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

Annotations already mark readOnlyHint=true and destructiveHint=false. The description adds valuable context: data freshness ('nightly', 'End-of-day'), methodology ('recency-weighted regression on log-closes'), and coverage (~330 stocks). This goes beyond what annotations convey, though it doesn't disclose every edge case.

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 dense yet efficient. The first sentence is a compact definition, the seven views are listed, and the closing sentence provides source context. No filler words; every clause contributes.

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 carries a heavier burden. It explains the ranking concept and all view options, but doesn't explicitly state the response format (e.g., whether it returns ticker and score). For a simple ranking tool, it's nearly complete, but a brief mention of output shape would seal the gap.

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 covers both parameters with descriptions and an enum for view. The description enhances the enum by mapping each value to human-readable phrases with timeframes: 'rising fastest (21d)', 'this week’s biggest moves (5d)', etc., adding meaning not present in the schema itself.

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 identifies the tool as returning the nightly Directional Flow ranking, with specific methodology (recency-weighted regression on log-closes) and enumerates all seven ranking views. This distinguishes it from sibling tools like get_signal_scores or get_factor_regime.

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 description provides clear context: it is the nightly, end-of-day ranking tool, and it mirrors a known web page. It implies when to use it (for trend-quality rankings) without explicitly naming alternatives or exclusion scenarios, so it stops short of a 5.

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