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

Annotations already declare readOnlyHint, and the description usefully adds account-tier prerequisites, the specific error returned for ineligible accounts, and the grouping rule (stores bucketed by current workspace across all viewable workspaces). That is real behavioral context beyond the annotation. It stops short of describing pagination, result size or refresh semantics.

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 body is dense and front-loaded with the core concept, which is good, but it ends with a stray artifact '[#65a008]' that carries no meaning for an agent and slightly undermines trust in the text. The middle sentence about store rollups is jargon-heavy relative to its value.

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?

No output schema exists, so the description carries some burden for the return shape; it names 'per-workspace KPIs plus rolled-up totals' but not the concrete metric fields or result structure. Prerequisites and error behavior are covered, so the definition is adequate but incomplete for a 4-parameter analytics tool.

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 schema already documents all four parameters including date defaults and currency segmentation. The description adds only the conceptual framing of 'per-workspace' grouping, which loosely motivates the workspace parameter but supplies no syntax or constraint the schema lacks. Baseline 3 applies.

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 resource (cross-client portfolio KPIs with rolled-up totals) and frames it as 'the agency view', which is a meaningful distinction. It does not, however, name the sibling analytics tools (analytics_summary, analytics_breakdown, analytics_timeseries) it must be chosen over, leaving that differentiation to inference.

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?

It gives one strong usage gate — requires an agency (Enterprise) account with Advanced Analytics, otherwise a feature_unavailable error — but gives no explicit when-to-use comparison against the sibling analytics_* tools. The agent must infer that 'cross-client' means this tool is for agency rollups and not single-workspace queries.

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