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

Annotations already set readOnlyHint=true, and the description aligns by describing a data-return operation. It adds meaningful behavior: daily aggregation of per-stock MFI/CMF composites, update frequency, and the nature of the trend output. It does not over-explain known read-only safety, but gives useful computational context beyond the annotation.

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 tight sentences plus 'Updates: daily.' Each sentence earns its place: the first explains output components, the second gives usage triggers. No redundant wording or over-specification.

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?

Despite having no output schema, the description enumerates all expected return elements (score, trend, per-sector means, leaderboards). The only parameter is well-covered by the schema, and the use cases are clear. The tool is simple enough that this fully equips an agent to select and invoke it correctly.

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 single optional parameter 'days' is fully documented in the input schema (coverage 100%), including its purpose (historical series), constraints (1-1825), and tier requirement. The main description adds nothing about parameters, so the baseline of 3 applies because the schema does the heavy lifting.

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 begins with a specific verb ('Returns') and clearly defines the resource (sector-rotation intensity score) with a concrete output structure (0-100 score, trend, per-sector means, top-5 leaderboards). It is highly specific and distinguishes from the large sibling set by focusing on sector money-flow rotation, a unique niche.

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?

Explicit 'Call when' clause lists three precise scenarios: asking about sector rotation, money flow/accumulation-distribution, and timing sector-ETF tilts/rebalances. This gives clear triggers, but does not mention when not to use or name alternative tools, so it misses the top criterion for a 5.

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