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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds genuinely useful behavior beyond that: it is a paid call ($0.004 via x402) with a specific endpoint, and it discloses the shape of the return (nearest level plus a full sorted list with distances in % and ATR). It does not cover failure modes for invalid or unsupported symbols, which keeps it from a 5.

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?

Two dense sentences with the identity, cost, and payload contents leading. The endpoint URL is arguably noise for an agent that invokes an MCP tool rather than HTTP, but it is brief and does not obscure the payload description.

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 well by enumerating every returned level type and the distance metrics. Combined with a single, fully documented parameter, an agent has enough to call and interpret this tool, with only the lack of sibling routing guidance as a 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 coverage is 100%: the single symbol parameter is documented with a pattern and the note 'US equity or ETF ticker'. The description adds no format or validation detail beyond the schema, so the baseline 3 applies.

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 names the resource (key price levels for a ticker) and enumerates the exact contents: nearest level above/below, 20-day and 52-week extremes, pivot/R1/S1, 50/200-day averages. It does not differentiate from siblings such as setup or trend, but an agent can still tell what data comes back.

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?

There is no explicit when-to-use or when-not-to-use guidance and no reference to any of the six sibling tools. The only usage-relevant facts are the price and endpoint, which describe access mechanics rather than when this tool should be selected over setup, trend, or regime.

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