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

Annotations already declare the read-only, idempotent, non-destructive, closed-world profile, so the bar is lower. The description adds genuinely useful behavior beyond them: plan gating and a graceful failure mode (upgrade message returned rather than an error), plus a description of the returned content.

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 tightly packed sentences with the purpose front-loaded and the plan constraint second. No filler, though the first sentence is a slightly dense list that could be parsed more quickly.

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 helpfully characterizes the return payload (per-platform guidance with source links) and the plan-gated edge case. It does not state the return format (list vs. object) or volume, but for a 0-param read tool it is nearly complete.

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?

The tool takes zero parameters, so the schema carries no parameter semantics burden; the baseline for a 0-param tool is 4. No parameter detail is needed or missing.

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 verb+resource ('Get per-platform growth playbooks') and enumerates the payload (cadence, format, timing, anti-spam guidance, source links). It is clearly distinguishable from siblings like list_growth_opportunities or get_growth_overview by its documentation-derived content, though it does not name a sibling explicitly.

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?

Provides a concrete prerequisite ('Requires the Empire plan; on other plans it returns an upgrade message'), which tells the agent when it will succeed. However, it gives no comparative guidance on when to prefer this over related tools such as get_growth_overview or list_growth_opportunities.

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