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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is fully covered structurally. The description reinforces read-only and adds that billing mutations are portal-only, but contributes little new behavioral detail (no auth requirements or response format notes).

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 front-loaded sentence carries the resource, endpoint, read-only nature, output fields, and the billing-mutation constraint with no filler. The trailing 'Read tier.' is a minor fragment but harmless.

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 compensates by naming the two values an agent gets back (plan tier and billing exemption). It omits whether the result is empty or errors for orgs without a plan, but is otherwise sufficient for a zero-parameter read.

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, so the baseline of 4 applies. The description uses the space usefully by describing the returned fields rather than restating parameters.

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?

Names a specific verb+resource ('Your organization's plan') and enumerates what it returns: plan tier (free, pro, ...) and billing-exemption status. It doesn't explicitly contrast with nearby read siblings like tascan_get_org or tascan_get_budget, but the resource is narrow enough to be distinguishable.

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?

States a clear constraint: 'Billing changes happen in the TaScan portal only,' which tells the agent not to attempt plan changes through this tool. It gives context without naming a sibling alternative, so it falls just short of a 5.

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