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

With readOnlyHint=true already covering the safety profile, the description still adds real operational context: the paginated response shape {page, per_page, pages, items}, that passwords are redacted, and the underlying endpoint. Redaction in particular is a behavior an agent cannot infer from annotations.

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 short sentences, zero filler, with the verb+resource front-loaded and pagination/redaction details following tightly. 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?

No output schema exists, so the description helpfully supplies the return shape and notes redaction, which covers the main unknown. Minor gaps remain (e.g. sorting, total count), but for a read-only paginated list tool it is essentially complete.

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 page, tags, region, and per_page are fully documented in the schema. The description only gestures at region and tag filtering, adding little syntax or format detail beyond the structured fields, so the 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?

States a specific verb and resource ('List compute instances') plus the scoping dimension ('in a region, optionally filtered by tags'). This clearly separates it from siblings like civo_get_instance (single) and civo_list_instance_sizes.

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?

Gives clear context: region-scoped listing with optional tag filtering, a pointer to civo_list_regions for region codes, and the CIVO_REGION default. It stops short of naming when to prefer an alternative (e.g. get_instance for a single item), so it lacks explicit exclusions.

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