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

Annotations already establish readOnlyHint=true and openWorldHint=true, but the description adds material context they cannot convey: paid articles cost 0.20 USDC via x402, and the call returns payment requirements instead of content in that case. This is genuinely useful behavioral disclosure, though it omits whether the payment-required response is an error or a normal result.

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?

Three tightly packed clauses that front-load the free case before the paid case. No filler, though the free/paid split as a single run-on sentence is slightly dense.

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 a one-parameter read tool with no output schema, the description covers both return paths (markdown text vs payment URL plus requirements) and the payment protocol. The remaining gap is the undefined articleId, which is the main thing an agent could get wrong.

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 0% and the description says nothing about articleId — no format, no source, no relationship to IDs returned by search. With one undocumented required parameter, the description fails to compensate for the schema gap.

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?

States a specific verb and resource ('returns the full markdown text' of an article) and splits behavior into FREE vs PAID cases, which is more informative than the title alone. It implicitly contrasts with the get_preview sibling by emphasizing 'full' content, but never names the alternative explicitly, so sibling differentiation is left to inference.

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 gives conditional context: free articles return text directly, paid articles return a payment URL that must be settled via HTTP 402. However, it never states when to call get_article versus get_preview or search, nor any exclusions, so usage guidance is implied rather than explicit.

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