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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavior: the plan's daily window silently caps results so a larger days value returns fewer days rather than an error, and pagination is always a single page — both are non-obvious and prevent misuse.

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, front-loaded with the core behavior, then the two non-obvious constraints. No filler. The phrase 'counting back from today in Eastern time' slightly restates the following sentence but carries the timezone fact.

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?

No output schema exists, so the description carries return-shape burden; pointing out the single-page pagination and per-day counting gives enough shape to parse the response. The timezone is specified, and the plan-cap behavior is disclosed, leaving only field-level return detail unstated.

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% and already documents days as 1-90 with a default of 30. The description adds the semantic consequence the schema omits: the effective range is capped by the plan window, so overshooting days truncates rather than fails.

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 verb and resource: counts of businesses filed per day, counting back from today in Eastern time. Clear enough to distinguish from a raw listing, but it never names the obvious sibling list_daily_filings, which returns the underlying records rather than aggregates.

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?

Usage is implied by the aggregation framing rather than stated. There is no explicit 'use this when you need counts, use list_daily_filings when you need the filings themselves' guidance, so the agent must infer the choice from the sibling name alone.

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