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

The description adds behavioral context beyond the readOnlyHint annotation, notably explaining the stale flag (market closed) and clarifying that 'most active' is defined by dollar volume. It does not discuss pagination or permissions, but given the read-only annotation and simple nature of the tool, this is adequate and honest.

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 two sentences, front-loaded with the core concept, and every sentence provides necessary information. There is no redundancy or filler, making it an exemplary model of conciseness.

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?

The description covers the main behavior, the two modes, and the stale flag nuance. Since an output schema exists, return format details are not required. It does not mention limit constraints or ticker format, but those are already in the input schema. For a simple read-only snapshot tool, the description is sufficiently complete.

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%, so the baseline is 3. The description restates the ticker behavior already in the schema ('Omit for the most-active rows by dollar volume'), but adds a slight clarification of what the response will contain in each mode. The limit parameter is not mentioned in the description, but its schema description is clear. Thus the description adds marginal value beyond the schema.

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 states what the tool does: it returns a live scanner snapshot, with behavior varying based on whether a ticker is provided. It distinguishes from sibling tools by specifying the scanner context and the two operational modes (ticker row vs. most-active rows). The scope is unambiguous.

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 implies usage context: you use this tool to get scanner snapshot data, with or without a ticker. However, it does not explicitly state when to prefer this tool over alternatives like snacs_quote_get or snacs_bars_get, nor does it provide exclusions or alternative tool references. The guidance is present but implicit.

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