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

Annotations already declare this is read-only, idempotent, non-destructive, and closed-world. The description adds useful context beyond them: the score range, the four-year comparison window, the component factors, and the fact that the result includes 'its parts.' It does not discuss auth or rate limits, but those are lower-priority given the annotations.

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 compact sentences with the core definition front-loaded, followed by a clarifying exclusion. It contains no redundant or filler language.

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 read-only tool with one optional parameter, rich annotations, and no output schema, the description is largely complete: it explains the metric, score range, comparison window, factors, and exclusions. It could be slightly more explicit about what the returned 'parts' look like or how to interpret zone boundaries, but nothing essential to invoking the tool appears missing.

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 100%, and the single optional parameter 'historico' is fully documented in the schema as requesting daily scores when set to 1. The description adds no parameter-specific meaning beyond the schema, 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 defines the tool as producing a 1–100 Bitcoin zone score comparing Bitcoin to its own last four years across trend, momentum, funding, fear and greed. It does not explicitly name sibling tools such as fear_greed or funding, so sibling differentiation is only implicit through the composite metric framing.

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 implied usage by stating the score measures how high or low Bitcoin is relative to its own history and explicitly says it is 'not cheap/expensive and not a signal.' However, it does not state when to use this tool versus alternatives or provide explicit exclusions beyond those two negative clarifications.

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