mac_lookup

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

With no annotations, the description carries the behavioral burden. It explicitly discloses that the lookup is bundled and works without network, notes the registry size, and mentions extra behavior around multicast, locally-administered bits, and privacy MACs. It doesn't cover error handling or output shape, but the core behavioral traits are well stated.

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 two compact sentences with no filler. Main behavior is front-loaded, and the registry/offline constraint plus secondary capabilities are conveyed efficiently.

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 simple one-parameter read-only lookup, the description is nearly complete: input is fully documented in the schema, and the description explains offline behavior, registry scope, and what the tool can tell the agent. A note about the exact return format would be nice, but it is not essential here.

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 documents all accepted MAC formats with 100% coverage. The description adds no additional parameter-level meaning beyond the overall lookup purpose, so the 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?

Uses a specific verb ('Identify') with a clear resource ('vendor behind a MAC address'), then adds the registry source and secondary decoding behavior. This clearly differentiates it from the sibling DNS, IP, and subnet tools.

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 makes the intended use case obvious: look up a MAC address vendor, including offline capability. It doesn't name alternatives or exclusion criteria, but the sibling tools are unrelated and the context is unambiguous enough for an agent to decide 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.