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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds genuinely useful traits beyond annotations: the pay-per-prompt cost ($0.04 USDC x402) and the fact it 'buys the tools above and writes a brief.' The 'writing a brief' phrasing does not contradict readOnlyHint since it refers to producing output text, not mutating external state.

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?

One compact sentence with the cost trait front-loaded and the mechanics (buys tools, writes brief) immediately after. Minimal waste. The only slight inefficiency is the parenthetical 'with Claude when enabled' adding conditional nuance, but it is short and informative.

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 single-parameter agent tool with a full output schema and safety annotations, the description covers the essentials: what it does, what it costs, and its scope. It could mention when the Claude-assisted brief is produced or clarify what the returned brief contains, but nothing critical is missing for invoking it.

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 the single 'prompt' parameter is already fully documented in the schema ('Your question about Argus launches / Arc markets'). The description adds no param-specific detail beyond restating the scope, so the baseline 3 applies.

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 behavior: a Fuci agent answers your question by buying the tools above and writing a brief. It names the price and the scoping from the schema ('question about Argus launches / Arc markets'). It is clear but stops short of crisply differentiating itself from the sibling tools (e.g., market_search), which an agent could confuse it with.

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 never says when to invoke this agent versus directly using the sibling tools (market_search, argus_launches, fucus_oracle). Since this is a PAID tool ($0.04) that delegates to other tools, an agent needs explicit routing guidance (e.g., 'use for complex multi-step questions; use market_search for simple lookups'). That guidance is entirely absent.

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