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

With no annotations, the description carries the full burden and does well: it discloses pricing ($0.003 per call over x402 across Arc/Base/Solana/X1), latency (~1 second), the required x402 signing handshake, and the return shape ('each hit with its source, link, excerpt and date'). It does not cover failure modes if payment is rejected or any rate limits, which keeps it short of 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?

The content is dense and front-loads the source list, but the entire definition is a single run-on sentence cramming corpora, latency, result shape, parameters and billing together. The long source enumeration could be tightened since the schema already lists valid source values, so the structure does not fully earn its length.

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?

There is no output schema, so the description usefully specifies the return shape (source, link, excerpt, date) and fully explains the non-obvious payment workflow. It gives less coverage of error handling and what happens when payment fails, but for a four-parameter search tool it is largely sufficient.

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%, so all four parameters (q, limit, payment, sources) are already documented in the schema, which sets the baseline at 3. The description restates that q is required and sources/limit optional but adds no syntax or format detail beyond what the schema provides. It does echo the payment semantics, but that too is 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?

The description names a specific verb ('search') plus a concrete resource scope, enumerating the exact corpora searched (Wikipedia, Wikidata, arXiv, OpenAlex, Hacker News, Stack Overflow, etc.). This clearly separates it from siblings like web_read, page_extract, or find_open_datasets, which target single pages or dataset discovery rather than multi-source research aggregation.

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 states the essential call mechanics ('Pass q; optional sources and limit') and gives an explicit two-step payment procedure ('Call once without `payment` for the terms, sign them with your own wallet, call again with `payment`'). What's missing is any guidance on when this tool is preferable to alternatives such as web_read or arc_catalogue_search, so the agent must infer the boundary.

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