createUnsubscribe

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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), and the description adds substantial behavioral context beyond that: it writes live data, unsubscribed addresses are excluded from newsletters and automated campaigns, transactional template emails still send, and there is no per-list opt-out. These are exactly the side effects an agent must know before calling.

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 bold-labeled sections (Use when, Required, See also) that let an agent scan in order. Every sentence adds routing or behavioral value with no 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?

With no output schema, the description still covers purpose, trigger condition, required input, side effects, and sibling alternatives. Nothing an agent needs to invoke it correctly is missing.

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 baseline is 3, but the description goes further by declaring 'email is the only meaningful input', which disambiguates the odd 'definitive' parameter that the schema says has no effect. That extra framing helps an agent avoid passing a meaningless value.

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 states a specific verb+resource ('Create a new unsubscribe record', 'Add email to unsubscribe list') and explicitly distinguishes itself from the update/delete siblings. An agent can identify the operation without opening the schema.

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?

It gives an explicit 'Use when' condition (programmatically adding an email address to the Unsubscribe List) and names the alternatives with their roles: updateUnsubscribe (modify existing) and deleteUnsubscribe (remove existing). Routing is unambiguous.

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