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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so risk is covered structurally. The description adds value by disclosing the return content (balance, unit costs, how many of each are affordable), which matters because no output schema exists. It stops short of noting unit/currency or freshness of the balance, so it is strong but not exhaustive.

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, no padding: the first states what is returned, the second states when to call it. Content is front-loaded with the resource and the payload, and the conditional clause is tight.

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?

For a zero-parameter, read-only lookup with no output schema, describing the returned fields and the pre-flight call ordering is exactly what an agent needs. Nothing required for correct invocation 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?

Zero parameters means there is nothing to disambiguate, so the baseline is 4. The description correctly implies a workspace-scoped, no-argument call rather than suggesting any filters.

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 names the exact resource (workspace credit balance) and enumerates the specific payload: balance, per-carousel and per-video cost, and coverage counts. That is far more specific than the title and clearly distinguishes it from analytics/reporting siblings like get_analytics_overview.

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 an explicit trigger ('Call this before make_carousel or make_video when the balance is unknown') and names the two consuming tools. The agent knows both when to call it and which siblings it precedes, with no inference required.

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