get_unsubscribe_link

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

Annotations already indicate readOnlyHint=true and destructiveHint=false, so the agent knows it is a safe read operation. The description adds behavioral detail (header-first then body fallback), which is useful. No contradictions, and it does not repeat what annotations already 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 very concise: only two sentences, no wasted words. The main action is front-loaded in the first sentence, and the second sentence adds important detail about the fallback behavior.

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 has a simple input (1 param) and no output schema. The description is complete for the input side, but it does not describe the return value format (e.g., string URL or null). An agent would benefit from knowing what to expect, so there is a gap in completeness.

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?

The schema provides full description for the single parameter message_id (100% coverage). The description does not add any additional parameter semantics beyond what the schema already states, so 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?

The description clearly states the tool extracts unsubscribe URLs from a message using two specific methods (header first, body fallback). The verb 'Extract' and resource 'unsubscribe URLs from a message' are specific, and it is distinct from all sibling tools which perform different email operations.

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 gives some guidance on the order of checking (header first, then body), which implies reliability. However, it does not explicitly state when to use this tool vs. alternatives. Since no sibling tool does something similar, it is still clear but could be more explicit about context.

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