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

Annotations already mark the tool as read-only and open-world, and the description builds on that by disclosing the exact cost ('Paid $0.01 USDC exact on Base'), the payTo address, and that it uses a public API. This adds meaningful operational context beyond the annotations without contradicting them.

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 nearly every clause carries useful information, including payment, required mode, parameter options, and scope. It is only slightly dense because payment details appear before the core purpose, but the overall size is appropriate and there is no filler.

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?

For an agent deciding whether and how to invoke this tool, the description covers the key requirements: query mode, optional parameters, valid sort values, result count limits, scope, and cost. The main gap is that there is no output schema and the description does not indicate what the response object will look like, though that may be inferable from the Stack Exchange API context.

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?

Although the schema already documents all five parameters, the description enriches them with actionable semantics: q is conditionally required, id is an alternative, sort has explicit allowed values, hits is bounded to 1..8 with a default, and tagged is limited to three comma-separated tags. That is substantial value beyond the raw 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 a specific action and resource: 'Stack Overflow Q&A search via public Stack Exchange API.' It also distinguishes itself from similar tools with 'Stack Overflow only' and 'Complements /hn and /arxiv,' so an agent can tell when this tool, rather than a sibling, is relevant.

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 gives practical invocation guidance: q is required unless id is used, sort and hits have valid ranges, and tagged is limited. The phrase 'Stack Overflow only' provides a boundary, and naming /hn and /arxiv as complements points toward alternatives. However, it does not explicitly state when not to use this tool beyond that boundary.

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