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

Annotations already declare readOnly=true, idempotent=true, non-destructive, and closed-world, so the safety profile needs no restating. The description adds real value by disclosing the payload contents, notably the usage-vs-limit comparison and next-plan upsell framing, which tells the agent what questions this call can answer. It stops short of noting data freshness or whether limits are hard or soft caps.

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 dense sentence, front-loaded with the core subject, and every listed clause names a distinct returned field rather than padding. Nothing could be removed without losing information.

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 parameters and no output schema, the description carries the burden of describing return values, and it does so by enumerating five payload areas. A minor residual gap is that field formats, units, and currency are unstated, but for a zero-argument read tool this is largely adequate.

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 are zero parameters, so per the baseline this scores 4. The description correctly implies a no-argument, tenant-scoped call, and nothing about the empty schema is left ambiguous.

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 enumerates the specific resources returned: current plan, billing cycle, wallet, active-job usage vs limit, and next-plan unlocks. That is more informative than a tautology and clearly identifies the tenant-scoped snapshot, though it uses a noun phrase with no verb and does not distinguish itself from the sibling get_membership_plans by name.

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: 'Employer's current plan' signals this is the tool for checking one's own subscription state rather than catalogs of available plans. No explicit when-to-use, no named alternatives such as get_membership_plans for plan options or start_plan_upgrade for changing plans, so the agent must infer routing from sibling names.

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