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

With no annotations, the description carries the full burden and does substantial work: corpus size (36k+ endpoints), freshness (re-indexed every 6h), ranking signals (relevance, 30-day unique payers/calls, recency, price), dedup rule (max 2 per seller), dead-URL removal, and cost/payment rail ($0.005/call via x402 USDC). It omits rate limits and no-result behavior, which keeps it below a 5.

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?

Front-loaded with the decision question and purpose, followed by one dense but well-ordered sentence covering corpus, ranking, filters and price. Nearly every clause earns its place, though the run-on structure packs a lot of facts into a single sentence.

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 4-param tool with no output schema and no annotations, the description covers the return shape (method, price, networks, ready-to-send example call), cost, and freshness. The only real gap for correct invocation is the undocumented 'limit' parameter.

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 only 25% – just 'need' is documented – so the description must compensate. It does explain the two filter parameters (max_price, network) in a 'Filters:' clause, but leaves 'limit' entirely undefined and adds no format guidance for network values.

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: recommends/ranks x402 API endpoints from the Bazaar given a plain-language need. The opening question plus 'API recommender / discovery for agents' makes it unmistakably distinct from siblings like list_tools_and_prices or web_search.

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 framing question 'Which x402 API should I call?' and 'describe the need in plain words' give a clear trigger condition for calling it. It stops short of naming when not to use it or pointing to alternatives such as list_tools_and_prices, so it is clear context without explicit exclusions.

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