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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the useful scope that results include both upcoming and historical releases, but omits return format, pagination, or rate-limit/auth behavior.

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 tightly written sentences; the core resource and scope are front-loaded before the optional filter detail and source endpoint. No wasted language.

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 simple read-only calendar endpoint with full schema coverage and annotations, the description supplies enough to invoke correctly. It stops short of describing default behavior when no filters are supplied or any facets of the returned calendar entries, which is a minor gap given the absence of an output schema.

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 the from, to, and symbol parameters with format and examples. The description only restates that filtering is optional and by date range/symbol, adding no syntax or constraint detail beyond the schema.

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?

Names the specific resource (earnings release calendar) and its temporal scope (upcoming and historical), which distinguishes it from siblings like finnhub_earnings_surprises and finnhub_ipo_calendar without needing the 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?

The description implies usage for retrieving earnings dates and mentions optional date/symbol filters, but does not state when to use this tool versus alternatives such as finnhub_earnings_surprises or finnhub_ipo_calendar, nor any exclusions.

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