mark_emails_unreadMark up to 100 messages as unread across connected email accounts, helping you restore unread status for messages you need to revisit.
Mark 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.
v0.19.0Input 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: +100v0.16.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=true, and openWorldHint=false, so the safety profile is covered. The description adds nothing beyond that — no mention of batching limits, whether read state is per-message or per-thread, or what side effects (sync, unread counts) occur.
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?
A single short sentence, front-loaded with the action and resource — no filler whatsoever. It is arguably too terse rather than bloated, but there is no structural waste to penalize.
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?
This is a simple two-parameter mutation with annotations and an output schema, so much of the burden is shouldered by structured fields. Still, the description omits any note about what gets changed or the 100-message batch ceiling, leaving the agent to derive behavior entirely from schema and annotations.
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%, so both accountId (optional when one account is connected) and messageIds (1-100 IDs) are fully documented in the schema. The description's plural 'messages' is consistent with the batch array but contributes no additional meaning. Baseline 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 verb+resource (mark messages unread) is unambiguous, but the sentence is a near-verbatim restatement of the tool name and title, adding no scope detail. It also does nothing to distinguish this from the sibling mark_emails_read beyond the word 'unread'.
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 mark_emails_read, nor any note about context (e.g., after reading, for follow-up workflows). The agent must infer the entire selection rationale from the name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.