Instance settings

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

Annotations already declare readOnlyHint=true, so the description isn't burdened with safety claims. It still adds real value by disclosing that secrets are masked and that provenance (env vs db) and ignored keys are part of the result — traits an agent needs to interpret the output correctly.

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?

Front-loaded with the purpose and audience, then the return shape. The long parenthetical setting list is dense but earns its place by telling the agent what is covered before it calls.

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 present, the description fully compensates by spelling out the return object's fields (values, env, override, source, ignored, groups, help, updatedAt/updatedBy). Nothing needed to call or interpret it is absent.

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 the baseline is 4 by rule. No parameter meaning is missing because there is nothing to document.

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 ('the instance settings in force') and enumerates the domains covered (sign-up mode, quotas, retention, etc.) plus provenance. An agent can distinguish it from the mutation sibling set_instance_settings without opening a 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?

'Admins only' gives a clear access prerequisite, and the read-only framing implies inspection usage. But it never names set_instance_settings as the write alternative or says when to prefer this tool over sibling lookups like check_for_update or get_billing.

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