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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false. The description adds meaningful context beyond annotations: cost is $0.001 USDC per successful call via x402 on Solana, and the same operation is available over HTTPS. That pricing and payment detail is valuable for an agent deciding whether and how to call it.

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 short and front-loaded: purpose first, then input format convention, an example, and finally pricing/endpoint details. Every sentence contributes useful information without excessive length.

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 simple one-parameter decode tool with no output schema, the description provides the essential input format, an example, and pricing/endpoint context. It could say more about invalid input handling or the max length, but it is largely complete for correct 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 compensate. It does so by specifying that letters are separated by one space, words by ' / ', and giving '... --- ... is SOS' as an example. It also notes the result is capitals, which clarifies output despite the lack of an output schema.

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 states a specific verb and resource: 'Decode international Morse.' It is clear what the tool does, but it does not explicitly distinguish itself from sibling tools such as morse_encode or morse_run.

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 explains Morse formatting and gives an example, but it does not say when to use this tool rather than alternatives like morse_encode or morse_timing. No when-to-use or when-not-to-use guidance is provided.

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