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

Annotations only supply readOnlyHint=true, and the description adds substantial non-obvious behavior: it pulls live trivy-operator compliance reports over the 'agent relay', and critically defines the failure semantics — a cluster that cannot be reached reads as 'not_available' with a reason, 'never as compliant'. That last clause is the kind of safety-relevant guarantee annotations cannot express.

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 dense sentences that are front-loaded with the resource and scope, then layer the coverage/failure caveat. Dense but every clause carries meaning; slightly heavy for a no-parameter tool but not padded.

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 no-param, no-output-schema read tool, the description covers what is returned (per-cluster benchmark results, config-audit totals, freshness), what is omitted and why (baseline not enabled, agent offline), the read-only nature, and the honest failure mode. Nothing an agent needs to interpret the result correctly is missing.

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?

Zero parameters, so per the rubric the baseline is 4. The description also implicitly scopes the data source (trivy-operator compliance reports) and the freshness dimension, adding context beyond an empty schema.

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 ('compliance rollup across every scanned cluster') and enumerates exactly what the rollup contains (per-cluster CIS/NSA-CISA benchmark pass/fail, config-audit totals, scanner freshness). An agent can distinguish this fleet-level compliance summary from siblings like get_security_compliance_framework_report or list_security_cluster_posture without opening any schema.

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 makes the scope clear (every scanned cluster, org-wide rollup), which implies 'use when you want a fleet-wide compliance summary rather than a single-cluster or single-framework view'. However, it never explicitly names an alternative or states when NOT to use it, so the agent must infer the routing from scope alone.

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