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

No annotations are provided, so the description carries the transparency burden. It discloses the live spot price nature, the CoinGecko listing scope, and the exact return fields, which is meaningful behavioral context. However, it does not mention error conditions, rate limits, or data freshness, which keeps it a 4 rather than a 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?

The description is a well-structured paragraph with no filler. Every sentence contributes either the core function, the return payload, supported asset examples, or usage guidance with alternatives. The length is justified by the need to differentiate from several closely related sibling tools.

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 tool with 3 parameters and no output schema, the description fully covers what the tool returns, the accepted input scope, and the conditions for use versus alternatives. It even warns against historical use. The context is sufficiently complete 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 description coverage is 100%, so the baseline is 3. The description reinforces the purpose of include_market_data ('full market picture') and gives examples of accepted coin symbols, but the schema already thoroughly describes all parameters. The description adds marginal value beyond the schema.

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 begins with a specific verb and resource: 'Retrieves real-time price data for any cryptocurrency listed on CoinGecko.' It clearly enumerates the returned data (price, 24h change, market cap, volume) and distinguishes itself from sibling tools by explicitly referencing crypto_price_lite and crypto_fx_rates.

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?

Provides explicit when-to-use guidance ('Use crypto_price when an agent needs the full market picture'), when to prefer alternatives ('Prefer crypto_price_lite', 'Use crypto_fx_rates'), and exclusions ('Do not use for fiat-to-fiat', 'Do not use when historical data required'). This is textbook-level guidance.

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