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

Annotations only cover the safety profile (not read-only, idempotent, non-destructive). The description adds genuinely non-obvious behavior: the 90-day snooze ceiling, that assigning notifies the teammate, that no message is sent and no platform state changes, that at least one field must be supplied, and that the call is refused on non-Pro/Business plans or before Inbox availability.

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?

Front-loaded with the operations and side-effect caveat, and each sentence carries information. The final sentence restates the same four operations already enumerated in sentence one, which is mild redundancy but also serves as an explicit usage trigger.

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?

With an output schema present, the description need not explain returns, and it covers the remaining agent-critical gaps: plan gating, refusal behavior, no outbound message, teammate notification, snooze bounds, and the minimum-field requirement. An agent can call this correctly without further inference.

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 the baseline is 3, but the description contributes constraints the schema does not state: the 90-day maximum for snoozedUntil and the 'send at least one field' requirement beyond the single required conversationId. It does not add format or interaction detail (e.g., that status clears a snooze) beyond what the schema already says.

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 specific verb (change how the workspace handles) plus the resource (one Inbox conversation) and enumerates the four concrete operations. It is immediately distinguishable from get_conversation, list_conversations, and reply_to_conversation, especially via the explicit note that nothing is sent to the other person.

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?

The closing sentence gives a clear when-to-use trigger ('Use this when the user wants to mark a conversation read or unread, archive or reopen it, snooze it, or assign it to a teammate') and the 'nothing is sent' clause implicitly excludes reply_to_conversation. It never names an alternative sibling tool explicitly, so it stops short of a full when/when-not/alternative treatment.

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