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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context beyond that: credits are consumed one per production, which tells the agent this value is a depleting resource. It stops short of disclosing the return shape or what happens at zero credits.

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 clauses, no filler, with the resource definition front-loaded and the boundary condition second. Every sentence earns its place.

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 no-argument read-only query with annotations covering safety, the description supplies purpose plus the consumption semantics an agent needs to interpret the result. The only gap is the return format (a count? a breakdown?) with no output schema to fill it in.

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 and has 100% schema coverage, so there is nothing for the description to disambiguate. Baseline 4 applies; no parameter-related information is missing or contradicted.

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 names the resource (existing order credits remaining) and adds the consumption rule (each new production uses one), which no sibling tool covers. It's stated as a noun fragment rather than an explicit verb ('returns the number of...'), so it falls just short of a 5, but an agent can immediately tell this is the credits-balance query.

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?

The second sentence provides a real exclusion boundary — 'does not sell credits or initiate purchases' — steering the agent away from using this as a purchase tool. However, it never states positively when to call it (e.g. before create_production) or what alternative to use for purchases, so guidance is implied rather than explicit.

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