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

Annotations already indicate readOnly and idempotent, so the description adds value by stating public access, aggregates only, and a recent audited window (not lifetime). It does not contradict annotations and provides useful behavioral context beyond what annotations cover.

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 two sentences with a parenthetical note, efficiently conveying the core function, data scope, auth status, and window constraint. Every sentence adds value, and the key information is front-loaded.

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 there is an output schema, the description does not need to detail return values. It covers the tool's purpose, data type (aggregates), trend period, auth requirement, and window constraint, making it complete for a simple read-only tool.

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 a clear parameter description. The tool description does not add extra semantics beyond what the schema already provides for the 'username' parameter. Baseline 3 is appropriate.

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 specifies an aggregate breakdown of karma grouped by reason with a 30/90-day trend. It clearly defines the resource (user's karma) and the action (get breakdown). It distinguishes itself from a lifetime ledger, making the purpose unambiguous.

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 states 'No auth required' and clarifies it returns aggregates only, which guides appropriate usage. However, it does not explicitly mention when to avoid this tool or compare with siblings. Since no other sibling provides karma breakdown, the lack of alternatives is acceptable but not explicit.

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