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

With no annotations, the description carries the full burden of behavioral disclosure, but it only provides the minimal trait of being 'real-time'. It does not mention data sources, update frequency, error handling, or interpretation of the deviation value, leaving significant behavioral gaps.

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 two short sentences, front-loaded with the core purpose. Every word is meaningful, and there is no extraneous detail, making it highly concise and well-structured.

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?

Although the tool is simple with one parameter and no output schema, the description does not clarify what the peg deviation output looks like (e.g., percentage, basis points), nor does it mention any limitations or edge cases. Without an output schema, the description should provide more context about the return value, but it falls short.

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 schema fully describes the token_symbol parameter with examples. The description adds the phrase 'any stablecoin', which broadens the scope beyond the examples, but it does not add significant meaning beyond what the schema already provides, so the baseline of 3 is appropriate.

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 returns the real-time peg deviation for any stablecoin, which is a specific function. It distinguishes itself from the sibling tool peg_history by emphasizing 'real-time', and the mention of 'MiCA Art. 35' adds regulatory 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 does not provide guidance on when to use this tool versus alternatives like peg_history. It implies usage for current peg deviation but lacks explicit when-to-use/when-not-to-use or naming of alternative tools for other scenarios.

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