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

Annotations already convey read-only and idempotent behavior. The description adds useful behavioral context: 60s server-side caching, automatic ticker mapping, use of the public CoinGecko API, and preflighting to avoid paying during outages. This goes beyond the structural annotations and helps an agent understand edge-case behavior.

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?

Two dense sentences with no filler. The primary purpose is front-loaded, followed by caching and outage behavior. Every sentence contributes meaningful information.

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 one-parameter read-only tool with a full input schema and an output schema, the description covers the essential operational details: price type, currency, API source, ticker mapping, caching, and outage handling. Nothing needed for correct invocation is missing.

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% and the single symbol parameter is already well described. The description adds value by explaining that common tickers are mapped to CoinGecko ids automatically and by providing an example, which clarifies accepted input formats beyond the schema alone.

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 clearly states the tool returns the current USD spot price for a symbol via CoinGecko, which identifies the verb-like operation, resource, and output. The mention of automatic ticker-to-id mapping further clarifies scope and differentiates it from the many validation/check 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 clearly implies when to use it: whenever a current crypto spot price is needed. It also provides context about caching and outage resilience, but does not name explicit alternative tools or when-not-to-use conditions. This is clear context without exclusions.

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