mark_email_read

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

No annotations are provided, so the description carries the burden. It discloses return behavior (success confirmation, error if email ID does not exist) and mentions reversibility, but does not cover permissions, idempotency, or any side effects beyond the state change. The disclosure is adequate but not extensive.

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?

Three sentences deliver purpose, usage, and behavioral outcomes without redundancy. The description is front-loaded with the main action and each subsequent sentence adds essential information (clear unread indicators, success/error behavior, reversal tool).

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 single-parameter mutation tool, the description covers purpose, usage, return behavior, and reversal. It lacks only minor details like permission requirements or idempotency, but these are not critical given the tool's simplicity and the schema's richness.

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%, and the parameter email_id is already described in the schema as 'The email ID to mark as read (e.g., from list_emails or search_emails)'. The description adds no parameter-specific semantics beyond what the schema provides, so baseline 3 is appropriate.

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 states a specific verb+resource ('Mark an email as read in Outlook') and clarifies the exact purpose ('clear unread indicators'). It distinguishes itself from siblings by explicitly naming mark_email_unread as the reverse action, making the tool's role unambiguous.

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 description provides clear usage context ('Use this to clear unread indicators on a message') and explicitly names the alternative/reverse tool ('Use mark_email_unread to reverse this action'). This qualifies as explicit alternatives and when-to-use guidance.

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