databases_list

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

Annotations already declare readOnlyHint=true, so the safety profile is covered; the description adds genuinely new behavioral context by naming the required OAuth scope 'databases:read' and by previewing the fields returned per cluster. It omits pagination or result-limit behavior, which keeps it below 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?

Two short fragments, front-loaded with the resource and its returned attributes, with zero filler. The clipped phrasing ('with status, plan and region. Scope databases:read.') reads as telegraphic notes rather than complete sentences, which slightly hurts readability but not efficiency.

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 parameterless read-only list with no output schema, the description supplies the two things an agent actually needs: what comes back and what scope is required. Only the absence of any result-size or pagination expectation keeps it from being fully 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The description does not need to compensate for any schema gap here.

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?

Names a specific resource ('Your managed PostgreSQL clusters') and enumerates what each entry carries (status, plan, region), which is more than the title alone provides. It never states the verb explicitly — 'list' must be inferred from the tool name — and it does not distinguish itself from the sibling databases_get, so it stops short of a 5.

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?

There is no statement of when to use this versus databases_get or the other list_* siblings, and no exclusions. The only contextual cue is the required scope, which functions as an auth prerequisite rather than usage guidance.

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