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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the account-level scope but says nothing about pagination behavior, the default 100-item cap, or how filters combine — all knowable only from the schema, not the prose.

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 front-loaded sentence that names the verb, the resource, and the covered categories with zero filler. Nothing redundant or 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?

An output schema exists, so return values need no explanation, and the schema fully documents all five optional parameters. The remaining gap is routing context — when to prefer this broad lister over the narrower sibling listers — which leaves the definition slightly under-complete for an agent choosing between near-duplicate tools.

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 100%, so every parameter (q, fields, max_items, service_type, port_circuit_id) is already documented in the schema. The description's type enumeration loosely maps to the service_type enum values, adding marginal reinforcement but no new syntax or format detail. Baseline 3 applies.

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?

Specific verb (List) plus resource (the account's virtual circuits / services) with a parenthetical enumerating the covered types (backbone VCs, cloud connections, IX, marketplace). It is clearly broader than sibling listers such as pf_list_cloud_connections or pf_list_point_to_point, but the description never states that relationship, so the distinction is inferable rather than explicit.

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?

No when-to-use guidance, no prerequisites, and no mention of the narrower siblings (pf_list_cloud_connections, pf_list_cloud_router_connections, pf_list_point_to_point) that return subsets of the same data. The agent must guess whether to call this broad lister or a type-specific one.

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