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

With no annotations, the description carries the full burden and covers it thoroughly: grading thresholds, score range, snapshot nature, informational-only status, payment requirements, and the by-design neutral band. It also discloses the per-timeframe breakdown, so an agent knows exactly what to expect in the response.

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 long but densely packed with necessary information. It front-loads the core purpose, then grading, then payment, then sibling contrast. Every sentence adds functional value, though it could be slightly more condensed without losing essential details.

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 being a paid tool with no output schema, the description fully covers return values (zone, score, per-timeframe breakdown), grading logic, payment flow, and the difference from pitch. There is nothing an agent needs to know to call it correctly that is omitted.

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 coverage is 100% (symbol with description). The description adds value beyond the schema: it specifies the covered universe (S&P500 + major indexes), gives examples including indices with caret, and explains how the symbol maps to the output. This enriches meaning without redundancy.

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 ('Return') with a clear resource ('bottom/top verdict') and scope ('one US stock or index/ETF'), and explicitly contrasts with sibling pitch to differentiate. Includes concrete examples and universe coverage, so an agent knows exactly what this tool does and what it does not.

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?

Provides clear guidance: use this for any covered symbol versus the free pitch which is showcase-only. Mentions payment and retry on 402, implying when to invoke. However, it does not explicitly contrast with scan_bottoms/scan_tops (which likely scan multiple symbols), but the single-symbol mention makes that implicit.

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