Mark Email Forwarded

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

Adds important behavioral context about sourceFolder and potential silent no-ops, beyond the annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=true). No contradictions with annotations.

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?

Two sentences, front-loaded with purpose, with no wasted words. Every sentence adds value.

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?

Adequate for a simple marking tool with idempotentHint and output schema. Covers the key nuance of sourceFolder, though does not address invalid emailId behavior or return value.

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?

Adds significant meaning to forwarded (default true) and sourceFolder (detailed guidance on usage and pitfalls) beyond the schema, which has 33% coverage. The emailId is required but its identifier role is self-evident.

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 'Set or clear the $Forwarded keyword on an email' with a specific verb and resource, and distinguishes it from the sibling forward_email by noting it is the marker the forward tool writes.

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 guidance on when to pass sourceFolder, with detailed reasoning about IMAP UID scoping and warnings against using 'All Mail'. However, it does not offer explicit guidance on when to set vs clear the forwarded flag.

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