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

Annotations already declare readOnlyHint/openWorldHint, but the description adds genuinely useful behavioral context they do not carry: the cost ($0.03 USDC per call), the payment modes (x402 or prepaid credits), and the fact it is excluded from the free trial. It also discloses the aggregation-plus-synthesis behavior and citation numbering. It does not, however, explain why idempotentHint is false (results vary over time), which would be valuable.

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 purpose and output shape are front-loaded in the first sentence, with pricing and eligibility following. It is efficient overall, though the $0.03 price is duplicated from the title and 'Built for research agents' is mild filler.

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?

Output schema and annotations already cover return values and safety, so the description's job is to add the source/time/cost context an agent needs to call it correctly, which it does. What is missing is the reason for non-idempotent results and any explicit routing versus sibling research tools.

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 description coverage is 100%, so the schema already documents q, days, limit and sources. The description only echoes the time window ('last 1-30 days') and does not add syntax or meaning beyond the schema. Baseline 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?

The description names a specific verb+resource: produces an AI research briefing on a topic from the last 1-30 days, explicitly listing the aggregation sources (Hacker News, Reddit, GDELT) and the briefing contents (developments, sentiment, what to watch, citations). An agent can tell this apart from a raw feed or summarise tool. It stops short of naming a sibling alternative for direct comparison, so it lands at 4 rather than 5.

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?

'Built for research agents' and the 1-30 day window imply the intended use case, but there is no explicit guidance on when to prefer this over siblings like news, search-answer, summarise or report-topic, nor any when-not condition. Usage is implied rather than stated.

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