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

Annotations already establish this as a safe, non-open-world read (readOnlyHint=true, openWorldHint=false), so the description only needs to add context. It does so usefully: it discloses that the response centers on a personal upgrade/change-card link and distinguishes free vs. Pro tiers, which is non-obvious behavioral context.

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?

Three short sentences with the core purpose front-loaded and the tier/link details following. Every sentence carries information, though the trailing free-features clause sits slightly apart from the primary function.

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, no output schema, and safety covered by annotations, the description correctly compensates by describing what the tool returns (plan state plus an upgrade/cancel link). It is essentially complete for a simple zero-arg status tool, lacking only explicit routing guidance to siblings.

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 there is nothing for the description to disambiguate; the 4 baseline applies. Nothing in the description misrepresents the empty argument list.

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 verb and resource: it shows the user's Camberstack plan (free applied-changes remaining vs. Pro). That resource is clearly distinct from siblings like account_overview or run_gaql, though it does not explicitly name an alternative to compare against.

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 (check plan status to decide on upgrading), and the line that diagnosis, proposals, history and undo are always free implicitly tells the agent it does not need billing to gate those features. There is no explicit when-to-use or when-not guidance naming alternatives.

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