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

With no annotations present, the description carries the full burden, and it does well by disclosing server-side verification from real data, idempotency ('a second call will not double-credit'), and that rewards credit the SHOPPING balance and are not withdrawable. It does not describe the success/failure response format, but the core behavioral contract is clearly documented.

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 main action is front-loaded, and labeled sections like PREREQUISITE, WHEN TO USE, and PREFER INSTEAD make the guidance scannable. Minor redundancy exists: 'Requires api_key' repeats the schema requirement, and the Vietnamese sentence largely duplicates the English content without adding new information.

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 mutation-style claim tool with no annotations and no output schema, this description is unusually complete: it covers the prerequisite state, idempotency, reward destination, non-withdrawability, and correct sibling routing. An agent can confidently execute the intended sequence: use list_quests to find a claimable quest_key, then call claim_quest.

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%, so the baseline is 3; the description adds meaningful context by specifying that quest_key must be complete-but-unclaimed and can be sourced from list_quests or gamefi_status. It also reinforces the idempotent behavior around the quest_key parameter, going beyond mere field labels.

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 precise verb and resource: 'Claim the reward for ONE completed quest', and differentiates itself from sibling reward tools by emphasizing the single-claim scope and 'one claim per quest per period'. It explicitly names what it is not for by routing to list_quests and daily_checkin/spin_wheel, so an agent can distinguish it without opening schemas.

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?

Provides explicit 'WHEN TO USE' and 'PREREQUISITE' sections, requiring a quest_key that is complete-but-unclaimed from list_quests or gamefi_status. It also tells the agent when to prefer alternatives, such as list_quests to discover claimable quests and daily_checkin/spin_wheel for those specific reward types.

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