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

Annotations already declare readOnly, idempotent, and closed-world, so the safety profile is covered. The description still adds real value by disclosing the billing behavior ('No credit cost') and the authentication requirement ('Requires signing in with LLMready Pro'), neither of which is in the annotations.

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 short sentences, front-loaded with the outcome and followed by the two operational caveats. There is no filler and nothing a reader would need to skip past.

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-param read tool with no output schema, the description conveys what is reported (used and remaining credits, monthly window) plus the auth and cost conditions. A hint about the return shape (e.g. a numeric breakdown) would close the last gap, but no critical calling information 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, so there is nothing for the description to disambiguate; the baseline applies. Nothing in the description misrepresents the (empty) input surface.

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 gives a specific verb ('Show') and resource ('LLMready credits used and left this month'), and the scope ('this month') makes it trivially distinguishable from the sibling audit/generation tools. An agent can tell immediately that this is a quota/usage lookup, not an audit action.

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?

'No credit cost. Requires signing in with LLMready Pro.' gives clear invocation conditions and a prerequisite the agent would otherwise not know. It stops short of naming when-not-to-use or pointing at an alternative, but no sibling tool overlaps this function, so the exclusion set is naturally empty.

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