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Search Message Snippets

mailbox_search_message_snippets

Read-onlyIdempotent

Search email inboxes by query text to retrieve message snippets. Narrow with sender, recipient, folder, date, unread, attachment, keyword, or size filters; use returned IDs to read full messages.

Instructions

Use this to search message snippets by query text. Narrow with folder_id, keyword/not_keyword, dates, sender/recipient, unread state, or has_attachment; use returned message IDs with a read tool before making content-specific claims.

Input Schema

TableJSON Schema

Name	Required	Description
`q`	Yes	Search text used to generate snippets.
`cc`	No	Filter by CC recipient email address or display name.
`to`	No	Filter by To recipient email address or display name.
`bcc`	No	Filter by BCC recipient email address or display name.
`body`	No	Filter by message body text.
`from`	No	Filter by sender email address or display name.
`after`	No	Filter to messages after this ISO 8601 timestamp.
`limit`	No	Maximum results (default 50, max 100).
`before`	No	Filter to messages before this ISO 8601 timestamp.
`keyword`	No	Require this message keyword, such as `$seen`.
`subject`	No	Filter by subject text.
`folder_id`	No	Filter to messages in this folder ID.
`is_unread`	No	When true, only return unread messages.
`mailbox_id`	No	Mailbox public ID to target when the credential grants access to more than one mailbox. Omit when the credential is scoped to exactly one mailbox.
`header_name`	No	Header name to match with `header_value`.
`message_ids`	No	Comma-separated message IDs, maximum 100.
`not_keyword`	No	Exclude messages with this keyword.
`header_value`	No	Header value to match with `header_name`.
`has_attachment`	No	When true, only return messages with attachments.
`max_size_bytes`	No	Maximum message size in bytes.
`min_size_bytes`	No	Minimum message size in bytes.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedv1.0.8Sep 15, 2026

addedOutput schema / $schema

Added value: +"https://json-schema.org/draft/2020-12/schema"

removedOutput schema / additionalProperties
```
Removed value: -true
```

addedOutput schema / properties

Added value: +{
+  "result": {
+    "allOf": [
+      {
+        "properties": {
+          "meta": {
+            "additionalProperties": {},
+            "properties": {},
+            "type": "object"
+          },
+          "ok": {
+            "enum": [
+              true
+            ],
+            "type": "boolean"
+          }
+        },
+        "required": [
+          "ok",
+          "meta"
+        ],
+        "type": "object"
+      },
+      {
+        "properties": {
+          "data": {
+            "additionalProperties": false,
+            "properties": {
+              "not_found": {
+                "items": {
+                  "type": "string"
+                },
+                "type": "array"
+              },
+              "snippets": {
+                "items": {
+                  "additionalProperties": false,
+                  "properties": {
+                    "message_id": {
+                      "type": "string"
+                    },
+                    "preview": {
+                      "description": "Body preview snippet. May include mark tags.",
+                      "type": [
+                        "string",
+                        "null"
+                      ]
+                    },
+                    "subject": {
+                      "description": "Subject snippet. May include mark tags.",
+                      "type": [
+                        "string",
+                        "null"
+                      ]
+                    }
+                  },
+                  "required": [
+                    "message_id",
+                    "subject",
+                    "preview"
+                  ],
+                  "type": "object"
+                },
+                "type": "array"
+              },
+              "sync_state": {
+                "type": [
+                  "string",
+                  "null"
+                ]
+              }
+            },
+            "required": [
+              "snippets",
+              "not_found",
+              "sync_state"
+            ],
+            "type": "object"
+          },
+          "meta": {
+            "additionalProperties": false,
+            "properties": {
+              "request_id": {
+                "example": "req_clxxxxxxxxxxxxxxxxxxxxxxxxx",
+                "type": "string"
+              }
+            },
+            "required": [
+              "request_id"
+            ],
+            "type": "object"
+          }
+        },
+        "required": [
+          "data"
+        ],
+        "type": "object"
+      }
+    ],
+    "unevaluatedProperties": {
+      "not": {}
+    },
+    "x-fastmcp-top-level-schema": "MailboxSearchSnippetsResultResponse"
+  }
+}

addedOutput schema / required
```
Added value: +[
+  "result"
+]
```

First observedv1.0.0Jul 13, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Annotations already declare the operation read-only, idempotent, and non-destructive. The description adds a distinct behavioral disclosure beyond those annotations: snippets may not be sufficient for content-specific claims, so agents must read the underlying messages first. This is valuable context that the schema and annotations do not provide.

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 with no wasted words. The main purpose is front-loaded, filters are compactly grouped, and the critical read-before-claim caveat is placed at the end. It avoids repeating schema details and is easy for an agent to parse.

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 21-parameter tool, the description is sufficient because the schema documents every parameter and the output schema covers the return shape. The annotations fully cover the safety profile, and the description adds the one operational caveat an agent needs: read full messages before making content-specific claims. Nothing critical 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?

All 21 parameters already have description coverage in the input schema, so the description does not need to explain individual fields. It adds a useful thematic grouping of filters, but no additional syntax or semantic meaning beyond what the schema provides. 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 opens with a specific action and resource: 'search message snippets by query text.' This clearly identifies the tool as a snippet search rather than a full-message retrieval or listing tool, and the closing instruction to read full messages reinforces that it returns snippets/IDs. It is unambiguous and differentiates from siblings like mailbox_get_message and mailbox_list_messages.

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 states the primary use case and enumerates the main narrowing dimensions: folder, keyword, dates, sender/recipient, unread state, and attachments. It also gives a clear operational caution: use returned message IDs with a read tool before making content-specific claims. However, it does not explicitly name the read tool or state when not to use this tool versus a sibling, so the guidance is strong but not fully explicit.

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