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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds the return shape and data provenance (CoinGecko), which is genuinely useful, but leaves out rate limits or auth needs, so not a full 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?

Densely front-loaded with purpose, usage, exclusions, and returns in a compact form. Slightly list-heavy but every section earns its place.

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, but the description enumerates the return object keys, and annotations cover safety. Nothing critical for correct invocation is missing beyond parameter-level detail.

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 only 50% and the description says nothing about 'limit' or 'query'. The lone schema note '(currently informational)' is the only clue, and the description does not compensate for the undocumented limit parameter.

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?

Names specific verb+resource: CoinGecko trending coins, top markets, DeFi TVL and Fear & Greed. Clear it's an aggregate market-context tool, easily distinguishable from the on-chain siblings (btc/eth/xmr/zec/tron).

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?

Explicit 'When to use' cases (what's trending, tokens moving, risk appetite, TVL leaders) and a 'Do not use' exclusion that routes to on-chain settlement tools and price charts. No inference needed to select it.

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