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

Annotations already establish read-only, idempotent, non-destructive, open-world behavior. The description adds genuinely new behavioral context: the paid-tier gating (unauthenticated users see only the next 3 high-impact events, free/Pro see the full calendar), which an agent needs to interpret truncated results correctly.

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?

Three short sentences: capability, usage trigger, access-tier constraint. Front-loaded with what matters most and no filler or restated title.

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 one-optional-param read tool with no output schema, the description covers content returned, trigger conditions, and access limits. It does not say whether the calendar includes past/upcoming windowing or result size beyond the tier cap, which is a minor but real gap.

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% and the single optional 'impact' filter is fully documented there, so the baseline is 3. The description echoes 'impact level' and mentions 'high-impact,' but adds no format or semantics beyond the schema's high/medium/low enumeration.

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 specific resource (US macro events: CPI, FOMC, jobs, GDP) plus what each entry carries (impact level, historically reacting ETFs). That is clearly distinguishable from siblings like earnings_calendar, dividends, or stock_news without opening a schema.

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 an explicit invocation trigger ('what macro events are coming up?'), which is exactly the routing cue an agent needs. It does not name alternatives (e.g., earnings_calendar for company-specific events) or state when not to use it, so it falls short of a 5.

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