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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful context: the data is derived from public chart JSON and is explicitly 'not investment advice or real-time trading data', which clarifies freshness and nature of the output beyond the 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 short and front-loads the core purpose before the routing hint. The disclaimer sentence is slightly awkward in placement but still earns its place by warning about non-real-time data.

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?

With an output schema present, return values need not be explained, and annotations cover safety. Still, given four parameters and multiple chart-related siblings, the description could be more complete about selection criteria and the vs_currency/range enum constraints.

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 schema already documents all four parameters with enums and slugs. The description only restates the 'id' parameter definition, adding no meaning beyond what the schema provides, so the baseline 3 applies.

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?

States a specific verb+resource ('Returns derived price-chart metrics from CoinGecko public chart JSON') and contrasts itself with a sibling by pointing to coingecko_coin for profile data. However, 'derived price-chart metrics' remains somewhat abstract about what metrics are actually returned.

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 one routing hint ('Use coingecko_coin to retrieve coinGecko coin profile'), which tells the agent when NOT to use this tool, but offers no explicit condition for when this analysis tool is the right choice versus other chart-related siblings like coingecko_global_charts.

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