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

Annotations already declare readOnly/idempotent/non-destructive/open-world, so the safety profile is covered. The description adds genuinely new context: a per-call cost ($0.005), UTC timezone, and the specific calendar sources, all of which help an agent decide whether to spend the call.

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?

Two dense sentences that front-load the returned value and sources, then close with the usage cue. No filler, though the source list is somewhat packed.

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 usefully enumerates the event categories and timezone, giving the agent a clear sense of the payload. It could say more about the response structure (e.g., per-event fields), but coverage is solid for a read-only lookup tool.

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% with enums and defaults documented for all three parameters, so the schema carries the load. The description adds only the implicit UTC/importance framing, not parameter-specific syntax beyond that. 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?

States specifically what is returned (next market-moving events in UTC with importance) and names the authoritative sources (BLS, BEA, FOMC, ECB). This differentiates it from generic news/market siblings, though it never explicitly contrasts itself with news.symbol or market.explain_move.

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?

"Check before opening a position" gives a clear, actionable context for when to call it, and the cost signal ($0.005) helps an agent weigh the call. There is no explicit exclusion or named alternative, 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.