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

Adds substantial behavior beyond the annotations: the question is identical for every conversation and pre-validated for a single correct answer, the answer and explanation are deliberately withheld, and attempt counting is per-conversation. This also explains why readOnlyHint=false and idempotentHint=false apply — calling it has a side effect on attempt state.

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?

Four short sentences, front-loaded with the core purpose, then returns, then constraints. Minor redundancy: the 'English only; lang hi is rejected' clause restates what the lang schema description already says, costing a little space.

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 carries the return-value burden and does so: it names the returned fields (exam, difficulty, expected time) and explicitly lists what is omitted. Combined with the language and attempt-counting rules, an agent has everything needed to call it correctly.

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 both lang and attemptId are already fully documented in the schema, including the same 'per conversation, not per person' and 'hi is rejected' phrasing that appears in the description. The description adds no syntax, format, or lifecycle detail beyond the schema, 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?

Specific verb and resource ('Fetch today's Quant Daily drill'), scoped to GRE/GMAT quant, with an explicit statement of what is returned (exam, difficulty, expected time) and what is not (answer, worked explanation). It is clearly separable from get_practice_drill and get_drill_hint by implication, though it never names those siblings directly.

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?

Gives concrete usage constraints: English only, 'hi' is rejected, attemptId must be reused across calls in a conversation, and attempts are counted per conversation rather than per person. It stops short of explicitly stating when to prefer get_practice_drill or get_drill_hint over this tool, so the alternative-condition guidance is inferred rather than stated.

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