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

Annotations already establish that this is a safe, closed-world read, so the description's job is to add meaning — and it does, by clarifying that the connection's spend limit is a distinct concept from account credits and that billing/plan links are surfaced. It omits any mention of freshness or caching of credit figures, which is the only notable gap for a balance-style read.

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, front-loaded with the payload contents, with the operational advice ('check it before a render') placed last where it belongs. No filler or restatement of the title.

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?

There is no output schema, so the description carries the burden of describing return values — and it enumerates them (plan, credits, spend limit, billing links). Combined with the read-only annotations, an agent has everything needed to decide to call it and interpret the result.

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, which is the baseline-4 case: there is nothing for the description to disambiguate, and the schema is trivially complete.

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 opens with a specific verb ('Show') and enumerates exactly what the account resource returns: subscription plan, remaining credits, the connection's spend safety limit, and billing links. That content profile clearly separates it from siblings like estimate_cost or get_product without needing to name them.

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 for use: 'Check it before a render if credits may be short.' That is clear contextual guidance, but no when-not conditions and no named alternative (e.g. estimate_cost for a cost preview) are offered.

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