Create Postgres instance

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

Beyond the annotations (readOnlyHint=false, openWorldHint=true, idempotentHint=false), the description discloses that the generated password is only visible in the creation response, which is critical for credential management. It also names the HTTP POST method, implying a non-idempotent create operation with side effects. This adds meaningful behavioral context.

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 first two sentences ('Create Postgres instance. Create a new Postgres instance.') are redundant and could be condensed into one. The remaining sentences are information-dense and useful, covering the API endpoint, version usage, plan source, and password behavior.

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 complexity (17 parameters, nested objects, no output schema), the description highlights essential gotchas (version, plan source, password visibility) but does not explain return structure, asynchronous creation behavior, or external side effects. It is adequate as a minimum viable description but has clear gaps.

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 only 47%, so the description compensates for a few critical parameters: version format ('major version as a string e.g. "16"') and plan/disk size sourcing from render_list_postgres_sizes. However, most parameters (e.g., ipAllowList, readReplicas, environmentId) receive no additional explanation in the description, leaving a gap.

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 clearly states the action ('Create Postgres instance') and the underlying API call (`POST /postgres`). It is distinct from sibling create tools like render_create_redis or render_create_service. The redundancy in the first two sentences is a minor stylistic issue.

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 provides clear usage context: it specifies that `version` is a major version string, references render_list_postgres_sizes for plan/disk size selection, and advises using render_retrieve_postgres_connection_info for credentials afterward. It does not explicitly state when not to use the tool, but the context is unambiguous.

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