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

The annotations only state readOnly, idempotent, and non-destructive hints. The description goes well beyond this by detailing the provider fallback chain (CoinGecko → Coinbase → cached verified value), the disclosure of cached value age, and the 'when verified' caveat on market capitalization. This is genuinely valuable behavioral context that an agent needs before trusting the result.

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?

Three sentences with no waste. The purpose is front-loaded, the fallback chain is compactly stated, and the return fields are listed in one sentence. Every sentence contributes essential 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?

Given the tool's moderate complexityholistically, the description covers the core purpose, provider fallback behavior, cached-data staleness, and return fields. The presence of an output schema and safety annotations fills remaining structural gaps. The description is sufficient for an agent to select and invoke the tool 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%, with both 'coin' and 'symbol' fully described including the supported coin list and case-sensitivity. The description adds little beyond the schema — only the phrase 'supported coins' is a slight reinforcement. Baseline 3 is appropriate because the schema carries the parameter documentation burden.

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: 'Real-time cryptocurrency price lookup.' This immediately states what the tool does and distinguishes it from the unrelated sibling tools (ghost_audit, leadsignal, etc.). It also lists the returned fields, reinforcing purpose.

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?

Usage context is implied through 'Real-time cryptocurrency price lookup' — an agent can infer when to use it. However, there is no explicit when-to-use or when-not-to-use guidance, and no alternatives are named. Since no sibling tool appears to offer price lookups, the absence is not damaging, but the guidance is not explicit.

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