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

Annotations only cover readOnlyHint=true. The description adds real behavioral context beyond them: the pagination envelope shape, that passwords are redacted in the response, and the underlying endpoint. It still omits anything about rate limits or total result caps, so not a 5.

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?

Three tight sentences with no filler. Scope is front-loaded, pagination and redaction details follow, and the endpoint reference trails — every clause earns its place.

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?

With no output schema, the description usefully supplies the pagination envelope {page, per_page, pages, items} and notes password redaction, plus region default via the schema. Minor gap: no note on total page behavior or empty results, but an agent has enough to call it 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 description coverage is 100%, so the baseline is 3. The description only restates the region and tag filters in prose; it adds no syntax, default, or edge-case detail beyond what the schema already documents.

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 (List) and resource (compute instances) with scope modifiers (in a region, optionally filtered by tags). This is clearly distinguishable from siblings like civo_get_instance or civo_list_instance_sizes 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?

Usage is implied by the read/list nature and the tag filter, but there is no explicit when-to-use versus when-not, and no sibling is named as an alternative (e.g., use civo_get_instance for a single instance). Adequate minimum-viable guidance only.

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