ZeptoMail Templates MCP
ZeptoMail Templates MCP
AIエージェント(opencode、Claude Desktop、Cursorなど)が、Zohoアカウント内のすべてのZeptoMailエージェントにわたってメールテンプレートを閲覧・管理できるようにするMCPサーバーです。
このサーバーは、メールの送信、エージェントの作成・削除、Send Mailトークンの公開、ドメインの管理を意図的に行いません。エージェント一覧の読み取りとテンプレートの管理のみを行います。
クイックスタート(ローカル、約5分)
1. サーバーをインストールする
npm i -g zeptomail-mcpこれで、PATHにzeptomail-mcpコマンドが追加されます。ローカルクローン(リポジトリ)から実行したい場合は、この手順をスキップしてください(node /path/to/zeptomail-mcp/dist/src/server.js)。
2. Zoho OAuthアプリを作成する
Zoho APIコンソールを開きます。
サーバーベースのアプリケーションを作成します:
クライアント名:
zeptomailmcp(ハイフン不可 — Zohoが拒否します)ホームページURL:任意、例:
https://github.com/P4rthPat3l/zeptomail-mcp認可リダイレクトURI:
http://localhost:4567/callback
クライアントIDとクライアントシークレットを控えます。
セルフクライアントも利用可能です。リダイレクトURIフィールドがないため、手順2の代わりにそのコード生成タブを使用します(下記のセルフクライアントのセットアップを参照)。
3. リフレッシュトークンを取得する
ZOHO_CLIENT_ID=<your-client-id> ZOHO_CLIENT_SECRET=<your-secret> zeptomail-mcp-loginブラウザでZohoの同意画面が開き、スコープZeptomail.MailAgents.READ + Zeptomail.MailTemplates.Allが表示されます。承認すると、スクリプトがリフレッシュトークンを出力します。
グローバルインストールではなくローカルクローンから実行している場合、同じコマンドは
npm run loginです。
4. MCPホストを設定する
Zohoの認証情報をホスト設定にインラインで渡すか、.envファイルから読み込むことができます(設定ファイル自体にシークレットを含めないため)。どちらでも動作します。いずれかを選択してください。
オプションA — .envファイルから読み込む(推奨)
シークレットを.envファイルに保存します(gitignoreに追加してください — 認証情報です):
# .env
ZOHO_CLIENT_ID=<your-client-id>
ZOHO_CLIENT_SECRET=<your-secret>
ZOHO_REFRESH_TOKEN=<your-refresh-token>
ZOHO_ACCOUNTS_URL=https://accounts.zoho.com次に、--env-fileでサーバーをそのファイルに指定します。パスはホストの作業ディレクトリからの相対パスで解決されます。不明な場合は絶対パスを使用してください。
opencode — opencode.json(または.opencode/opencode.json):
{
"mcp": {
"zeptomail": {
"type": "local",
"command": ["zeptomail-mcp", "--env-file=/absolute/path/to/.env"],
"enabled": true
}
}
}Claude Desktop — claude_desktop_config.json:
{
"mcpServers": {
"zeptomail": {
"command": "zeptomail-mcp",
"args": ["--env-file=/absolute/path/to/.env"]
}
}
}オプションB — ホスト設定にインラインで記述
opencode — opencode.json(または.opencode/opencode.json):
{
"mcp": {
"zeptomail": {
"type": "local",
"command": ["zeptomail-mcp"],
"enabled": true,
"environment": {
"ZOHO_CLIENT_ID": "...",
"ZOHO_CLIENT_SECRET": "...",
"ZOHO_REFRESH_TOKEN": "...",
"ZOHO_ACCOUNTS_URL": "https://accounts.zoho.com"
}
}
}
}Claude Desktop — claude_desktop_config.json:
{
"mcpServers": {
"zeptomail": {
"command": "zeptomail-mcp",
"env": {
"ZOHO_CLIENT_ID": "...",
"ZOHO_CLIENT_SECRET": "...",
"ZOHO_REFRESH_TOKEN": "...",
"ZOHO_ACCOUNTS_URL": "https://accounts.zoho.com"
}
}
}
}グローバルインストールではなくローカルクローンから実行する場合
ビルド済みランチャーをnodeで直接実行します。グローバルのzeptomail-mcpコマンドと同じように--env-fileを解析するため、フラグはスクリプトの後に置きます:
opencode(オプションAのenv-file):
["node", "/absolute/path/to/zeptomail-mcp/dist/src/cli.js", "--env-file=/absolute/path/to/.env"]opencode(オプションBのインライン):
["node", "/absolute/path/to/zeptomail-mcp/dist/src/cli.js"]+environmentブロックClaude Desktop:
"command": "node"、"args": [".../dist/src/cli.js", "--env-file=..."](またはenvブロック付きで[".../dist/src/cli.js"]のみ)
5. 使用する
エージェントにツールの呼び出しを依頼します:
「ZeptoMailエージェントを一覧表示して」
「エイリアス
team_inviteのテンプレートを探して」「サンドボックスエージェントのOTPテンプレートを表示して」
Related MCP server: mcp-imap
セルフクライアントのセットアップ
セルフクライアントにはリダイレクトURIがないため、zeptomail-mcp-loginはそのコールバックを受け取れません。代わりに:
APIコンソール → セルフクライアント → コード生成。
スコープ:
Zeptomail.MailAgents.READ,Zeptomail.MailTemplates.All→ CREATE。生成されたコードをコピーして交換します:
curl -X POST https://accounts.zoho.com/oauth/v2/token \
-d "code=<generated code>" \
-d "client_id=<client id>" \
-d "client_secret=<client secret>" \
-d "grant_type=authorization_code" \
-d "redirect_uri=https://api-console.zoho.com/"JSONレスポンスにrefresh_tokenが含まれます。
ツール
MCPツール | 目的 | データ変更 |
| アクセス可能なエージェントと正確なエージェントキー/エイリアスを一覧表示 | いいえ |
| 指定した1つのエージェント内のテンプレートを一覧表示 | いいえ |
| 名前/エイリアス/件名で1つのエージェントまたは全エージェントを検索 | いいえ |
| 1つのエージェントから完全なテンプレートを1件読み取る | いいえ |
| 指定した1つのエージェントにテンプレートを作成 | はい |
| エージェント+古い書き込み保護付きの部分更新 | はい |
| エージェント/名前/タイムスタンプのチェック付きの完全削除 | はい |
書き込みツールには両方が必要です:
サーバー環境に
ZEPTOMAIL_MCP_ALLOW_WRITES=true。個々のツール呼び出しに
confirm=true。
また、すべての書き込みには、最新のzeptomail_list_agents呼び出しからの正確なagentKeyとexpectedAgentNameが必要です。更新/削除にはさらに、現在のテンプレートの安全値(expectedModifiedTime、expectedTemplateName)が必要です。これにより、古い読み取りが新しい編集を上書きすることはありません。
設定リファレンス
変数 | 必須 | デフォルト | 目的 |
| はい | — | Zoho OAuthアプリのクライアントID |
| はい | — | Zoho OAuthアプリのクライアントシークレット |
| はい (stdio) | — | 長期有効なトークン。サーバーはこれから1時間のアクセストークンを生成します |
| いいえ |
| Zohoデータセンター( |
| いいえ |
| ZeptoMail APIのベースURL |
| いいえ |
| 作成/更新/削除を有効にするには |
| いいえ | すべてのエージェント | カンマ区切りの |
| いいえ |
|
|
すべての変数は、プロセス環境変数(ホスト設定で設定)またはサーバーへの--env-file=<path>引数(上記のMCPホストの設定を参照)のいずれかで指定できます。プロセス変数が優先されます。ファイルは未設定の変数のみを補完します。
ホスト型(リモート)モード(OAuth 2.0 + PKCE)
共有/公開MCPエンドポイントの場合、ZEPTOMAIL_MCP_TRANSPORT=httpで実行します。サーバーはOAuth認可サーバーとなり、上流の認可サーバーとしてZohoにプロキシします:
MCP client ⇄ this MCP server (OAuth AS + resource server) ⇄ Zoho (upstream AS) ⇄ ZeptoMail APIZEPTOMAIL_MCP_TRANSPORT=http \
ZEPTOMAIL_MCP_SERVER_URL=https://mcp.example.com \
ZEPTOMAIL_MCP_PORT=3006 \
ZEPTOMAIL_MCP_TOKEN_STORE=/var/lib/zeptomail-mcp/tokens.json \
node dist/src/server.jsクライアントは
/.well-known/oauth-protected-resourceと/.well-known/oauth-authorization-serverでメタデータを検出し、動的に登録し、ブラウザで同意します。サーバーはクライアントのPKCE S256チャレンジと
access_type=offlineをZohoにリダイレクトし、サーバーのZohoクライアントシークレットでコードを交換し、クライアントごとのZohoリフレッシュトークンを保存します(サーバーから外部に出ることはありません)。各ユーザーのツールは、それぞれのZeptoMailアカウントで動作します。
ホスト設定(opencode):
{
"mcp": {
"zeptomail": {
"type": "remote",
"url": "https://mcp.example.com/mcp",
"oauth": {}
}
}
}ホスト型モードの要件:HTTPS(SDKはlocalhost以外の非HTTPS発行者URLを拒否します)、APIコンソールに登録されたZohoコールバックURI(https://mcp.example.com/callback)、永続的なトークンストア。サーバーを再起動すると発行済みトークンが無効になります — クライアントは一度再同意します。
開発
npm install
npm run typecheck
npm test
npm run buildセキュリティに関する注意
エージェントの検出は読み取り専用です。エージェントの作成、APIキーの生成、Send Mailトークンへのアクセスを行うツールはありません。
MCPはメールを送信しません。
ZEPTOMAIL_MCP_ALLOWED_AGENT_KEYSは、OAuthアカウントがより多くを表示できる場合でも、MCPが操作できるエージェントを制限します。リフレッシュトークンは長期有効な認証情報です。サーバー側に保管し、パスワードと同様に扱い、漏洩した場合はZohoコンソールで失効させてください。
Available Tools
8 toolszeptomail_create_templateCreate ZeptoMail templateA
Create a template in one explicit Agent. Requires agentKey plus expectedAgentName from a fresh zeptomail_list_agents call, server writes enabled, and confirm=true.
| Name | Required | Description | Default |
|---|---|---|---|
| confirm | No | ||
| subject | Yes | ||
| agentKey | Yes | Exact mailagent_key / Agent alias returned by zeptomail_list_agents. Never guess this value. | |
| htmlBody | No | ||
| textBody | No | ||
| templateName | Yes | ||
| templateAlias | No | ||
| expectedAgentName | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already convey that this is a write, non-idempotent, non-destructive operation. The description adds useful behavioral context beyond those hints: the agentKey must come from a fresh list call, server writes must be enabled, and confirm=true is required. No contradiction with annotations exists.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single dense sentence with no filler. It front-loads the action and immediately states the most important prerequisites and safety requirements. Every clause earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a mutating tool with no output schema and sparse parameter documentation, the description includes the critical preconditions to avoid mis-keying an Agent. However, it omits any guidance on the remaining parameters, expected response behavior, or duplicate-template handling, so it is only minimally complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 13%, so the description must compensate. It does helpfully explain agentKey, expectedAgentName, and confirm usage, but leaves templateName, subject, htmlBody, textBody, and templateAlias entirely to name-based inference. This is adequate but not thorough for an 8-parameter tool.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a clear verb-resource pair: create a template, and identifies the target scope as a specific ZeptoMail Agent. It is distinguishable from the list/get/update/delete siblings, though the phrase 'one explicit Agent' is slightly awkward and could be clearer.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives concrete invocation prerequisites: obtain agentKey and expectedAgentName from a fresh zeptomail_list_agents call, ensure server writes are enabled, and set confirm=true. It does not explicitly contrast this with zeptomail_update_template, but the prerequisites and confirmation gate provide strong usage direction.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
zeptomail_delete_templateDelete ZeptoMail templateADestructiveIdempotent
Permanently delete a template from one explicit Agent. Requires expectedAgentName, expectedTemplateName, and expectedModifiedTime from fresh reads. Requires writes enabled and confirm=true.
| Name | Required | Description | Default |
|---|---|---|---|
| confirm | No | ||
| agentKey | Yes | Exact mailagent_key / Agent alias returned by zeptomail_list_agents. Never guess this value. | |
| templateKey | Yes | ||
| expectedAgentName | Yes | ||
| expectedModifiedTime | Yes | ||
| expectedTemplateName | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate destructive and non-read-only behavior. The description adds valuable context: deletion is permanent, expected values must come from fresh reads to prevent stale operations, and confirm=true is required. This goes meaningfully beyond the structured annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three short sentences with no filler. The destructive action, freshness requirement, and confirmation gate are all stated efficiently and front-loaded.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a destructive tool with six parameters and no output schema, the description covers the critical preconditions: fresh reads, writes enabled, confirm=true, and explicit agent scope. It doesn't describe behavior when confirm=false or when expected values mismatch, but the essentials for safe invocation are present.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is only 17%, so the description must compensate. It does explain that expectedAgentName, expectedTemplateName, and expectedModifiedTime must come from fresh reads, and that confirm must be true. However, templateKey is left undocumented in both schema and description, so coverage is not complete.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly identifies the action ('Permanently delete'), the resource ('a template'), and the scope ('from one explicit Agent'). This distinguishes it from listing, getting, creating, and updating templates, even without naming a sibling.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives clear usage context: the tool should only be used after fresh reads, with writes enabled, and with confirm=true. It doesn't explicitly contrast with sibling tools, but the destructive delete semantics and prerequisites make the appropriate use case clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
zeptomail_export_templatesExport all ZeptoMail templates from one AgentARead-onlyIdempotent
Fetch every full template (HTML body, text body, subject, alias, attachments metadata) from one explicit Agent and return them as a single JSON dump. Read-only. Use when the caller wants to back up an Agent templates to local files; the caller writes the files itself — this tool returns the data, it does not write to disk.
| Name | Required | Description | Default |
|---|---|---|---|
| agentKey | Yes | Exact mailagent_key / Agent alias returned by zeptomail_list_agents. Never guess this value. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, and the description reinforces these by saying 'Read-only' and adding valuable clarification that the tool does not write to disk—the caller handles file writing. This goes beyond the annotations by explicitly addressing side-effect expectations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences deliver both the functional scope and the usage context with no wasted words. The key behavior is front-loaded, and the clarifying 'does not write to disk' earns its place in the same sentence.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple one-parameter, read-only export tool, the description covers what is returned, the scope, the caller's responsibility, and the primary use case. It does not describe output size or pagination, but the absence of an output schema and the straightforward nature of the operation make this adequate.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100% and the sole parameter agentKey is already well documented as an exact mailagent_key/alias returned by zeptomail_list_agents. The description mentions 'one explicit Agent' but adds no new parameter-level meaning beyond the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb 'Fetch' with a precise resource: every full template from one explicit Agent, returned as a single JSON dump. It lists the exact fields included, which clearly distinguishes it from sibling list/find/get tools even without naming them.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explicitly states the intended use case: backing up an Agent's templates to local files, and clarifies that the caller writes files while this tool only returns data. It does not explicitly name alternatives or say when not to use it, but the use-case framing provides clear directional guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
zeptomail_find_templatesFind ZeptoMail templatesARead-onlyIdempotent
Search template name, alias and subject. Omit agentKey to search across every accessible Agent; provide agentKey to restrict the search to one Agent. Results always include the owning Agent.
| Name | Required | Description | Default |
|---|---|---|---|
| query | Yes | ||
| agentKey | No | Exact mailagent_key / Agent alias returned by zeptomail_list_agents. Never guess this value. | |
| maxResults | No |
TDQS
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 behavioral context beyond that: the scope of the search with and without agentKey, and that results always include the owning Agent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three sentences, each earning its place: the search action, the scoping behavior, and the guaranteed result field. No redundancy or filler.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the safe annotations and simple parameter set, the description covers the essential behavior: what is searched, how to scope the search, and what results always include. The absence of an output schema is partially mitigated by the 'owning Agent' note, though full result shape is still not described.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 33%, but the description compensates by explaining that query searches name, alias, and subject, and by clarifying agentKey's optionality. maxResults is not mentioned, though its schema defaults, min, and max make its behavior reasonably inferable.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description opens with a specific verb and resource: 'Search template name, alias and subject.' It clearly separates this search-oriented tool from sibling list/get/create/update/delete operations, and the agentKey scoping further sharpens its purpose.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives clear context for use: omit agentKey to search all accessible Agents, or provide it to restrict to one Agent. It does not explicitly name alternatives or state when not to use the tool, but the search scope guidance is straightforward.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
zeptomail_get_templateGet ZeptoMail templateARead-onlyIdempotent
Fetch one complete template from one explicit Agent by exact template key. Always call this before updating or deleting.
| Name | Required | Description | Default |
|---|---|---|---|
| agentKey | Yes | Exact mailagent_key / Agent alias returned by zeptomail_list_agents. Never guess this value. | |
| templateKey | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds a workflow rule ('before updating or deleting') and indicates the return is a 'complete template', but does not describe error conditions, auth, or pagination. This is adequate given annotation coverage, but not richly transparent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences with no fluff. The primary action is front-loaded, and the workflow requirement is stated immediately after. Every word earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple read-only fetch with two required parameters and no output schema, the description covers what is returned ('complete template'), the key inputs, and when to call it. It does not enumerate the template fields or failure modes, but that level of detail is not essential for invoking it correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The schema already gives a thorough description for agentKey, but templateKey is only a bare string. The description adds that both keys must be 'exact' and that agentKey comes from zeptomail_list_agents, but it does not say where templateKey originates (e.g., zeptomail_list_templates). With 50% schema coverage, the description partially compensates but leaves a meaningful gap.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific verb ('Fetch'), a clear resource ('one complete template'), and the selection criteria ('from one explicit Agent by exact template key'). It clearly distinguishes this tool from siblings like list_templates or find_templates by emphasizing exactness and a single full template, and from update/delete by explicitly positioning it as a prerequisite before those operations.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The directive 'Always call this before updating or deleting' provides explicit when-to-use guidance and places this tool in a workflow. It does not explicitly state when not to use it or name alternatives for searching/listing, but the context is clear enough for an agent to select this over mutation or search tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
zeptomail_list_agentsList ZeptoMail AgentsARead-onlyIdempotent
List accessible Agents in the ZeptoMail account. Returns each Agent name and exact mailagent_key (Agent alias). Always use the returned key for template tools; do not guess Agent identifiers.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare this as read-only and idempotent. The description adds meaningful behavioral context by explaining that the tool returns exact mailagent_key values and warning against guessing identifiers, which goes beyond the annotation baseline.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two sentences with no filler. It front-loads the primary action, then provides the essential output detail and a practical warning.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given that there is no output schema, the description adequately explains the return contents: Agent name and exact mailagent_key. It also explains why this matters for subsequent template tools, making it complete for a simple list operation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The tool has zero parameters, so no parameter documentation is needed. The description correctly focuses on what the tool returns rather than input semantics.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific verb and resource: 'List accessible Agents in the ZeptoMail account.' It also clarifies the exact output value, the mailagent_key (Agent alias), and distinguishes this tool from the template-focused siblings.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives a clear usage directive: always use the returned key for template tools and do not guess Agent identifiers. It doesn't name explicit alternatives or exclusion conditions, but the context makes the intended workflow clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
zeptomail_list_templatesList ZeptoMail templatesARead-onlyIdempotent
List templates in one explicit ZeptoMail Agent. Use zeptomail_list_agents first and pass the exact returned mailagent_key.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | ||
| offset | No | ||
| agentKey | Yes | Exact mailagent_key / Agent alias returned by zeptomail_list_agents. Never guess this value. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already communicate readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds that the tool is scoped to one explicit Agent and depends on the prior agent lookup. It does not disclose pagination, ordering, or return format, but these are minor given 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.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two tight sentences with no filler. The core action and the most important usage note are front-loaded, and every word contributes to correct invocation.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a read-only listing tool, the critical dependency on zeptomail_list_agents is explicit and the schema covers pagination bounds. The absence of an output schema means the return shape is not described, which is a minor gap but not a blocker since the resource and listing behavior are clear.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 33%, and the description mostly restates what the agentKey schema field already says: pass the exact mailagent_key returned by zeptomail_list_agents. It adds little meaning for limit and offset, which rely on names and numeric constraints rather than explanatory descriptions.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific verb and resource: 'List templates in one explicit ZeptoMail Agent.' It also conveys the agent-scoped nature, which separates it from listing agents or cross-agent template operations. However, it does not explicitly distinguish itself from sibling tools like zeptomail_find_templates or zeptomail_export_templates.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
It gives a clear prerequisite: use zeptomail_list_agents first and pass the exact returned mailagent_key. This is strong contextual guidance for when this tool should be called. It does not, however, state when to prefer alternatives such as zeptomail_find_templates instead.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
zeptomail_update_templateUpdate ZeptoMail templateADestructiveIdempotent
Partially update a template in one explicit Agent. Requires expectedAgentName and expectedModifiedTime from fresh reads so a stale or wrong-Agent edit is rejected. Requires writes enabled and confirm=true.
| Name | Required | Description | Default |
|---|---|---|---|
| confirm | No | ||
| subject | No | ||
| agentKey | Yes | Exact mailagent_key / Agent alias returned by zeptomail_list_agents. Never guess this value. | |
| htmlBody | No | ||
| textBody | No | ||
| templateKey | Yes | ||
| templateName | No | ||
| templateAlias | No | ||
| expectedAgentName | Yes | ||
| expectedModifiedTime | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark this as non-read-only and destructive. The description adds meaningful guardrail context beyond annotations: stale or wrong-Agent edits are rejected, confirmation is mandatory, and writes must be enabled. This goes beyond what the schema or annotations alone convey.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two dense sentences with no filler. The core action is front-loaded, and the critical requirements are stated immediately after, making it easy for an agent to parse and act on.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a destructive, mutation-focused tool with 10 parameters and no output schema, the description covers the key invocation requirements: partial update, single Agent, fresh expected values, writes enabled, and confirmation. It does not describe return values or detailed error behavior, but the lack of an output schema lowers that burden.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 10%, so the description must compensate. It usefully explains expectedAgentName and expectedModifiedTime as optimistic-concurrency guards and mentions confirm=true, but it does not clarify the semantics of subject, htmlBody, textBody, templateName, or templateAlias beyond their raw string types.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb and resource: 'Partially update a template in one explicit Agent.' It distinguishes this from create, delete, get, and export sibling tools by emphasizing partial update and single-Agent scope, so an agent can tell what the tool is for without opening the schema.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description clearly states preconditions: expectedAgentName and expectedModifiedTime must come from fresh reads, writes must be enabled, and confirm=true. It shows when to use the tool but does not explicitly contrast it with related tools or state when not to use it.
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.
8 tool updates
v0.3.7- First observed
zeptomail_create_template - First observed
zeptomail_delete_template - First observed
zeptomail_export_templates - First observed
zeptomail_find_templates - First observed
zeptomail_get_template - First observed
zeptomail_list_agents - First observed
zeptomail_list_templates - First observed
zeptomail_update_template
TDQS
Scored across 8 tools
Each tool targets a distinct resource and action: agents vs templates, and list/search/get/export/create/update/delete are clearly separated. Even the similar list_templates and find_templates are disambiguated by one being an enumeration and the other being a search across name, alias, and subject.
All tool names use the consistent zeptomail_ prefix followed by verb_noun snake_case, such as zeptomail_list_agents and zeptomail_update_template. The naming pattern is uniform and predictable across the entire set.
Eight tools is well-scoped for a ZeptoMail template management server. Each tool covers a necessary operation without redundancy or bloat, and the count is within the ideal range for a focused domain server.
The tool surface provides full lifecycle coverage for templates: list, search, get, export, create, update, and delete. Agent enumeration supports the required context for template operations, so agents can accomplish end-to-end template management without dead ends.
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