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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the composition of the read (which sub-metrics it returns) and the 'End-of-day' update cadence, which tells the agent the data is not intraday.

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?

A single dense clause enumerating the read's components, followed by a positioning line and a cadence tag. It is front-loaded and every sentence carries information, though the opening branding phrase ('Closelooknet's factor-regime read') is slightly redundant with the title.

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 and no parameters, the description carries the burden of conveying what comes back, and it does so by naming the ratio, trend, percentile, and rate-of-change dimensions. The 'End-of-day' note covers freshness. It is complete enough to call the tool confidently, with only minor ambiguity about the exact response shape.

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 takes zero parameters, so there is nothing for the description to disambiguate. Baseline is 4 for a no-parameter tool; the description correctly signals that this is a fixed, argument-free read.

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?

States a specific verb and resource (factor-regime read) and names the exact instruments (SPMO vs SPLV), the comparison basis (50-day trend), and the derived metrics (3-year percentile, 20/60-day ROC). This distinguishes it clearly from siblings like get_macro_regime and get_ratio_pair, which cover different regime concepts.

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?

The line 'the fastest single read on risk appetite under the index surface' gives an implied usage context, but there is no explicit when-to-use/when-not-to-use guidance and no named alternative (e.g., get_macro_regime for broader regime, get_ratio_pair for arbitrary pairs). The agent must infer the routing decision.

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