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

Annotations already declare readOnlyHint=true and openWorldHint=true, and the description adds useful behavioral context: no API key needed, ~10s caching, response fields, raw price values in quote currency, and known error modes (unknown symbol, geo-blocked exchange). No contradiction with annotations.

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?

The description is front-loaded with the core purpose, then organized into clearly labeled sections: Args, Returns, Examples, Errors, Alternatives. Every section earns its place and the length is justified by the need to convey defaults, formatting, and pitfalls for a multi-exchange tool.

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?

Given the tool has a full output schema and read-only annotations, the description is complete: it covers parameters, return structure, error handling, usage examples, and sibling differentiation. An agent has everything needed to invoke it correctly.

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 baseline is 3. The description goes well beyond the schema by providing concrete symbol examples ('BTC/USDT', 'BTC/KRW'), explaining that upbit/bithumb use KRW quotes, noting the geo-block fallback to okx, and mapping natural-language phrases to parameter values in examples.

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 opens with a specific verb and resource: 'Fetch the current public ticker (last/bid/ask/24h stats) for a crypto trading pair on one exchange.' This clearly distinguishes it from sibling tools, and the later line explicitly says not to use it for candles/history or cross-exchange premium.

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?

It gives concrete use cases ('current bitcoin price', 'BTC price in Korea') and explicit exclusions: 'Don't use for candles/history (get_crypto_ohlcv) or cross-exchange premium (compare_crypto_exchanges). This tells an agent exactly when to select this tool over alternatives.

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