read_register

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description adds genuine beyond-annotation context: unsupported registers may time out, and the call has no mode-selecting side effect. It stops short of describing the returned value shape or timing expectations for valid registers.

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?

Two short sentences, the core capability and valid range front-loaded, followed by the failure mode and the no-side-effect caveat. No filler and nothing repeated from the schema or annotations.

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 one-parameter read tool with no output schema and annotations already carrying the safety profile, the description covers the actionable essentials: valid range, timeout risk on unsupported registers, and absence of mode switching. Only the interpretation of returned data is missing, which is minor.

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 0% and the schema only says "integer" with no bounds, so the description's 0..89 range is real added value. But it does not explain what individual registers map to (which hold diagnostics vs counter data) or what the returned value means, leaving the parameter only partly compensated.

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?

Specific verb + resource ("Read a protocol register") with a stated valid range (0..89) and a use domain (diagnostics or measurement/counter data). It does not explicitly distinguish itself from the closest sibling read_arbitrary, so it stops short of a 5.

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?

"for diagnostics or measurement/counter data" gives clear context for when this is the right call, and "this does not select a mode" is a useful negative hint. However it never names an alternative tool or states an explicit when-not-except-for-mode-selection condition, so usage remains implied rather than directed.

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