Mark Email Answered

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

The description adds that the tool sets/clears the IMAP 'replied to' marker, which aligns with annotations (readOnlyHint=false, destructiveHint=false). It does not disclose additional behavioral traits beyond what annotations provide, such as permissions or error conditions. Annotations already indicate idempotent and non-destructive, so the description adds minimal extra context.

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 two sentences long, front-loaded with the core purpose, and contains no unnecessary words. Every sentence adds value: the first states the action, the second covers parameter defaults and usage guidance.

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?

Given the tool's medium complexity (4 parameters, 1 required) and the presence of an output schema, the description covers the main behavior and a key usage note. It lacks details on return values or error cases, but the output schema may handle that. It is adequate for a simple mutation tool.

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 50%. The description explains 'answered' (defaults to true) and 'sourceFolder' (when to pass), adding value beyond the schema. The 'emailId' and 'account_id' parameters are not explained in the description, but 'account_id' has a schema description. Overall, the description compensates partially for the coverage gap.

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 tool's purpose: to set or clear the 'Answered' flag (IMAP 'replied to' marker) on an email. It is a specific verb-resource combination that distinguishes it from sibling tools like mark_email_read or mark_forwarded.

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 context for usage, such as the default value for 'answered' (true) and when to pass 'sourceFolder' (when UID came from a folder other than INBOX). It does not explicitly state when not to use the tool or mention alternatives, but the guidance is sufficient for correct invocation.

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