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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), so the bar is lower; the description adds meaningful behavioral context by specifying end-of-day timing, engine-derived values, and the enumerated structural states (healthy leader / fragile / distribution / decoupling). It does not mention auth or rate limits, but for a read-only snapshot the disclosure is solid.

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 sentence, front-loaded with the resource and scope, followed by the returned fields and then the sibling pairing. Every clause carries information, though the long enumeration makes it heavier than strictly necessary.

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 correctly enumerates the returned fields and their sub-components, which is exactly what an agent needs to know what it will receive. For a single-required-param read tool this is close to complete; only return format details (e.g., structure of the trend changes) are left implicit.

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?

Only one parameter (ticker) and schema description coverage is 100%, so the schema already documents the format and example. The phrase 'one covered stock' mildly constrains the ticker to the covered universe, but adds little beyond the schema — baseline 3 is appropriate.

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?

Specific resource (one stock) plus the exact scope of what is returned: Directional Flow trend score with 5/21/63-day changes, up/down-day beta with structural state, and index memberships. It also names the sibling tools it complements (get_price_history, get_signal_scores), so an agent can distinguish it from adjacent tools without opening schemas.

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 frames the tool as the EOD snapshot to pair with get_price_history for bars and get_signal_scores for the quality panel, which tells an agent when this tool is the right one. No when-not-to-use or exclusion is stated, 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.