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

Annotations already establish readOnly, idempotent, non-destructive, and closed-world behavior, so the bar is lower; the description still adds real value by naming the required authorization scope and confirming the call is free. It does not cover freshness/refresh cadence of the counters, but nothing is contradicted.

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?

A single compact sentence that front-loads what is returned, followed by the two operational facts (scope, cost). Every clause carries information and nothing is redundant.

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 no output schema, the description must convey the return shape, and it lists the three data categories returned. The remaining gap is sibling disambiguation against get_credit_balance and any note on data freshness.

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?

The tool takes zero parameters, so there is no parameter semantics to document and the baseline of 4 applies. The description correctly implies no inputs are needed by framing it as a fixed stats read.

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 resource ('API usage statistics') and enumerates the contents: credit balance, API call counts (today/total), and recent credit transactions. Clear enough to know what comes back, but it does not distinguish itself from the sibling 'autoshort_get_credit_balance', which covers overlapping 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 prerequisite ('Requires the "usage:read" scope') and cost note ('Free') give useful context for deciding whether the call will succeed, but there is no explicit when-to-use guidance versus get_credit_balance or get_limits, which overlap with the stats returned here.

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