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

Annotations declare readOnlyHint=true, so the read-only nature is known. The description adds useful context: weekly update frequency, composition of the score (20-day OFR FSI persistence ratio x inverted-curve weight), and return fields. No contradictions with 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 front-loaded with the core purpose, but the first sentence is dense with parenthetical detail (formula components), which slightly hampers readability. Each element serves a purpose, but it could be more streamlined. Overall, it is reasonably concise for the information provided.

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 output schema, the description compensates by listing return fields (persistence_score, fsi_20d_avg, yield_slope). It covers frequency, scope, usage intent, and history option (via schema). Minor gap: no explanation of what each field represents, but names are self-explanatory. Adequate for a single-param 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?

Schema description coverage is 100% for the single optional 'days' parameter, including range and Gold tier implications. The description adds no extra parameter information, so baseline of 3 is appropriate since the schema handles parameter semantics thoroughly.

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 a specific action: 'Returns a 0-100 financial-stress persistence score' with detailed composition. It distinguishes itself from equity-only VIX, noting it spans five asset classes, making it unique among siblings.

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?

Explicitly provides when to call: 'Call when the user asks about transient vs. persistent market stress, regime shifts, credit or funding dislocations, or yield-curve inversion, or when timing hedge triggers and risk-on/risk-off posture changes.' It lacks explicit exclusions or alternative tool names, but the context is clear.

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