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

Annotations already mark it as read-only and open-world, and the description usefully adds the returned signal shape, including that accuracy may be null. It does not describe refresh cadence or source behavior, but it adds meaningful context beyond the annotations without contradicting them.

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 compact and front-loaded: the first sentence defines the payload, and the second states when to call it. Every clause contributes useful information with no filler.

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?

With no input schema and no output schema, the description carries the return-value burden and does so by naming the main fields. It remains slightly incomplete about what action_hint and risk_level values mean, but it is sufficient for a no-parameter indicator tool.

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 there is no parameter semantics to explain and the baseline is 4. The description appropriately focuses on output fields instead of inventing input details.

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 identifies a compact BTC/EUR signal and lists the key returned fields (p_up, accuracy, action_hint, risk_level). It is distinguishable from broad market or probability tools by its BTC/EUR and machine-friendly framing, though it does not explicitly contrast with sibling signal 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 a clear usage cue: "Call this when you need a machine-friendly BTC indicator." However, it does not say when not to use it or name alternatives such as get_signal_cards, get_signal_stack, or get_probabilities, so the guidance is adequate but incomplete.

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