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

With no annotations provided, the description carries the full burden and does well: it implies read-only behavior via 'Check', explicitly requires the vm_live_ API key, and adds a meaningful guarantee that the wallet never changes pricing or the 95/5 split. This discloses auth and non-mutational behavior beyond what structured fields provide.

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?

Two sentences, front-loaded with the action and resource, followed by a compact list of covered data points. Every phrase adds value—no filler or repetition. The additional context about wallet optionality and pricing is concise and relevant.

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?

The tool is simple (one parameter, no output schema), and the description fully explains what the response includes (balance, funding totals, auto-recharge, card status, cap, activity) and key context (optionality, no pricing impact). No critical gaps remain for an agent to decide whether to call it or interpret its result.

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 only parameter, api_key, has 100% schema description coverage ('Your vm_live_ API key'). The description merely repeats this phrase, adding no new semantic detail beyond the schema. Baseline 3 applies since the schema already documents the parameter.

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 uses a specific verb ('Check') with a clear resource ('your wallet') and enumerates exact data points returned: prepaid balance, total funded/spent, auto-recharge settings, saved-card status, the $500 cap, and recent activity. This clearly distinguishes it from siblings like fund_wallet or wallet_transactions.

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 clearly states what the tool covers (wallet overview) and adds context about the wallet being optional and not affecting pricing/split. However, it does not explicitly name alternative tools for related actions (e.g., fund_wallet, wallet_transactions) or state when not to use it, so it falls short of fully explicit usage guidance.

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