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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered without the description. The description adds useful content about what the statistics include, but says nothing about behavior when dates are omitted (both default to null), the time basis of the archive, or result ordering.

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?

A single sentence that front-loads the verb and resource and then lists the returned dimensions. No filler, no redundancy with the 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?

An output schema exists, so return values need not be explained, and annotations cover the safety profile. The remaining gap is parameter behavior: the two date filters are undocumented in both schema and description, which is a meaningful omission for a date-scoped stats 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 0%, so the description must compensate. It refers to 'a date range', implying from_date/to_date, but gives no expected format, no note that both default to null, and no clarification of what an unbounded range means. The agent is left to guess the date syntax.

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?

Uses a specific verb ('Get statistics') on a specific resource ('bundled JavaScript across the archive') and enumerates the measurements returned (share of bundled files, breakdown by bundler and module format). This is clearly distinguishable from siblings like get_jsfingerprint_library_stats or search_js_fingerprint_by_bundler, which cover different slices of the same corpus.

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 the aggregation use case ('across the archive for a date range'), so an agent can infer this is for aggregate reporting rather than per-record lookup. However, it names no alternatives such as search_jsfingerprint_by_bundler when the agent actually wants individual fingerprints, and gives no explicit when-not-to-use guidance.

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