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

With no annotations, the description carries the behavioral burden. It is transparent that this is a read-only market snapshot and lists the derived regime calculation. It doesn't mention update frequency or exact formatting, but there is no mutation or hidden side-effect suggested.

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 concise sentences: the first front-loads the returned data in a readable list, and the second gives the intended use. No filler words or redundant schema repetition.

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 no-parameter, read-only overview tool, the description fully covers the returned values and the reason to call it. Without an output schema, this enumeration is sufficient for an agent to know what to expect and use it appropriately.

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 tool has zero parameters, so the 0-param baseline of 4 applies. The description makes clear no selection is needed: it returns the market context as a whole. No parameter-level explanation is required.

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 specifies exactly what the tool provides: total crypto market cap with 24-hour change, Bitcoin dominance, BTC 7/30-day moves, distance from peak, and a derived regime. It frames this as the market-level read and explicitly contrasts with putting a single coin in context, distinguishing it clearly from sibling coin-specific tools.

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?

It gives an explicit use case: 'Use it to put a single coin's move in context.' This clearly signals when to call it. It doesn't name exclusion cases or alternative tools, but the context is strong enough for an agent to select it over coin-specific siblings.

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