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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds behavioral context beyond annotations by stating 'calls preserved as captured, so deletion does not scrub the record', indicating immutability, and mentions measurement against real on-chain prices. No contradiction.

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 concise, with four sentences each adding value. It front-loads the purpose, lists output fields, and ends with a usage guideline. No fluff.

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?

Without an output schema, the description lists key return fields (early_rate, momentum_rate, median 1h forward return, etc.) and explains data source. This is sufficient for a report card tool, though some detail on output format is omitted.

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%, fully documenting the 'handle' parameter. The description does not add new semantic information about the parameter beyond what the schema provides, so it meets the baseline for high coverage.

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 explicitly states it provides a 'Free MEASURED track record' for an X account that called tokens, listing specific metrics like early_rate and momentum_rate. It distinguishes itself from siblings by focusing on a report card for a single caller, not a list of calls or callers.

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 includes 'Use before trusting any "alpha caller"' as a clear usage guideline. While it doesn't explicitly exclude other uses, this directive provides clear context for when to apply the tool.

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