create_thread_reply_draft

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

The description adds context beyond the destructiveHint annotation by explaining the automatic selection of the latest inbound message and the return of a draftId. However, it does not disclose potential side effects such as syncing to remote (though syncToRemote parameter implies this). With annotations only covering destructiveHint, the description provides moderate additional transparency but not comprehensive behavior.

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 three sentences, front-loaded with the core purpose, then usage guidance, alternative, and return value. Every sentence adds value with no fluff, making it highly concise and well-structured.

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 has 11 parameters and no output schema, the description covers key context: purpose, use case, alternative, selection behavior, and return value. It does not elaborate on all parameters or potential caveats, but with full schema coverage this is sufficient. Slightly incomplete due to lack of mention of sync behavior or error cases, but generally complete for the complexity.

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?

All parameters have descriptions in the schema (100% coverage), so the baseline is 3. The description aligns with the preferLatestInbound parameter by mentioning automatic selection of the latest inbound message, adding minimal extra meaning beyond schema. No significant parameter details are missing, but the description does not need to compensate.

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 creates a reply draft from a threadId, with the specific behavior of automatically selecting the latest inbound message. It distinguishes itself from create_reply_draft by noting the preference when an emailId is available, and from other draft tools by its thread-based focus.

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?

Explicit usage guidance is provided: 'Use when you have a threadId from get_threads or get_actionable_threads and want to stage a reply for review' and 'Prefer create_reply_draft when you already have a specific emailId.' This clearly states when to use the tool and when to use an alternative.

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