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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds genuinely useful behavioral context beyond them: the scope of returned analytics, that non-openers and off-list openers are included, and that detailed analytics are gated behind Pro.

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?

Effectively one dense sentence listing return contents plus a short entitlement caveat. It is front-loaded with the core value and no clause is wasted, though the single sentence is long.

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?

With no output schema, the description must convey what comes back, and it does so thoroughly (views, read time, section breakdowns, per-recipient opens, non-openers, off-list openers). For a one-parameter read tool with full annotation coverage, this is nearly complete; only explicit usage guidance 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?

There is a single parameter with 100% schema description coverage ('The link's slug or id'), so the schema already carries the semantics. The description adds no syntax or format details about the id, making the baseline 3 appropriate.

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 states a specific resource (analytics for one link) and enumerates the concrete outputs — views, read time, section breakdowns, per-recipient opens — plus the non-opener and off-list cases. It is clearly distinguishable from the CRUD-oriented siblings (get_page, list_pages, etc.), though it does not explicitly name an alternative.

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 implied: fetch the report for a single link. There is no explicit when-to-use/when-not guidance or named alternative, but the entitlement note 'Detailed analytics require Pro' gives a real gating condition the agent must know.

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