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

The description adds substantial behavioral context beyond the read-only, idempotent, non-destructive annotations: the 60-day window cap, comparison against a preceding equal-length window, evidence-not-attacks caveat, overlapping classes/sources, withheld nulls, zero-baseline percentage behavior, untrusted source text, sequential calls on the public endpoint, and 429/Retry-After handling. These are meaningful operational and interpretive constraints that the annotations do not cover.

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 is front-loaded and most sentences earn their place by conveying constraints, caveats, or retry behavior. The description is dense and could be structured more clearly, but the length is largely justified by the operational details it must convey.

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 read-only analytics tool with a nested window parameter and no output schema, the description covers window semantics, comparison behavior, grouping, null/percentage handling, and rate-limit behavior well. It stops short of fully describing the output shape, but the remaining gap is relatively minor given the rich behavioral coverage.

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?

The schema already documents window.from, window.to, date patterns, inclusivity, and groupBy enum values, giving 50% coverage overall. The description mainly adds the 60-day cap and reiterates grouping by class, source, or day; it does not add much more parameter-level semantics beyond that.

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 states a specific verb and resource: it compares canonical threat counts over a window against the immediately preceding equal-length window, grouped by class, source, or day. This is clear enough to distinguish trend-analytics behavior from simpler sibling tools, although it does not explicitly name those siblings as alternatives.

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 comparison-over-window framing and the 60-day window limit, but the description does not explicitly say when to use ti_trends versus ti_latest, ti_daily_report, ti_classes, or ti_sources. It gives operational guidance for the public endpoint and 429 responses, but not clear selection guidance among sibling tools.

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