Email Mark Read

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

Annotations already flag readOnly=false and destructive=false, so the description need not repeat that. 'set \Seen' adds the useful detail that this is a flag mutation rather than a move or delete. It does not disclose whether marking an already-read message has any side effects or what a successful call returns, but the output schema presumably covers the latter.

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 six words and contains no filler; the action and mechanism are front-loaded. It earns a high score for efficiency, even though more usage detail could have been included.

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 simple two-parameter mutation with full schema coverage and existing output schema, the description gives enough to invoke the tool correctly. The main gap is the lack of explicit routing to email_mark_unread or any caution about when not to mark a message read, so it is not fully contextualized.

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?

All parameters (folder and message_id) are fully documented in the JSON schema, including defaults and scope, so the description doesn't need to repeat them. It adds no extra parameter semantics, which is acceptable but not additive.

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?

States a concrete action and target: 'Mark a message as read' with the IMAP flag mechanism. This is specific enough to distinguish from email_mark_unread by the seen/unseen state, though it does not explicitly name that sibling.

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 no guidance about when to choose this over email_mark_unread, no prerequisites, and no mention of folder/UID validity (left to schema). The only context is the action itself; decision-making is left to inference.

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