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

Annotations already establish readOnly/idempotent/non-destructive. The description adds useful auth context ('No API key needed', guest-callable), but its pricing line 'Price 0.01 USDC/query (max 20 queries/session)' directly confuses a tool that is advertised as free, and 'no key, no payment' is stated twice. The net behavioral signal is muddled rather than clarified.

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 text is bloated promotional copy with an emoji, repeated 'free/no key/no payment' claims, and listing-specific sample questions. The CTA is front-loaded, but several sentences are redundant and the useful information is buried in marketing noise.

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?

There is no output schema, so the description carries the burden of explaining what a preview returns — and it does not. It says nothing about the shape or scope of the previewed data (the schema's own 'public metadata only' note is the sole hint), leaving an agent unable to predict the response.

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 description coverage is 100%, so both slug and question are already documented in the schema. The sample questions loosely hint at the question parameter's content, but the description adds no syntax, format, or constraint detail beyond what the schema provides.

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 conveys that this is a free, guest-callable preview of a data listing, and 'FREE preview — no key, no payment' states the purpose. However, it is heavily contaminated with listing-specific promotional content ('applenewswatch', sample questions) that makes it harder to read the generic tool's purpose, and it never clearly states what the preview actually returns.

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?

It urges 'call this now' and 'Try one of the sample questions now' but gives no decision criteria relative to siblings like data_session_query or data_session_open. It implies this is the free first step but never explicitly says when to graduate to the paid query tools.

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