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

Adds substantial context beyond the readOnly/openWorld/idempotent annotations: verbatim-quoted supporting lines, the three verdict outcomes, that 404/503 sources are not charged, and the exact price plus payment rails (x402, USDC on five chains). That is precisely the billing and failure semantics an autonomous agent needs before spending money.

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?

Four tight sentences: trigger first, output contract second, failure/refund third, price last. No repetition of the annotation flags and 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?

An output schema exists, so return values needn't be spelled out, yet the description still surfaces the verdict vocabulary. Combined with the cost, payment networks and no-charge-on-unreadable-source rule, an agent has everything required to decide and call 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 coverage is 100% and the schema already documents both `claim` (10–300 chars, single statement) and `urls` (up to 3 https URLs, fallback behaviour). The description adds only the soft hint 'short claim' and nothing about URL format or the max-of-3 limit, so it does not meaningfully exceed 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?

States a specific verb and resource ('a short claim checked against sources') and immediately names the output contract (SUPPORTED / CONTRADICTED / INSUFFICIENT), which clearly separates it from siblings like get_extract, get_summarize or get_wiki that fetch or condense content rather than adjudicate a claim.

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?

Opens with an explicit trigger ('Use when an agent needs a short claim checked against sources') and the schema-described default behaviour (reads an SEC filing for ticker claims, else the Wikipedia articles named) tells the agent what happens when no URLs are supplied. It stops short of naming when NOT to use it or pointing at an alternative sibling.

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