mark_email_read

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

Annotations already indicate this is mutable (readOnlyHint false) and idempotent (idempotentHint true). The description adds no additional behavioral quirks beyond the core operation. It is consistent with annotations, but does not expand on side effects or permissions.

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, each earning its place: purpose, when to use, when not to use. Front-loaded with core action, no fluff.

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 tool with 2 parameters and no output schema, the description covers the essential aspects: what it does, when to use, and alternatives. No gaps remain.

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?

Input schema has 100% coverage with descriptions for both parameters (emailId, read). The description does not add parameter-level details beyond what is in the schema. According to guidelines, baseline is 3 when schema coverage is high.

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 clearly states the action (mark) and resource (one email's read state). It explicitly distinguishes itself from sibling tool 'bulk_mark_read' by emphasizing 'one email' and contrasting with bulk operations.

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 explicit guidance on when to use (after selecting a specific email, to clear unread or mark unread for later) and when not to use (bulk mailbox triage), with a direct alternative (bulk_mark_read). This is exemplary.

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