unsubscribe_sender

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

Beyond destructiveHint=true, the description discloses the implementation via Proton Bridge SMTP, the conditional throw-and-return-link behavior, and the safety rationale for not auto-fetching URLs. This adds meaningful behavioral context that annotations alone do not provide.

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 sentences, front-loaded with the primary action, followed by edge case behavior and a prerequisite. No redundant or vague wording; every sentence earns its place.

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 tool with a simple schema and no output schema, the description covers the main behavior, edge case, and prerequisite. It does not specify the success return value, but this is a minor gap given the clarity of the action and the existence of related tools.

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%, with emailId described as from previous tool output and confirmed for confirmation. The description adds no additional parameter meaning beyond reinforcing that emailId comes from get_unsubscribe_info output, which is already in the schema. Baseline 3 applies.

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 action: executing the mailto: variant of a List-Unsubscribe header by sending a minimal unsubscribe email through Proton Bridge SMTP. It distinguishes from siblings like get_unsubscribe_info (which checks availability) and send_email (general send), and specifically mentions the https-only fallback behavior.

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 states when to use the tool (when header includes a mailto address) and when it throws (if only an https link), and instructs to call get_unsubscribe_info first. It also explains the server's policy of never auto-fetching URLs, guiding the agent to open https links manually instead.

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