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

Annotations already establish readOnly/idempotent/non-destructive, so the bar is lower. The description adds genuinely useful context beyond them: an uncached query can take up to 90 seconds, and results include target URL, overall risk, and time.

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 tight sentences with zero waste. The core purpose and the signature example are front-loaded, and the latency caveat is a compact second sentence.

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 little explanation, and the description still adds latency and result fields. For a 2-param search tool this is close to complete, with only 'limit' semantics unaddressed.

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 0%, so the description must compensate. It explains the signature format well via the 'setTimeout:30|fetch:4|complex' example, but says nothing about the 'limit' parameter (its meaning or default of 20), leaving one of two params undocumented.

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+resource: finds scans matching a behavioural signature, and gives a concrete example of the signature format. It is distinguishable from runtime siblings like search_js_runtime_by_composite_hash, though it does not explicitly name the alternative that replaces it.

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 resource ('find scans with this signature'), but there is no explicit when-to-use/when-not guidance and no routing to the many sibling search tools. The latency note is the only operational hint.

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