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

The description adds useful behavioral context beyond the readOnly/idempotent annotations: no API key is required, the call is free, and there is a session query cap. This is valuable because the annotations do not convey authentication or cost details. The 'Price 0.01 USDC/query' line is slightly ambiguous but is immediately tempered by 'FREE preview — no key, no payment.' No contradiction with annotations.

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 padded with promotional language and repetition: 'no key' appears twice, 'FREE preview — no key, no payment' is restated, and 'call this now' plus emojis add noise. The useful facts could fit in one tight sentence, so several sentences do not earn their place.

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?

This is a simple, read-only, zero-required-parameter tool with full schema coverage and safe annotations. The description covers authentication, cost, high-level limits, and sample usage. It does not describe the return shape, but no output schema exists and the input schema already notes 'public metadata only', so the key operational context is present.

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% and both parameters are optional with adequate schema descriptions. The description adds concrete sample questions that illustrate how the 'question' parameter might be used, giving an agent practical examples beyond the schema's dry 'echoed back' wording. This is modest but real added value.

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 tool's purpose is reasonably clear: it is a free preview of a data listing, explicitly tied to a specific listing and offering sample questions. The phrase 'FREE preview' plus the annotation title 'Preview Data Listing (Free)' identifies the operation, though the description is marketing-toned rather than a crisp 'previews a listing's public metadata' statement.

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 clearly marks this as the unauthenticated, free entry point ('No API key needed', 'FREE preview — no key, no payment') and hints at paid limits ('max 20 queries/session'). However, it never explicitly contrasts it with sibling tools like data_session_open or data_session_query, so an agent has to infer when to switch to paid functionality.

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