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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so the safety profile is covered. The description adds genuine behavioral context beyond that: null means no cap, monthlyCapUsedCad is tracked in Montreal time, and once the cap is reached no automatic reload occurs until the next month. It stops short of describing the response shape or formatting, so not a 5.

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?

Front-loaded with the core purpose and dense with signal, but the single run-on sentence with heavily nested parentheticals makes it harder to parse than it needs to be. Every clause carries information, so little is wasted.

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 must carry the return-value burden, and it does — enumerating the cap, usage, and remaining/limit-reached fields. It also discloses the required billing:read permission and free-account prerequisite, leaving nothing an agent needs in order to call it correctly.

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 schema imposes no semantic burden and the baseline is 4. The description instead clarifies the meaning of returned fields (null = no cap, timezone semantics), which is valuable though technically output rather than parameter semantics.

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?

States a specific resource (automatic credit reload settings) and enumerates exactly what is returned: threshold, amount charged to the saved card, and the monthly cap fields. An agent can distinguish this read-only getter from the sibling gpucloud_set_auto_reload without opening the schema.

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 by the getter/setter pairing with gpucloud_set_auto_reload, but the description never explicitly states when to call this versus alternatives, nor any exclusions. The permission/account prerequisites are given, but routing guidance is left to inference.

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