get_usage

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

With no annotations, the description carries the full burden and does so well: it discloses that the call is free, explains the two auth modes and their different payloads, and mentions the retryAfterSeconds context after a 429. It does not describe pagination or bounds on the 'last calls' ledger, keeping it below 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?

The description is a single dense paragraph that is front-loaded with purpose, then mode-specific return details, then usage guidance. Every sentence earns its place, though the density and parenthetical clauses make it slightly harder to scan than it could be.

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 dual-mode tool with no output schema and no annotations, the description is largely complete: it explains what each credential type returns and when to call it. Missing details such as how many recent calls are included in the ledger are minor but prevent a 5.

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 100%, and the schema already documents that since/until are agent-grant-only window bounds defaulting to 30 days back. The description mentions the 30-day view but adds no syntax or usage details beyond the schema, so baseline 3 is appropriate.

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 opening sentence states the resource precisely: remaining balance and spend for the current key. It then distinguishes the two credential modes (gateway key vs. agent grant) with concrete returned fields, so an agent knows exactly what this tool does.

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 explicit timing guidance: 'Read it before a burst and after a 429'. That covers the primary when-to-use contexts. It does not name alternatives or exclusions, but no sibling tool provides similar usage data, so the gap is minor.

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