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

The description discloses key behavior beyond what the annotations convey: the tool never returns corpus rows, returns public metadata only, defaults to the routed session's listing, and echoes back the optional question. These details materially inform an agent's expectations and are consistent with the readOnly/idempotent 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 compact and front-loaded: the 'no key needed / call now' trigger comes first, followed by what the user gets, what it excludes, parameter semantics, and the recommended next steps. Every clause adds value, and the use of arrows and emoji makes the flow easy to scan.

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?

Despite having no output schema, the description covers the returned fields, limits, authentication status, default slug behavior, optional question constraints, and the downstream purchase/query flow. The tool is simple, so this is fully sufficient for an agent to call it correctly.

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 the schema already fully documents both the slug and question parameters. The description repeats the default-slug behavior and the question-echo behavior but does not add substantial new parameter-level meaning 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 identifies the resource (a paid data listing), the action (free preview/taste), and the specific output (title, price, up to 3 sample questions, summary excerpt). It also distinguishes itself from paid sibling tools by emphasizing 'PUBLIC metadata only, never corpus rows' and 'No API key needed.'

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 explicitly states when to call ('No API key needed — call this now'), what to expect, and then routes the agent to the paid follow-up path: 'register → data_session_fund → data_session_query'. This makes the decision boundary between the free preview and the paid data access clear.

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