lookup_register

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

No annotations are provided, so the description carries the full burden. It implies a read-only operation ('Get full details') but doesn't disclose behavioral traits like error handling, performance characteristics, or output format. While it adds context about low-level firmware use, it lacks details on what happens if inputs are invalid or how results are structured.

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 efficiently structured in two sentences: the first states the purpose and key details, and the second provides usage guidelines. Every sentence adds value without redundancy, making it front-loaded and appropriately sized for the tool's complexity.

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 no annotations and no output schema, the description is moderately complete but has gaps. It covers purpose and usage well but lacks behavioral details like error cases or output structure. For a tool with 3 required parameters and no structured output, more context on what 'full details' includes would improve completeness, though it's adequate for basic use.

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 all three parameters (svd_file, peripheral, register) with clear descriptions. The description adds no additional parameter semantics beyond implying they are used to locate a specific register, which is already evident from the schema. Baseline 3 is appropriate as the 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 specific action ('Get full details') and resource ('for a specific register within a peripheral'), listing concrete attributes like address offset, size, access type, reset value, and bit-fields. It explicitly distinguishes from siblings by specifying exact register layout for low-level firmware code, unlike broader tools like list_peripherals or search_registers.

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 provides explicit guidance on when to use this tool ('when you need exact register layout for low-level firmware code'), implying alternatives like search_registers for broader queries or describe_field for bit-level details. It clearly defines the context without exclusions, helping the agent choose correctly among siblings.

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