Imessage Links

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

Annotations already declare readOnlyHint=true, so the agent knows this is a safe read operation. The description adds minimal behavioral context beyond that—it doesn't mention what the output looks like, whether it returns deduplicated links, or any limitations (e.g., only searches the default 30 days unless specified). With annotations covering the safety profile, a 3 is appropriate because the description adds some value but not rich behavioral context.

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 a single, concise sentence that front-loads the core purpose. It's efficient and easy to parse. It could add a bit more context about output or usage, but for its length it's well-structured.

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 the tool's simplicity (2 optional params, no nested objects, output schema exists), the description is mostly adequate. However, it doesn't mention what the output looks like (though output schema exists), nor does it clarify whether the tool searches only the default 30 days or if days_back is required for longer searches. The sibling tools suggest a broader iMessage context, and the description could benefit from a note about how this differs from imessage_search.

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 schema already documents both parameters (contact and days_back). The description doesn't add meaning beyond what the schema provides—it doesn't explain how contact filtering works or what format days_back should take. Baseline 3 is correct when schema does the heavy lifting.

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 function: finding URLs/links shared in iMessage conversations. It uses a specific verb ('Find') and resource ('URLs/links in iMessage conversations'). However, it doesn't explicitly differentiate from sibling tools like imessage_search, which could also be used to find content in iMessage conversations, so it loses a point for not distinguishing itself from that sibling.

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 implies usage context: use this when you need to find links shared in iMessage. It doesn't explicitly state when to use this tool versus alternatives like imessage_search, nor does it mention exclusions. The optional contact and days_back parameters imply filtering, but no explicit guidance is given about when to use this over a general search.

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