GA4: Realtime

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuine context beyond that with the ~30 minute data window, but omits realtime-specific constraints such as quota/rate limits and the fact that only realtime-compatible dimensions can be requested.

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 compact sentences with the resource identity and time window front-loaded, and examples attached to the parameters that need them. The telegraphic 'e.g.' style stays readable, though the parenthetical API-method citation is of marginal value to an agent.

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 5-param, no-output-schema tool with a nested filter object, this covers the essentials: scope, required metrics, and dimension examples. It stops short of describing the returned rows/totals and omits the limit and dimensionFilter semantics, but the schema and its cross-reference handle the filter.

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 coverage is 60%, with property and dimensionFilter documented in-schema. The description adds real meaning for dimensions (concrete examples: unifiedScreenName, country, deviceCategory) which the schema leaves bare, but says nothing about limit or about which dimensions are valid in realtime.

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 verb and resource (realtime report), cites the underlying API method runRealtimeReport, and states the scope window (~last 30 min). That window is what distinguishes it from the sibling ga4_run_report, though the description never names that sibling explicitly.

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 '~30 min' framing implies this is for live/traffic monitoring rather than historical analysis, which implicitly routes against ga4_run_report. However, there is no explicit statement of when to prefer this over ga4_run_report or what to do when realtime data is unavailable.

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