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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered; the description usefully adds that only credits with a nonzero balance are returned. It says nothing about whether already-expired credits are included or how the window is bounded.

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?

One short sentence with no filler, and the key qualifier (expiring within N days) comes at the end where it reads naturally. It is under-specified rather than padded.

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?

An output schema exists, so return shape needn't be described, and annotations cover safety. Gaps remain on window semantics and on routing among the many reporting siblings, which matters for a tool with 12 dashboard-style alternatives.

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?

Schema coverage is 0%, so the description must carry the parameter's meaning; it does clarify that within_days is an expiry horizon in days, which is real added value. It does not state the reference point (now vs. billing cycle), inclusivity, or that the field is optional with a 60-day default.

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 phrase names a specific resource (provider credits), a filter (positive balance), and a time horizon, which distinguishes it from siblings like get_spend or get_account. It is a noun fragment without a verb, but the returned entity is unambiguous.

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 says nothing about when to reach for this tool versus get_spend, get_customer_cost, or reconciliation_status. The only usage signal is the implied 'set within_days to your horizon', which an agent must infer.

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