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

With only readOnlyHint/openWorldHint in annotations, the description carries real behavioral weight: it discloses that individual entries exclude bots, that aiTraffic/cities/QR scans are Pro-and-trial-only and come back null on Free, and that plan caps bound the lookback window. Those are exactly the caveats an agent needs to interpret results 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?

Two sentences, front-loaded with the returned metrics, then the plan-gated exceptions. Every clause carries information; parentheses are used to pack qualifiers rather than pad.

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 must convey return shape, and it does by enumerating the metric groups and the fields that may be null. Combined with the plan-cap rules, an agent has enough to call it and interpret the response.

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 100%, so the baseline is 3, but the description adds meaning beyond the schema: it explains that omitting code means whole-account scope and that the maximum value of days is plan-dependent rather than a flat 365. It does not mention the tags filter at all, leaving that parameter to the schema alone.

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 (click analytics) and enumerates exactly what comes back: totals, daily series, countries, devices, browsers, referrers, top links. It also scopes to account-wide vs single-link and flags bot separation. It does not explicitly contrast with the analytics-adjacent sibling compare_tags, so it stops short of a 5.

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?

Clear usage context: omit code for the whole account, pass code for one link, and the plan determines how far back days can reach (Free 30, Pro 365). It never names alternatives or exclusion conditions (e.g., when to prefer compare_tags), so no explicit routing guidance.

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