K

サイズ

3オプション

1K, 2K, 4K

アスペクト比

3

10

参照画像

なし

あり (最大14枚)

リアルタイムデータ

なし

あり (Google検索)

OpenAIの用途: テキストが多い画像、メニュー、インフォグラフィック、コミック、図表

Geminiの用途: ポートレート、商品写真、4K出力、参照画像

MCPツール

ツール

説明

generate_image

自動プロバイダー選択を備えたメインツール

conversational_image

対話と履歴を用いた複数ターンの調整

list_conversations

アクティブな会話とその履歴を一覧表示

list_providers

利用可能なプロバイダーと機能を表示

list_gemini_models

利用可能なGemini画像モデルを照会

出力場所

画像はデフォルトで ~/Downloads/images/{provider}/ (openai/ または gemini/ サブディレクトリ) に保存されます。

カスタマイズ方法:

# Save to a specific directory (auto-generated filename)
generate_image(prompt="...", output_path="~/Desktop/logos/")

# Save to a specific file
generate_image(prompt="...", output_path="~/Desktop/logos/my-logo.png")

OUTPUT_DIR を設定してベースディレクトリをグローバルに変更します。ログは {OUTPUT_DIR}/logs/ に保存されます。

Gemini固有の機能

# High resolution
generate_image(prompt="...", size="4K")

# Specific model
generate_image(prompt="...", gemini_model="gemini-2.0-flash-exp-image-generation")

# Reference images for style/character consistency (base64 encoded)
generate_image(prompt="...", reference_images=["base64..."])

# Real-time data via Google Search
generate_image(prompt="Current weather in NYC", enable_google_search=True)

利用可能なモデル

OpenAI

モデルID

説明

gpt-image-1

専用画像生成モデル (デフォルト)

gpt-5-image

画像生成機能付きGPT-5

gpt-5.1

最新の推論モデル (会話オーケストレーション)

Gemini

モデルID

説明

gemini-3-pro-image-preview

Nano Banana Pro - 最高品質 (デフォルト)

gemini-2.0-flash-exp-image-generation

高速実験モデル

imagen-3.0-generate-002

代替画像モデル

アーキテクチャ

flowchart TB
    subgraph Clients["MCP Clients"]
        CD[Claude Desktop]
        CC[Claude Code CLI]
        GC[Gemini CLI]
        CX[Codex CLI]
    end

    subgraph Server["imagen-mcp Server"]
        MCP[MCP Protocol Layer]

        subgraph Tools["MCP Tools"]
            GI[generate_image]
            CI[conversational_image]
            LP[list_providers]
            LM[list_gemini_models]
        end

        subgraph Core["Core Components"]
            PS[Provider Selector]
            PR[Provider Registry]
        end

        subgraph Providers["Image Providers"]
            OAI[OpenAI Provider<br/>GPT-Image-1]
            GEM[Gemini Provider<br/>Nano Banana Pro]
        end
    end

    subgraph APIs["External APIs"]
        OAPI[OpenAI API]
        GAPI[Google Gemini API]
    end

    subgraph Storage["Local Storage"]
        DL[~/Downloads/images/]
    end

    CD & CC & GC & CX --> MCP
    MCP --> Tools
    GI & CI --> PS
    PS --> PR
    PR --> OAI & GEM
    OAI --> OAPI
    GEM --> GAPI
    OAI & GEM --> DL

環境変数

変数

説明

必須

OPENAI_API_KEY

OpenAI APIキー

少なくとも1つのAPIキー

GEMINI_API_KEY

Google Gemini APIキー

が必要です

GOOGLE_API_KEY

GEMINI_API_KEY のエイリアス

OUTPUT_DIR

保存された画像のベースディレクトリ

いいえ (デフォルト: ~/Downloads/images/)

DEFAULT_PROVIDER

デフォルトのプロバイダーを強制

いいえ (デフォルト: auto)

DEFAULT_OPENAI_SIZE

デフォルトのOpenAI画像サイズ

いいえ (デフォルト: 1024x1024)

DEFAULT_GEMINI_SIZE

デフォルトのGemini画像サイズ

いいえ (デフォルト: 2K)

ENABLE_GOOGLE_SEARCH

Google検索グラウンディングを有効化

いいえ (デフォルト: false)

IMAGEN_MCP_LOG_DIR

ログディレクトリの上書き

いいえ

IMAGEN_MCP_LOG_LEVEL

ログレベル (DEBUG, INFOなど)

いいえ

IMAGEN_MCP_LOG_PROMPTS

プロンプト全体をログに記録

いいえ (デフォルト: false)

トラブルシューティング

「No providers available」 少なくとも1つのAPIキーが必要です。MCPクライアント設定で OPENAI_API_KEY または GEMINI_API_KEY を設定してください (上記のクイックスタートを参照)。

画像は生成されるが、ポートレートや商品の品質が良くない おそらく GEMINI_API_KEY が不足しています。サーバーがOpenAIにフォールバックし、警告を表示しました。よりフォトリアルな結果を得るためにGeminiキーを追加してください。

画像は生成されるが、テキストの見た目が悪い おそらく OPENAI_API_KEY が不足しています。より良いテキストレンダリングのためにOpenAIキーを追加してください。

「npx: command not found」 Node.jsをインストールしてください (npxが含まれています): nodejs.org

画像はどこに保存されますか? デフォルト: ~/Downloads/images/openai/ または ~/Downloads/images/gemini/。正確なパスについてはツールの出力を確認してください。変更するには OUTPUT_DIR を設定します。

どのプロバイダーがアクティブかを確認するには? list_providers ツールを使用するか、以下を実行してください:

python3 -c "from src.providers import get_provider_registry; print(get_provider_registry().list_providers())"

開発

# Clone and install
git clone https://github.com/michaeljabbour/imagen-mcp.git
cd imagen-mcp
pip install -r requirements.txt

# Run tests
pip install pytest pytest-asyncio
pytest tests/ -v

# Verify server loads
python3 -c "from src.server import mcp; print('Server loads')"

# Check Claude Desktop logs (macOS)
tail -f ~/Library/Logs/Claude/mcp-server-imagen.log

プロジェクト構造

imagen-mcp/
├── src/
│   ├── server.py              # MCP entry point
│   ├── config/
│   │   ├── constants.py       # Provider constants
│   │   └── settings.py        # Environment configuration
│   ├── providers/
│   │   ├── base.py            # Abstract provider interface
│   │   ├── openai_provider.py # OpenAI implementation
│   │   ├── gemini_provider.py # Gemini implementation
│   │   ├── selector.py        # Auto-selection logic
│   │   └── registry.py        # Provider factory
│   └── models/
│       └── input_models.py    # Pydantic input models
├── tests/
│   ├── test_selector.py       # Provider selection tests
│   ├── test_providers.py      # Provider unit tests
│   └── test_server.py         # Server integration tests
├── .github/
│   └── workflows/
│       └── ci.yml             # GitHub Actions CI
├── run.sh                     # Wrapper script for MCP clients
├── requirements.txt
├── CLAUDE.md
└── README.md

要件

mcp>=1.16.0
fastmcp>=2.12.5
pydantic>=2.12.3
httpx>=0.24.0
google-genai>=1.52.0
pillow>=10.4.0

ライセンス

MIT

ソース

Available Tools

8 tools
conversational_imageA

Generate images conversationally with iterative refinement.

USE THIS TOOL when:

  • User gives a vague/incomplete prompt that needs refinement

  • User wants iterative refinement across multiple messages

  • User explicitly asks for guidance or suggestions

Dialogue Modes:

  • "quick": 1-2 questions, fast path

  • "guided": 3-5 questions, balanced (DEFAULT)

  • "explorer": Deep exploration with 6+ questions

  • "skip": Direct generation, no dialogue

Provider Selection: Same auto-selection logic as generate_image. Provider is locked for the duration of a conversation (cannot switch mid-conversation).

Usage Pattern:

  1. Initial: "A cozy coffee shop" → System asks refinement questions

  2. User answers questions

  3. Image generated with refined prompt

  4. Refine: "Add more plants" (with same conversation_id)

  5. Continue refining as needed

Args: params: Conversational image parameters including prompt and dialogue options.

Returns: Either dialogue questions or generated image with metadata.

ParametersJSON Schema
NameRequiredDescriptionDefault
paramsYes

Output Schema

ParametersJSON Schema
NameRequiredDescription
resultYes

TDQS

A4.1/5.0
Behavior4/5

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

Annotations provide readOnlyHint=false (mutation) and destructiveHint=false. The description adds behavioral traits beyond annotations: provider locking across conversations (cannot switch mid-conversation), dialogue modes impact on interaction depth, and the usage pattern for continuation via conversation_id. These details are useful but not exhaustive (e.g., no mention of output_path creation).

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

Conciseness4/5

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

The description is well-structured with clear sections (purpose, when-to-use, dialogue modes, provider selection, usage pattern, returns). It is concise and front-loaded with essential information. The usage pattern could be slightly shorter, but overall it efficiently conveys the tool's workflow.

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?

Given the tool's complexity (conversational image generation with many parameters and multi-turn refinement), the description covers core concepts, when to use, dialogue modes, provider locking, and continuation pattern. The output schema exists, so return details are not needed. It lacks discussion of some advanced parameters (e.g., reference_images, input_image_file_id), but schema handles those. It is sufficient for an AI agent to select and invoke.

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 0% (main description does not detail individual parameters), but the schema itself has thorough descriptions for all parameters. The description adds some context for 'dialogue_mode' (enum values) but largely repeats schema info. Baseline is 3 due to high schema coverage, and no significant extra meaning is added.

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 tool's purpose: 'Generate images conversationally with iterative refinement.' It specifies the resource (images) and the verb (generate with conversation), and distinguishes from sibling tools like 'generate_image' by emphasizing conversation and iterative refinement. The dialogue modes further clarify the scope.

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 lists 'USE THIS TOOL when:' conditions, such as vague prompts, iterative refinement, or user asking for guidance. It does not directly state when not to use it (e.g., when prompt is clear and no refinement needed), but the context effectively implies when alternatives like 'generate_image' are better. It also covers dialogue modes and provider selection, offering solid guidance.

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

edit_imageA

Edit an existing image using OpenAI gpt-image-2's /images/edits endpoint.

This is the right tool for:

  • Image-to-image refinement (OpenAI's answer to reference images)

  • Inpainting with a mask (paint over regions while preserving the rest)

  • Sequential/cumulative edits that preserve unchanged pixels

  • Brand-accurate modifications to existing images

Key features of gpt-image-2 editing:

  • input_fidelity='high' (default) keeps unchanged pixels constant — critical for multi-step refinement where each edit should build on the last without drift.

  • Full control over quality, background, output_format, and compression.

  • Supports optional PNG mask (transparent pixels are the edit region).

Typical workflow:

  1. Generate or obtain a base image (path on disk)

  2. Call edit_image with prompt='change the sky to sunset'

  3. Take the output path, call edit_image again with next instruction

  4. Repeat — each step preserves pixels outside the described change

Args: params: Edit parameters including prompt, image_path, and options.

Returns: Formatted response with edited image path and metadata.

ParametersJSON Schema
NameRequiredDescriptionDefault
paramsYes

Output Schema

ParametersJSON Schema
NameRequiredDescription
resultYes

TDQS

A5/5.0
Behavior5/5

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

Discloses key behavioral traits: uses /images/edits endpoint, default high input fidelity to preserve pixels, mask support, sequential workflow. Annotations (readOnlyHint=false, destructiveHint=false) are consistent; description adds context about mutable but non-destructive 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?

Well-structured with bullet points and sections (key features, typical workflow). No fluff; each sentence adds valuable information. Appropriate length given tool complexity.

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?

Covers use cases, workflow, and key features comprehensively. With an output schema present, return value explanation is unnecessary. The description is self-contained for correct invocation.

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

Parameters5/5

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

Although the tool has a single 'params' object with 0% description coverage at top level, the nested schema thoroughly documents all parameters. The description adds value by explaining key parameters like input_fidelity and mask_path in context, aiding interpretation beyond 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 clearly states it edits existing images using OpenAI's gpt-image-2 endpoint. It lists specific use cases (image-to-image refinement, inpainting, sequential edits) that distinguish it from sibling tools like generate_image or conversational_image, which focus on generation or conversation.

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?

Explicit guidance under 'This is the right tool for:' with bullet points covering refinement, inpainting, sequential edits, and brand modifications. It implies not for from-scratch generation (handled by generate_image). The workflow description further clarifies when to use.

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

estimate_costA
Read-onlyIdempotent

Estimate the cost of generating an image without generating it.

Runs the same provider auto-selection as generate_image (unless you pin a provider) and looks up an approximate price from a local pricing table. Useful for comparing providers/qualities before committing.

The figure is a ballpark — real cost depends on live provider pricing and, for OpenAI, actual image output tokens.

Args: params: Prompt plus optional provider/quality/size/n.

Returns: A formatted cost estimate.

ParametersJSON Schema
NameRequiredDescriptionDefault
paramsYes

Output Schema

ParametersJSON Schema
NameRequiredDescription
resultYes

TDQS

A4.4/5.0
Behavior5/5

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

Annotations already indicate readOnlyHint and idempotentHint. The description adds behavioral details: it runs the same provider auto-selection as generate_image, uses a local pricing table, and notes the estimate is a ballpark. No contradictions.

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

Conciseness4/5

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

The description is well-structured: starts with purpose, then explanation, caveats, and finally Args/Returns. It is slightly verbose but front-loaded with key information. A bit more conciseness could improve it.

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 simplicity of the tool (cost estimation with no side effects), the description covers all essential aspects: what it does, how it works, caveats, and return format (via output schema). With annotations and output schema present, no gaps remain.

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 description's Args section briefly lists parameters but adds little new meaning beyond the schema's own descriptions. The schema already provides detailed descriptions for each parameter. Schema coverage is 0% by context definition, but the schema itself is informative, so the description does not compensate for missing schema details.

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 tool's purpose: estimating the cost of generating an image without actually generating it. It uses specific verb 'estimate' and resource 'cost', and distinguishes it from siblings like generate_image by explicitly noting it does not generate.

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 explains when to use: before generating, for comparing providers/qualities. It implies not to use for actual generation, but does not explicitly state when not to use or list alternatives beyond the tool itself. However, the sibling list provides context.

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

generate_imageB

Generate an image using the best available provider.

Automatic Provider Selection: The server analyzes your prompt and automatically selects the best provider:

  • OpenAI GPT-Image-1 is auto-selected for:

    • Text-heavy images (menus, posters, infographics)

    • Comics with dialogue or speech bubbles

    • Technical diagrams with labels

    • Marketing materials requiring precise text

  • Gemini Nano Banana Pro is auto-selected for:

    • Photorealistic portraits and headshots

    • Product photography

    • High resolution (4K) output

    • Images using reference images for consistency

    • Real-time data visualization (weather, stocks)

Examples:

  • "Create a menu card for an Italian restaurant" → OpenAI (text rendering)

  • "Professional headshot with studio lighting" → Gemini (photorealism)

  • "Infographic explaining photosynthesis" → OpenAI (diagram + text)

  • "Product shot of perfume floating on water" → Gemini (product photography)

Override Selection: Set provider to 'openai' or 'gemini' to override auto-selection.

Args: params: Image generation parameters including prompt and optional settings.

Returns: Formatted response with image path and metadata.

ParametersJSON Schema
NameRequiredDescriptionDefault
paramsYes

Output Schema

ParametersJSON Schema
NameRequiredDescription
resultYes

TDQS

B3.4/5.0
Behavior3/5

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

Annotations exist but are minimal (readOnlyHint=false, etc.). Description adds value by explaining auto-selection behavior and provider strengths. However, it does not disclose important behaviors like file saving (implied by output_path), potential latency, or cost implications. No contradiction with annotations.

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

Conciseness4/5

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

The description is well-structured with headings, lists, and examples. It is front-loaded with the main purpose. However, it is somewhat lengthy with provider comparisons that could be condensed. Overall, sentences earn their place.

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?

Given the complexity (multiple providers, many parameters, auto-selection), the description explains the selection logic and provides examples. It mentions override and return format. An output schema exists to handle return details. It is fairly complete for an agent to understand the tool's behavior.

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

Parameters2/5

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

Schema coverage for the top-level param 'params' is 0% (no description), and the description only repeats 'Image generation parameters including prompt and optional settings' – adding no new meaning. While nested properties have descriptions in the schema, the description fails to compensate for the top-level lack of 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 clearly states the tool generates an image using the best available provider, with specific verb 'Generate' and resource 'image'. It distinguishes from siblings by focusing on single image generation with auto-selection, while siblings like 'edit_image' and 'conversational_image' imply 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 Guidelines2/5

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

The description provides detailed guidance on when to use each provider within the tool, but offers no guidance on when to choose this tool over sibling tools like 'edit_image' or 'generate_image_batch'. An agent would need to infer from the tool name and purpose.

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

generate_image_batchA

Generate many images concurrently from a list of prompts.

Each item runs through the same auto provider selection as generate_image, bounded by max_concurrency. Per-item failures are isolated — one bad prompt does not fail the whole batch. Returns every result (saved paths plus any per-item errors).

Use this instead of calling generate_image in a loop: 8 prompts that would take ~4 minutes serially complete in roughly one generation's time (subject to max_concurrency and provider rate limits).

Args: params: The batch (items + concurrency + optional default provider).

Returns: A formatted summary of all results.

ParametersJSON Schema
NameRequiredDescriptionDefault
paramsYes

Output Schema

ParametersJSON Schema
NameRequiredDescription
resultYes

TDQS

A4.9/5.0
Behavior5/5

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

Annotations indicate non-readonly, non-destructive, non-idempotent, open-world. Description adds concurrency bounds, failure isolation, rate limit dependency, and result format, providing substantial behavioral context beyond 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?

Well-structured with summary, args, and returns. Every sentence adds value; no redundancy.

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?

Covers inputs, behavior, concurrency, error handling, and return format. With output schema present, it provides complete guidance for a batch image generation 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?

Top-level 'params' description is brief, but the nested schema for `BatchGenerationInput` has detailed field descriptions. Tool description adds context about batch structure and default provider, complementing the schema.

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?

Clearly states the tool generates many images concurrently from a list of prompts. Distinguishes from siblings like `generate_image` by mentioning batch processing and concurrency.

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?

Explicitly advises using this tool instead of calling `generate_image` in a loop, with a concrete performance example. Also describes per-item failure isolation.

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

list_conversationsA
Read-onlyIdempotent

List saved image generation conversations.

Returns recent conversations that can be continued for refinement. Each conversation tracks the provider used and generation history.

Args: params: Options for filtering and formatting the list.

Returns: List of conversations with metadata.

ParametersJSON Schema
NameRequiredDescriptionDefault
paramsYes

Output Schema

ParametersJSON Schema
NameRequiredDescription
resultYes

TDQS

A3.8/5.0
Behavior3/5

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

Annotations already indicate read and idempotent. The description adds that results are 'recent' and can be 'continued for refinement', which provides some behavioral context beyond the annotations. However, it doesn't detail behavior like empty results, ordering, or response structure.

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 concise: four sentences total, with the core purpose in the first sentence. No extraneous information. All sentences add value.

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 list tool, the description covers purpose and key traits (recent, continuable, tracks provider/history). It lacks details on pagination behavior and ordering, and the output format is only implied via the parameter. Still, it is mostly sufficient given the annotations and schema.

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 description only says 'params: Options for filtering and formatting the list.' This is vague and does not add meaning beyond the input schema, which already describes each parameter. With 0% schema description coverage, the description fails to compensate, but the schema itself is sufficient.

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 tool lists saved image generation conversations, using specific verb 'list' and resource 'conversations'. It distinguishes from siblings as no other list tool exists. The purpose is unambiguous.

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 implies the tool is used to retrieve recent conversations for refinement, but provides no explicit guidance on when to use it versus other tools or when not to use it. No alternatives are mentioned.

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

list_gemini_modelsA
Read-onlyIdempotent

List available Gemini models that support image generation.

Queries the Gemini API to show which models are available for image generation with your API key. Useful for troubleshooting or choosing alternative models.

Returns: List of available Gemini image models with their capabilities.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

Output Schema

ParametersJSON Schema
NameRequiredDescription
resultYes

TDQS

A4.3/5.0
Behavior3/5

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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint. The description adds that it queries the Gemini API and returns capabilities, but does not provide additional behavioral details 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 concise and well-structured, with a clear purpose, action, return description, and use case. Every sentence adds value.

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 zero parameters and presence of an output schema, the description fully covers the tool's purpose and typical use case without needing further elaboration.

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?

There are no parameters, so the baseline is 4. The description does not need to add parameter semantics, and it does not attempt 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 clearly states it lists available Gemini models that support image generation. This verb-noun pair is specific and distinguishes it from siblings like 'generate_image' or 'list_providers'.

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 mentions it is useful for troubleshooting or choosing alternative models, providing clear context. It does not explicitly state when not to use it, but the context of sibling tools offers implied guidance.

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

list_providersA
Read-onlyIdempotent

List available image generation providers and their capabilities.

Returns a comparison of available providers including:

  • Which providers have API keys configured

  • Best use cases for each provider

  • Feature comparison (text rendering, resolution, etc.)

Use this to understand which provider to choose for your task.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

Output Schema

ParametersJSON Schema
NameRequiredDescription
resultYes

TDQS

A4.5/5.0
Behavior4/5

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

Annotations already declare readOnlyHint=true and idempotentHint=true, but the description adds value by detailing the return content: API key configuration, best use cases, and feature comparison. No contradictions.

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 concise, with a clear lead sentence and bullet points for output details. Every sentence adds value, and there is no redundancy.

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?

The description adequately explains the tool's purpose and what the output includes, even without needing to detail parameters. Given the presence of an output schema, the description is complete.

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?

There are no parameters, and schema coverage is 100%. With zero parameters, the baseline is 4, and the description does not need to add parameter details.

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 explicitly states 'List available image generation providers and their capabilities', clearly identifying the verb (list) and resource (providers with capabilities). This distinguishes it from sibling tools like generate_image or edit_image, which perform 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 advises 'Use this to understand which provider to choose for your task', providing clear context for when to use this tool. While it doesn't list explicit alternatives or when-not-to-use, the context of sibling tools makes the usage well implied.

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. 8 tool updatesv0.3.0
    • First observedconversational_image
    • First observededit_image
    • First observedestimate_cost
    • First observedgenerate_image
    • First observedgenerate_image_batch
    • First observedlist_conversations
    • First observedlist_gemini_models
    • First observedlist_providers

TDQS

A4.1/5.0

Scored across 8 tools

Disambiguation5/5

Each tool has a clearly distinct purpose: direct generation, conversational refinement, editing, batch generation, cost estimation, and listing of conversations/models/providers. Overlaps are minimal and resolved by detailed descriptions.

Naming Consistency4/5

Most tools follow verb_noun snake_case (e.g., edit_image, generate_image), but 'conversational_image' uses an adjective instead of a verb, creating a slight inconsistency.

Tool Count5/5

With 8 tools covering generation, editing, batch processing, cost estimation, and listing functions, the count is well-scoped for an image generation server without being too many or too few.

Completeness4/5

The tool surface covers core generation, editing, batch, and estimation needs. Minor gaps exist (e.g., no deletion tool or detailed image metadata viewer), but the essential workflows are supported.

Maintenance

ActivitySlowing
ResponsivenessNo issues

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