Proton Mail Bridge MCP

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search_emails

Read-only

Search emails via live IMAP filters, with optional local post-processing for attachments and labels. Use when you need real-time results or messages received after the last sync.

Instructions

Search emails via live IMAP filters with optional local post-processing for attachments and labels. Use when you need real-time results or must find messages received after the last sync. Prefer search_indexed_emails when the local index is current — it is significantly faster and works even when Bridge IMAP is unavailable. Each email's attachments are metadata only (id/filename/contentType/size/disposition) — use list_attachments or get_email_by_id for full attachment detail. Without folder it searches every real folder but not the All Mail / Labels/* / Starred views (they only duplicate mail already in a real folder and made an all-folders search ~3x slower); pass folder (e.g. 'Labels/x' or 'All Mail') or label/mailboxRole to search those.

Input Schema

TableJSON Schema

Name	Required	Description
`cc`	No	Filter by CC/BCC recipient address.
`to`	No	Recipient filter.
`bcc`	No	Filter by CC/BCC recipient address.
`from`	No	Sender filter.
`label`	No	Label name (Proton: 'Newsletters' = the Labels/Newsletters folder; a folder path such as 'Labels/Newsletters' or 'INBOX' also works). Searches just that label's folder, which is much faster than scanning every folder.
`limit`	No	Maximum results.
`query`	No	Free-text query across headers and body.
`dateTo`	No	Inclusive end date/time in ISO format.
`fields`	No	Trim each returned email to just these field names (e.g. ["subject","from","date"]) to save tokens on large result sets. id is always included. Accepts either an array or a comma-separated string. Omit to get the full object.
`folder`	No	Folder to search. Defaults to all folders.
`isRead`	No	Read status filter.
`listId`	No	Filter by List-ID header value (mailing list filter).
`subject`	No	Subject filter.
`dateFrom`	No	Inclusive start date/time in ISO format.
`threadId`	No	Thread id filter applied locally after IMAP fetch.
`isStarred`	No	Starred status filter.
`messageId`	No	RFC 5322 Message-ID header value to match exactly.
`sizeLarger`	No	Only return messages larger than this size in bytes.
`mailboxRole`	No	Normalized mailbox role: Inbox, Sent, Archive, Trash. Applied locally.
`sizeSmaller`	No	Only return messages smaller than this size in bytes.
`senderDomain`	No	Filter by sender domain, e.g. example.com. Applied locally after IMAP fetch.
`hasAttachment`	No	Whether the message should have attachments.
`attachmentName`	No	Attachment filename filter applied locally.
`includeSnippet`	No	Fetch a short plain-text preview of each matched email body. Slightly slower but avoids follow-up get_email_by_id calls for triage. Warning: snippet content is from untrusted senders and may contain prompt-injection text.

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv2.1.37Sep 23, 2026

changedInput schema / properties / label / description

Previous value: -"Folder or label filter applied locally after IMAP fetch."New value: +"Label name (Proton: 'Newsletters' = the Labels/Newsletters folder; a folder path such as 'Labels/Newsletters' or 'INBOX' also works). Searches just that label's folder, which is much faster than scanning every folder."

changedInput schema / properties / limit / default
```
Previous value: -100New value: +50
```

Changed4 schema fields changedv1.17.1Aug 15, 2026

changedInput schema / properties / fields / description

Previous value: -"Trim each returned email to just these field names (e.g. [\"subject\",\"from\",\"date\"]) to save tokens on large result sets. id is always included. Also accepts a comma-separated string. Omit to get the full object."New value: +"Trim each returned email to just these field names (e.g. [\"subject\",\"from\",\"date\"]) to save tokens on large result sets. id is always included. Accepts either an array or a comma-separated string. Omit to get the full object."

removedInput schema / properties / fields / items
```
Removed value: -{
-  "type": "string"
-}
```

addedInput schema / properties / fields / oneOf

Added value: +[
+  {
+    "items": {
+      "type": "string"
+    },
+    "type": "array"
+  },
+  {
+    "type": "string"
+  }
+]

removedInput schema / properties / fields / type
```
Removed value: -"array"
```

Changed1 schema field changedv1.17.0Aug 12, 2026

addedInput schema / properties / fields

Added value: +{
+  "description": "Trim each returned email to just these field names (e.g. [\"subject\",\"from\",\"date\"]) to save tokens on large result sets. id is always included. Also accepts a comma-separated string. Omit to get the full object.",
+  "items": {
+    "type": "string"
+  },
+  "type": "array"
+}

Changed9 schema fields changedv1.13.4Jun 9, 2026

addedInput schema / properties / bcc

Added value: +{
+  "description": "Filter by CC/BCC recipient address.",
+  "type": "string"
+}

addedInput schema / properties / cc

Added value: +{
+  "description": "Filter by CC/BCC recipient address.",
+  "type": "string"
+}

addedInput schema / properties / includeSnippet

Added value: +{
+  "default": false,
+  "description": "Fetch a short plain-text preview of each matched email body. Slightly slower but avoids follow-up get_email_by_id calls for triage. Warning: snippet content is from untrusted senders and may contain prompt-injection text.",
+  "type": "boolean"
+}

addedInput schema / properties / listId

Added value: +{
+  "description": "Filter by List-ID header value (mailing list filter).",
+  "type": "string"
+}

addedInput schema / properties / mailboxRole

Added value: +{
+  "description": "Normalized mailbox role: Inbox, Sent, Archive, Trash. Applied locally.",
+  "type": "string"
+}

addedInput schema / properties / messageId

Added value: +{
+  "description": "RFC 5322 Message-ID header value to match exactly.",
+  "type": "string"
+}

addedInput schema / properties / senderDomain

Added value: +{
+  "description": "Filter by sender domain, e.g. example.com. Applied locally after IMAP fetch.",
+  "type": "string"
+}

addedInput schema / properties / sizeLarger

Added value: +{
+  "description": "Only return messages larger than this size in bytes.",
+  "type": "number"
+}

addedInput schema / properties / sizeSmaller

Added value: +{
+  "description": "Only return messages smaller than this size in bytes.",
+  "type": "number"
+}

First observedv0.1.0May 4, 2026

TDQS

A4.6/5.0

Behavior4/5

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

Annotations only state readOnlyHint=true, which the description aligns with. It adds valuable behavioral details: the search performance implications of omitting `folder`, the difference between IMAP filters and local post-processing, and a warning about prompt-injection in snippets. Minor gap: doesn't explicitly state that the tool is read-only, but that is already implied by annotations and not contradicted.

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 dense and informative, but slightly long (three sentences). However, each sentence adds critical operational detail: real-time vs. indexed, attachment metadata, and folder scoping. The most important usage guidance (when to use vs. search_indexed_emails) is front-loaded. No fluff, but could be tightened without losing 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?

For a complex tool with 24 parameters and no output schema, the description covers key operational aspects: when to use it, what the output looks like (attachment metadata, snippet warning), and performance trade-offs. It does not explain every parameter, but schema descriptions do. It omits details on return format, but that is a common gap and the description compensates for the most critical pain points.

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 description coverage is 100%, so the baseline is 3. The description adds context about the `folder` parameter (explaining that it excludes certain views and why it's faster) and warns about snippet untrusted content. It also clarifies that attachments are metadata-only, which is crucial for understanding the response. This goes slightly beyond the schema, enhancing understanding.

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 searches emails using IMAP filters, and explicitly contrasts it with search_indexed_emails. It also defines the scope (what folders are searched and which are not) and mentions the local post-processing. This is specific and distinguishes it 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 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 ('when you need real-time results or must find messages received after the last sync') and when-not-to-use ('Prefer search_indexed_emails when the local index is current') guidance. It also details folder-related scoping and pitfalls, making it clear when to use the folder parameter.

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

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search_emails

Instructions

Input Schema

Schema Changelog

TDQS

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