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 so well: it explicitly states the operation is read-only, that rewards credit the SHOPPING balance and are not withdrawable, and that an api_key is required. This is clear behavioral disclosure for a query-only tool.

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 well-organized with a clear purpose statement, usage directive, and behavioral note. The Vietnamese repetition at the end adds length but may serve a bilingual audience; overall it remains compact and 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 the tool's simple read-only nature, the description fully equips an agent: what it returns, when to call it, what to do after, and the key behavioral caveat (SHOPPING balance, not withdrawable). No output schema exists, but the described content is sufficient for correct invocation.

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 input schema covers both parameters and their meanings (language and API key), and the description adds that api_key is required)Skip. However, the description repeats 'Requires api_key' already in schema and does not add semantic value beyond the 100% schema coverage, so the baseline 3 applies.

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 states a specific verb and resource: 'One-shot overview of all FREE balance rewards' the account can grab right now, and enumerates the exact areas (daily check-in, lucky wheel, quest board). It clearly distinguishes this aggregate status tool from the individual action siblings like daily_checkin, spin_wheel, and list_quests.

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?

Contains an explicit 'WHEN TO USE' directive: call this first whenever the user asks about rewards/free balance, then follow up with the specific collection tools. This gives unmissable routing and sequencing guidance and names the sibling tools directly.

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