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

Goes well beyond the readOnlyHint/openWorldHint annotations by disclosing the billing model ($0.002 USDC per successful call), the payment rails (x402 on Base, Solana or Arc), and that failed calls are free — material facts for an agent deciding whether to call. It also scopes the behavior (listing only, no execution) and names what each result row contains, which the annotations cannot convey.

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 short sentences with zero filler: purpose first, scope exclusion second, cost and payment mechanics third. The most decision-relevant constraint (it does not return product data) is front-loaded ahead of pricing details.

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 two-parameter read tool with an output schema already defined, the description covers everything an agent needs: what it searches, what it returns at a high level, what it will not do, and the exact cost and charging condition. The disambiguation against a very large set of product-specific sibling scrapers is handled explicitly.

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%, with both `q` (2–60 chars) and `limit` (1–20, default 5) documented in the schema itself, so the baseline of 3 applies. The description adds no extra meaning about the keyword semantics or the practical effect of `limit`, and does not flag that `limit` is typed as a string in 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?

States a specific verb and resource ("Searches the public Apify Store for scraper actors by keyword") and enumerates the returned fields (name, author, short description, 30-day user count). It explicitly carves itself out from the product-scraping siblings by saying it "Lists actors only; it does not run them or return product data."

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?

Gives clear context for when this tool is the right pick — catalogue/keyword discovery rather than data retrieval — via the explicit negative "does not run them or return product data." It stops short of naming a specific alternative sibling to use instead when the agent actually wants product data, leaving that routing to inference.

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