mark_emails_unreadMark messages as unread.
| Name | Required | Description | Default |
|---|---|---|---|
| accountId | No | Account to operate on. Optional when exactly one account is connected. | |
| messageIds | Yes | Messages to change, up to 100 IDs |
| Name | Required | Description | Default |
|---|---|---|---|
| data | Yes |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "additionalProperties": false,
+ "properties": {
+ "data": {
+ "additionalProperties": true,
+ "properties": {
+ "action": {
+ "type": "string"
+ },
+ "failed": {
+ "items": {
+ "additionalProperties": false,
+ "properties": {
+ "code": {
+ "type": "string"
+ },
+ "messageId": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "messageId",
+ "code"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "succeededIds": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "uncertainIds": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "action",
+ "succeededIds",
+ "failed",
+ "uncertainIds"
+ ],
+ "type": "object"
+ }
+ },
+ "required": [
+ "data"
+ ],
+ "type": "object"
+}Input schema / properties / accountId / anyOfPrevious value: -[
- {
- "minLength": 1,
- "type": "string"
- },
- {
- "type": "null"
- }
-]New value: +[
+ {
+ "maxLength": 512,
+ "minLength": 1,
+ "type": "string"
+ },
+ {
+ "type": "null"
+ }
+]Input schema / properties / messageIds / descriptionPrevious value: -"Messages to change, up to 100 distinct IDs"New value: +"Messages to change, up to 100 IDs"Input schema / properties / messageIds / items / maxLengthAdded value: +512Input schema / properties / messageIds / maxItemsAdded value: +100Input schema / $schemaPrevious value: -"https://json-schema.org/draft/2020-12/schema"New value: +"http://json-schema.org/draft-07/schema#"Input schema / properties / accountId / anyOfAdded value: +[
+ {
+ "minLength": 1,
+ "type": "string"
+ },
+ {
+ "type": "null"
+ }
+]Input schema / properties / accountId / descriptionAdded value: +"Account to operate on. Optional when exactly one account is connected."Input schema / properties / accountId / maxLengthRemoved value: -512Input schema / properties / accountId / minLengthRemoved value: -1Input schema / properties / accountId / typeRemoved value: -"string"Input schema / properties / messageIds / descriptionAdded value: +"Messages to change, up to 100 distinct IDs"Input schema / properties / messageIds / items / maxLengthRemoved value: -512Input schema / properties / messageIds / maxItemsRemoved value: -100Input schema / $schemaPrevious value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds nothing beyond that – no note on partial failure, invalid/stale message IDs, or what happens to folder/label state when a message is flipped to unread.
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?
One short, front-loaded sentence with zero waste, but it is undersized rather than concise – the single clause leaves no room for the operational context an agent needs. Appropriate sizing would be slightly longer given this is a mutating batch operation.
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?
An output schema exists, so return values needn't be explained, and annotations cover safety. Still, for a mutation tool that touches up to 100 messages, the description omits error behavior, account-resolution fallback, and any sibling contrast, leaving it inadequate for the tool's complexity.
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 100%: accountId's "optional when exactly one account is connected" and messageIds' "up to 100 IDs" are fully documented in the schema. The description contributes nothing extra, so the baseline of 3 applies.
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 gives a specific verb and resource ("Mark messages as unread"), so an agent knows the action unambiguously. However, it is essentially a restatement of the name/title and adds no scoping detail such as batch limits or the read/unread counterpart, so it clears the bar without distinguishing itself from the sibling set.
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?
There is no guidance on when to use this versus alternatives. The sibling mark_emails_read is the obvious inverse, and nothing steers the agent, nor is there any note about prerequisites like a connected account or whether the messages must currently be read.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.