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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, but the description adds substantial non-obvious behaviors: the payment challenge on cold/unavailable reads, the free allowance for cached results, stale caching semantics, and the $0.003 USDC cost. This goes well beyond the annotations and is crucial for the agent to call correctly.

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 sentences, front-loaded with the core purpose, then payment behavior, then a caution. No filler words, every sentence carries essential information. The structure is efficient and scannable.

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 tool with one optional parameter and no output schema, the description covers everything an agent needs: what the recap contains, payment behavior, caching nuances, and the non-advice nature. The lack of an output schema is compensated by describing the content (ranked stories, links, window, freshness). No critical gaps.

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?

The input schema's description for x_payment already explains the signed payload and the challenge/retry flow (100% coverage). The tool description adds value by clarifying the free allowance and per-call cost, which are not in the schema, so it enriches the parameter's meaning beyond the schema. This is more than a baseline 3 but not a 5 because the core semantics are already well-documented.

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 ('Read') and a precise resource ('concise crypto market recap with ranked stories, source links where available, analysis window and freshness'). It clearly distinguishes this from a news tool (it's a recap, not live news) and includes the informational caveat 'not a recommendation,' making the tool's purpose unambiguous even among many siblings.

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 description gives clear context: it is for market context, not advice, and it explains when cached results are free vs when a payment challenge is issued. It does not explicitly mention alternatives or when-not-to-use relative to sibling tools, so it stops short of a 5, but the context is clear enough for an agent to decide usage.

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