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

Annotations give readOnlyHint and openWorldHint, so the safety profile is already covered; the description contributes materially beyond that with the cost model ($0.002 USDC per successful call via x402 on Base/Solana/Arc, failed calls not charged) and the CC BY-SA licensing constraint. What it omits is behavioral detail like result ordering or pagination beyond the limit parameter, so not 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?

Two sentences, both load-bearing: the first defines the operation and output shape, the second carries the caveats (excerpts not full guides, licensing, pricing). The most decision-relevant information — what the tool searches — is front-loaded with zero preamble.

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?

The tool is simple (2 params, output schema present, safety covered by annotations) and the description covers the remaining agent-relevant unknowns: cost, billing behavior on failure, and the excerpt-vs-guide limitation. Minor gaps remain — no statement about result ordering or what an empty result set looks like — but nothing that would cause a wrong invocation.

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 both parameters (q with 2-100 char bounds, limit with 1-20 and default 5) are already fully documented in the input schema. The description adds no query syntax, operator support, or result-count semantics beyond what the schema provides, which is the expected baseline when the schema does the work.

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 states a specific verb and resource — 'Search English Wikivoyage travel guide articles' — and even enumerates the fields returned (title, snippet, word count, page id, URL, total hit count). That is enough for an agent to tell this apart from the hotel/booking siblings. It stops short of naming a specific alternative, so it lands at 4 rather than 5.

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?

'Snippets are search excerpts, not full guides' is a genuine usage constraint — it tells the agent to use this for discovery, not for retrieving full article content. However, there is no explicit when-to-use/when-not-to-use statement and no routing to siblings such as travel_rag_web_browser or travel_google_travel, so guidance is implied rather than stated.

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