unsubscribe

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

With no annotations, the description carries the full burden and does so: it discloses the escalation path (RFC 8058 HTTPS POST first, then mailto from the user's account), the terminal fallback (return the web link for the user to open), and the real-world side effect of confirming the address is live. Minor unstated items like error behavior are not enough to lower this.

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?

Four sentences, front-loaded with purpose, then mechanism, then fallback, then the safety exclusion. No filler and every clause carries operational information.

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?

For a two-parameter, no-output-schema tool that triggers external network actions, this covers purpose, mechanism order, fallback, input shape, and a safety precondition. The only gap is that it does not say what is returned on the POST/mailto success paths, though it does describe the web-link return case.

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 adds that the ids are message ids tied to a message's List-Unsubscribe header and restates the 50-item cap and either/or rule, which reinforces the mutual exclusivity the schema already encodes. Small but genuine added meaning.

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 ('Unsubscribe from the mailing list a message came from') plus the exact mechanism (List-Unsubscribe header). It is clearly distinguishable from siblings like get_unsubscribe_info (inspection) or find_newsletters (discovery), which an agent could otherwise confuse with it.

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?

Gives an explicit negative rule ('Never use this on spam or phishing') with the reason (unsubscribing confirms the address is active), plus the preference order for mechanisms and the fallback when only a web link exists. That is when-to-use, when-not-to-use, and fallback behavior in one paragraph.

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