read_holding_registers

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

With no annotations provided, the description carries the burden. It correctly states the tool is read-only and describes the return format (start address, count, unit id, list of address->value pairs). However, it does not disclose potential error conditions, timeouts, or concurrency behavior, leaving gaps in transparency.

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 concise (2 sentences) and front-loads the key purpose with the function code. It efficiently covers the operation, data type, and return structure without unnecessary detail.

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 output schema, the description adequately describes the return structure. It covers the essential aspects of the operation for a simple read tool. However, it omits details like the unit id source or defaults, which could be inferred but are not explicit.

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?

The input schema has 100% description coverage for both parameters (address and count) with clear ranges and defaults. The description adds no new information about parameter semantics beyond what the schema already provides.

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 tool reads holding registers using Modbus function code 0x03, specifying the data type (16-bit read/write values). It implicitly distinguishes from siblings like read_coils and read_input_registers by name and context, but could be more explicit about differentiation.

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 no guidance on when to use this tool versus alternatives or any prerequisites. It mentions 'Read-only' but does not specify when not to use it or any preconditions for the Modbus device.

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