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

With no annotations, the description carries the full burden, and it does disclose the returned content (score, classification, 8-day trend), the data source (alternative.me), the real-time nature, and the cost ($0.02/call in USDC on eip155:8453). It omits auth/rate-limit/error behavior, but for a read-only sentiment fetch this is solid disclosure.

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 core purpose before the blending explanation and pricing. Efficient overall, though 'Sentiment blends volatility, momentum...' and 'a useful contrarian signal agents can cite with a number' lean slightly promotional rather than operational.

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?

No output schema and no annotations, yet the description explains what is returned, its source, and its cost — enough for an agent on a simple one-parameter read tool. It is near-complete, with only auth and error semantics left unstated.

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 100% so the 'days' trend window is already documented. The description's phrase 'plus the last 8 days for trend context' arguably conflicts with the variable 'days' parameter, providing mild confusion rather than added clarity, so baseline 3 is appropriate.

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 resource (Crypto Fear & Greed Index) and precisely what it returns: today's 0–100 sentiment score with its classification plus the last 8 days. No sibling tool produces sentiment, so it is inherently distinguishable from the calculators/crypto/data 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?

Explicitly gives a use condition — 'Use this when an agent needs to market sentiment, live from alternative.me' — which is clear context. It does not, however, name exclusions or any alternative tool to prefer in other cases, so it falls short of a full when/when-not rubric.

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