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

With no annotations, the description carries the full burden, and it discloses useful behavior: a hard cap of 5 observations, newest-first ordering, empty-array-on-none, and typical <300ms latency from a cached corpus read (implying a safe read). It omits auth/permission requirements and any rate-limit detail, so not fully transparent.

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?

Front-loads the purpose, then uses labeled sections (Use this tool when / Inputs / Returns / Latency) that each add distinct value. No filler or repetition; the structure aids scanning.

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?

Despite no output schema, the description documents the return shape (`domain`, `observations[]` with cap and ordering), the input, and latency — everything needed to call a simple lookup correctly.

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% and the single parameter has no schema description, so the description must compensate — and it does by labeling `domain` as path/required and a 'hostname', clarifying the expected value type. Only one parameter exists, so little more is needed.

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 ('Returns the five most recent CT certificate observations... for a domain') with the exact fields returned (issuer CA, jurisdiction, validity) and ordering. The line 'The certificate leg of the sovereignty check, on its own' differentiates it from the broader sibling ghostroute_check/ghostroute_verify.

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?

Provides explicit 'Use this tool when:' bullets covering two concrete conditions (which CA issues certs; whether the issuer sits in the claimed jurisdiction). Clear context for selection, but it names no alternatives (e.g. ghostroute_ct_alerts, ghostroute_ct_proofs) and gives no when-not-to-use exclusion.

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