gb_lookup_register

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

With no annotations, the description carries the full burden. It discloses the nature of the operation ('look up' implies read-only) and details the returned data (address, aliases, access, models, bitfield layout, documentation text). It does not mention side effects or authentication, but for a lookup tool, this is sufficient and adds meaningful context beyond a bare action verb.

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 sentences with no redundancy. The first sentence states the purpose and input flexibility, the second lists the return contents. It is front-loaded with the primary action and includes all essential information without fluff.

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 tool with 2 parameters and no output schema, the description is sufficiently complete. It clarifies the input types and explicitly enumerates the return fields, so an agent knows what to expect. It does not describe the output format (e.g., JSON structure), but since no output schema is provided, this is a minor gap; the description still covers the essential usage details.

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 thoroughly. The description only restates that query can be an address, name, alias, or description, which is already in the schema. It adds no new syntax or format details beyond what the schema provides, meeting the baseline for full 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?

The description states a specific action ('Look up') on a specific resource ('hardware register') and enumerates the input forms (address, name, RGBDS alias, description). It clearly distinguishes from siblings like gb_list_registers (which lists registers) and gb_decode_register_value (which decodes values) by focusing on retrieving register details.

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 when to use the tool (when a register's details are needed) but does not explicitly mention alternatives or when not to use it. Sibling tool names provide context, but no direct guidance is given, so an agent must infer the appropriate choice.

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