List links in a message

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

With no annotations, the description carries behavioral disclosure. It explicitly states URLs are never fetched/resolved/checked and explains the security rationale (attacker-controlled URLs). Also discloses the prerequisite of a published body index.

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?

Three concise sentences: the first states the tool's output, the second explains the crucial security behavior, and the third gives the prerequisite. No fluff or repetition.

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?

Given its simplicity (one parameter, no output schema), the description is sufficient: it tells what, why, and under what conditions. The reference to get_email_body provides useful analogy. No significant gaps.

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 input schema already fully describes the 'key' parameter, including its opaque nature and stability. The description adds no additional parameter semantics beyond the prerequisite, which relates to the message rather than the key. Baseline of 3 is appropriate given high schema coverage.

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 clearly that the tool returns http/https URLs found in a message as text. This differentiates it from sibling tools like get_email_body and get_email_attachment. The purpose is immediately understandable.

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?

Explains that a published body index is required, mirroring get_email_body, which gives context on prerequisites. Does not explicitly name alternative tools, but the security warning clarifies why links are not fetched. Sufficient guidance for an agent deciding when to call it.

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