create_reply_draft

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

No annotations are provided, so the description carries full burden. It mentions creating a draft and setting headers, but doesn't disclose behavioral traits such as whether this requires specific permissions, if drafts are saved automatically, error handling for invalid UIDs, or rate limits. The description is minimal and misses key operational details for a mutation tool.

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 concise with two sentences that directly state the tool's function and key behavior (setting headers). It's front-loaded with the main purpose, though it could be slightly more structured by explicitly separating purpose from technical details.

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 this is a mutation tool with no annotations and no output schema, the description is incomplete. It lacks information on what the tool returns (e.g., draft ID, success status), error conditions, or how it interacts with other tools like 'list_messages'. For a tool with 5 parameters and complex email threading behavior, more context is needed.

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 100%, so the schema fully documents all 5 parameters. The description adds no additional meaning beyond what's in the schema (e.g., it doesn't explain parameter interactions or provide examples). Baseline score of 3 is appropriate as the schema handles parameter documentation adequately.

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 ('Create a reply draft') and resource ('on an existing email thread'), with specific details about finding messages by UID and setting headers. It distinguishes from 'create_draft' by specifying this is for replies, though it doesn't explicitly contrast with other siblings like 'mark_message' or 'move_message'.

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 implies usage by mentioning it finds messages by UID and sets headers for threading, suggesting it's for replying to existing emails. However, it lacks explicit guidance on when to use this versus alternatives like 'create_draft' for new emails or other sibling tools, and doesn't mention prerequisites or exclusions.

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