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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds the cross-link rollup behavior, but says nothing about the time window (no date parameters exist, so the aggregation scope is unclear) or whether idempotentHint=false has any practical effect for a read report.

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?

A single tight sentence with the aggregation key front-loaded and no wasted preamble. The trailing 'campaign performance' label is mildly redundant with the title, keeping it just short of a 5.

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?

An output schema exists, so return values need no explanation, and annotations cover safety. However, for a report tool the absence of any stated time range or filtering behavior leaves a real gap an agent cannot resolve from the structured fields.

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% and the single workspaceId parameter is fully documented in the schema (including the 'omit for token's own space' default). The description adds nothing about the parameter, so 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 aggregation ('clicks rolled up by utm_campaign') and an explicit scope ('across every link'), which distinguishes it from the per-link sibling snipzr_get_link_stats. It never names the sibling, so the differentiation is inferable rather than explicit.

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?

Usage is only implied by the phrase 'campaign performance' — an agent can guess this is the tool for campaign-level rollups, but there is no when-to-use vs. get_link_stats guidance and no stated prerequisites or exclusions.

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