hey_save_draft

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

Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=false, so the safety profile is partly covered. The description adds real value: it names the Drafts folder destination, discloses the return shape ({success, draftId?, error?}), and surfaces the key workflow limitation that sending isn't available via MCP.

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?

Front-loaded with the core action, then folder destination, optionality, return shape, and alternatives. Dense but every sentence carries distinct information; nothing is redundant with the schema.

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?

Despite no output schema, the description supplies the return shape, the folder behavior, the optionality semantics, and the critical workflow limitation that sending must happen outside MCP. An agent has everything needed to call it correctly.

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 coverage is 100%, so the params are already documented (baseline 3). The description adds rationale beyond the schema: recipients, subject, and body are all optional specifically so a partially-written draft can be saved, which explains the intended usage pattern.

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?

States a specific verb and resource ('Save a new draft email') plus scope ('without sending it'). It's immediately distinguishable from siblings like hey_edit_draft, hey_send_email, and hey_reply, which it names directly.

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?

Explicitly routes the agent: use hey_edit_draft to keep revising, hey_send_email/hey_reply to send immediately, and finish in the web/app UI since MCP can't send. When-to-use, when-not, and alternatives are all stated.

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