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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is known. However, the description adds no behavioral context beyond the schema fields—it does not disclose return format, error behavior, or any subtleties. It essentially restates what the tool name implies.

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, short sentence with no wasted words. It is front-loaded with the key concept. However, it is under-specified, which slightly reduces the score from a perfect 5.

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?

The tool is simple with only two parameters and an output schema, so the description does not need to explain return values. But it fails to mention the required 'chain' parameter, which chains are supported, or how this differs from related tools. The existing annotations and output schema mitigate some gaps, but the description remains incomplete for reliable invocation.

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 0%, so the description must explain parameters, but it only mentions 'by txid' and completely ignores the required 'chain' parameter. The schema examples hint at possible chains (bitcoin, ethereum) but no description is given, leaving the agent to infer meaning from examples alone.

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 'Transaction details by txid.' clearly identifies the resource (transaction) and the lookup key (txid), distinguishing it from siblings like 'block' or 'node'. However, it lacks an explicit verb like 'get' or 'retrieve', and it omits the 'chain' parameter, which is necessary context.

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 such as 'block' or 'address'. It does not mention any prerequisites, exclusions, or scenarios where the tool is appropriate. This leaves the agent without direction for tool selection.

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