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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds a genuinely useful behavioral fact beyond them: a fixed cost of 2 credits per call, which matters for budgeting. It stops short of describing behavior for unknown or reserved company IDs, which keeps it below a 5.

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 purpose is front-loaded and the credit cost is a useful closer, but the opening redundantly restates the tool name twice ('Bluetooth Company Lookup: Bluetooth Company Lookup allows you to...'), and the second sentence largely repeats the first. Trimming the duplication would leave a tighter, equally informative definition.

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?

With one required parameter, full schema coverage, an output schema, and explicit read-only/open-world annotations, the description covers what an agent needs to select and invoke it correctly. The only omission is failure behavior for unknown identifiers, which is minor given the output schema carries the return shape.

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 coverage is 100% and the single parameter already documents decimal or 0x-prefixed hex formats with an Apple example. The description only restates 'Bluetooth SIG assigned company identifier', adding no syntax or edge-case meaning beyond the schema, 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?

States a specific verb and resource: 'identify Bluetooth device manufacturers by their Bluetooth SIG assigned company identifier.' That is narrow enough that an agent can distinguish it from adjacent lookups like USBVendorLookup, MACAddressLookup, or generic CompanyLookup without opening the schema.

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?

Usage is only implied through the enumerated targets (Bluetooth devices, beacons, accessories). There is no statement of when to prefer it, no prerequisites, and no mention of what to do when the identifier is unknown or belongs to an unregistered range.

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