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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds meaningful extra context: public access, no auth, aggregate-only privacy guarantee (never individual rows), and an audited-window limitation with a window_note field. No contradiction with 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?

Three dense sentences, each earning its place: the core output, the privacy/scope constraints, and the window caveat. Information is front-loaded and there is no filler or redundancy.

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 single-parameter read-only tool with a full input schema, annotations, and an output schema, the description covers auth, data scope, aggregation guarantees, and the window limitation. Nothing essential for an agent to call this correctly is missing.

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%; the schema already documents the single username parameter as accepting a username or user ID. The description adds no additional parameter-level detail beyond referencing the user, so the baseline of 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 clearly states the tool produces an aggregate karma breakdown grouped by reason plus a 30/90-day trend, which is a specific verb+resource combination. It also distinguishes itself from generic history/stats tools by emphasizing aggregates only, not individual adjustment rows.

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 gives clear contextual guidance: it is public, requires no auth, returns aggregates only, and covers a recent audited window rather than a lifetime ledger. It does not explicitly name an alternative tool for lifetime history or per-user details, but the window caveat implies when not to use this tool.

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