mark-as-unread

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

No annotations are provided, so the description must bear full transparency burden. It discloses the return ('a confirmation that the message was marked unread'), which is adequate for a simple state toggle. However, it does not mention idempotency or permissions, though these are implied by the tool's simplicity.

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 extremely concise with three sentences—no superfluous words. It fronts the usage guidance and return value, making it easy to scan.

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 single-parameter tool with an output schema, the description covers purpose, usage context, prerequisites (getting the id), and return value. It lacks only minor details like whether marking an already unread message is a no-op, but overall it is sufficiently 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 0%, so the description must compensate. It explains that the id parameter identifies the message and where to obtain it ('Get the id from search-messages or list-messages first'), but does not clarify the pattern or accepted formats, leaving some ambiguity.

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 explicitly states 'marking a single message (by id) as unread,' clearly defining the verb and resource. It distinguishes from sibling tools like 'batch-mark-as-unread' and 'mark-as-read' by specifying single vs. batch and unread vs. read.

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?

Provides explicit when-to-use ('marking a single message as unread') and when-not-to-use ('Do not use when: marking several at once... or marking read'), with direct references to alternative tools (batch-mark-as-unread, mark-as-read). Also instructs to obtain id from search-messages or list-messages.

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