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

Annotations already establish that this is a read-only, non-destructive operation. The description adds meaningful behavioral context beyond annotations: date-range caps, zero-filled days before data_from, no error for pre-data dates, session attribution on start day, exclusion of blocked/deleted events, and possible discrepancy with get_summary.

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 front-loaded with the core operation and then efficiently adds constraints and data caveats in one dense but purposeful sentence. There is no filler, and every clause contributes operational meaning.

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, the presence of an output schema, complete schema descriptions, and read-only annotations, the description covers the important semantic pitfalls: valid names must come from list_metrics_dimensions, date limits, pre-data zero behavior, and session-counting differences from get_summary. Nothing critical for correct invocation is missing.

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%, so the input schema already documents the parameters in detail. The description reinforces key constraints such as the 0-7 dimensions and 1-10 metrics limits and the page-dimension/page-metric date-range restriction, but most of this repeats schema content rather than adding new parameter-level semantics.

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 a specific verb and resource: it runs an analytics report over Tracklution sessions using a GA4 runReport-shaped API. It distinguishes the tool from get_summary by noting differing session totals and depends on list_metrics_dimensions for valid names, but it does not explicitly differentiate itself from related siblings such as get_report or run_realtime_report.

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 implies that this is the tool for custom reports with date ranges, dimensions, and metrics, and it usefully points to list_metrics_dimensions for valid names. However, it gives no explicit 'use this when...' guidance or side-by-side comparison against related reporting siblings like get_report or run_realtime_report.

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