List cloud regions

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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds one useful behavioral detail: each region is paired with its electricity grid zone. It does not discuss result ordering, pagination, or data source quirks, but for a simple read-only listing this is acceptable; a 3 is appropriate.

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?

The description is a single sentence with zero filler. It front-loads the action and resource, then appends the key output detail. Every word 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?

Given the tool's low complexity, rich annotations, 100% schema coverage, and existing output schema, the description is nearly complete. The only gap is the absence of explicit routing versus sibling tools, but this does not block correct invocation for the main use case.

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% and both optional filter parameters (country, provider) are fully documented in the schema. The description itself adds no additional parameter-level meaning, so it sits at the baseline 3.

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?

The description uses a specific verb ('List') with a concrete resource ('cloud regions Eco Router knows about') and states the key distinguishing output ('electricity grid zone'). This clearly separates it from siblings like rank_regions and find_clean_window, which imply different operations.

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 clearly implies the tool is for listing all known cloud regions, but it never explicitly states when to prefer this over rank_regions or find_clean_window, nor does it mention any exclusions. The usage context is clear but the alternatives are only inferable from sibling names, not articulated.

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