analyze_deliverability

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

Discloses scope (most recent up to 100, single page) and lists metrics (delivered, bounced, complained, etc.) beyond what annotations provide. Annotations already indicate read-only and idempotent, no contradiction.

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?

Two sentences with no waste. Front-loaded with action and scope, immediately followed by 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 simplicity (one optional param, no output schema), the description fully covers purpose, scope, and use cases. No gaps.

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?

Only one parameter with full schema coverage (100%). Description does not add additional meaning beyond schema, baseline score of 3 is appropriate.

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?

Description clearly states it aggregates recent sent emails into deliverability metrics, with a specific verb ('Aggregate') and resource ('sent emails'), and distinguishes from siblings by focusing on email health analysis.

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 says 'Use to answer how is my email health? or to investigate a recent drop in delivery,' providing clear context. Missing explicit when-not-to-use or alternatives, but the purpose is well-defined.

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