unsubscribe_from_email

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

With no annotations, the description carries the full burden. It discloses the mechanism (List-Unsubscribe), the fallback to mailto, and the return value (method used), which is meaningful behavioral context. It does not cover edge cases like what happens when no header exists, but for a relatively simple tool, it is transparent enough.

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 three concise sentences, each adding meaningful details: the core action, the comparison to Gmail, the fallback mechanism, and the return value. It is front-loaded and free of fluff.

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 tool is simple with three parameters and no output schema. The description covers the main behavior, fallback, and return value, making it sufficient for invocation. It doesn't mention error handling when no List-Unsubscribe header is present, but that is a minor gap given the tool's simplicity.

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 baseline is 3. The description adds no additional parameter-level context beyond the schema's own descriptions (e.g., account and message_id are not explained further). It neither enhances nor detracts from the schema.

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's purpose: 'Unsubscribe from a mailing list' by invoking the List-Unsubscribe header. It also distinguishes itself from siblings like block_sender by specifying the exact mechanism (RFC 2369/8058) and referencing Gmail's native button, making it unambiguous.

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 clear context by comparing to Gmail's 'Unsubscribe' button, indicating when this tool is appropriate. However, it does not explicitly mention alternatives or exclusions (e.g., when to use block_sender instead), so it falls short of a perfect score.

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