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

The annotations declare readOnlyHint:true, but the description says 'Creates a DRAFT,' which is a write operation that persists a new resource. This directly contradicts the read-only annotation, and the description fails to reconcile or clarify the discrepancy.

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?

Three sentences carry unique, essential information: draft status, text formatting rules, and review advice. The most critical behavioral distinction (draft vs. send) is front-loaded, and no sentence is redundant or filler.

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?

The description covers the core behavior and text formatting, but there is no output schema and the description does not mention return values, error cases, or confirmation behavior. Given the tool creates a resource, this omission is a notable gap, though the main workflow is adequately explained.

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?

The input schema already covers all 6 parameters with 100% coverage, so the baseline is 3. The description adds meaningful semantics for the text parameter (blank line separates paragraphs, '#' starts a heading), which goes beyond the schema's 'Plain-text content.' This extra formatting detail justifies a score above baseline.

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 DRAFT' and explicitly contrasts it with send_campaign by noting 'Nothing is sent.' It also specifies the plain-text content format, making the tool's purpose unambiguous and distinguishable from siblings.

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 explicit next-step guidance: 'you then need to call send_campaign, or send it from the Mailcheer workspace.' It also advises to 'Always have the draft reviewed before sending,' giving clear when-to-use and post-call instructions.

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