decode_register

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

With no annotations, the description carries the full behavioral burden, and it does so well: it discloses that the tool reads from the device unless a value is supplied and that it relies on the target's SVD for decoding. It also implies a non-destructive, read-only operation. It doesn't cover error cases or full return format, but 'named bit fields' gives a clear output expectation.

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, front-loaded sentence that packs the core purpose, conditional source behavior, and a practical use case without any filler. Every clause adds information, and the formatting is easily scannable.

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 three-parameter tool with no output schema, the description covers purpose, how the source is determined (device vs supplied value), and the expected output concept (named bit fields). It does not explicitly mention prerequisites like setting the SVD path, but that is implied by 'using the target's SVD' and is a reasonable gap for a specialized debugger tool.

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 baseline is 3. The schema already documents the 'value' parameter as a hex value used instead of reading the device, and both required parameters have examples. The tool description adds only a slight clarification of the conditional device-read behavior, not enough to raise the score.

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 opens with a specific verb and object: 'Decode a value into named bit fields using the target's SVD.' This clearly distinguishes it from siblings like read_register or read_peripheral, which fetch raw values rather than decode them. The behavior of reading from the device or using a supplied value is also clearly stated.

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 states a clear use case: 'useful for interpreting a number you already have,' which signals when an agent should use this tool with a supplied value. It also explains the alternative mode—reading from the device when no value is given—even though it doesn't explicitly name sibling tools. This gives adequate contextual guidance for selection.

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