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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds valuable behavioral context: it returns only aggregated counts/totals, not individual rows, and notes the data is a recent audited window, not a lifetime ledger. This goes 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 three sentences, front-loaded with the main purpose, and each sentence adds critical information (aggregate, trend, public, no auth, window limitation). No wasted words.

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 single parameter, high schema coverage, and presence of an output schema, the description is remarkably complete. It covers the nature of the data, auth requirements, and temporal scope, leaving no major gaps for the agent.

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 description does not add meaning beyond the schema's parameter description. The schema already provides 'Username whose karma provenance to fetch.' Baseline score of 3 is appropriate because the description does not enhance parameter understanding.

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's purpose: 'Aggregate breakdown of how a user earned their karma, grouped by reason, plus a 30/90-day trend.' It specifies the scope (aggregates only, never individual rows) and data type (counts + totals), distinguishing it from any tool that might provide raw adjustment data.

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 provides clear usage context: 'Public — aggregates only' and 'No auth required.' While it does not explicitly mention alternatives, it implies this tool is for aggregate karma views, which is straightforward for the agent given the sibling list lacks similar tools.

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