Check balance and quota

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

Annotations already declare a safe read, and the description adds real behavior beyond them: the call spends no query admission units and creates no provider job, and missing provider balances are reported as unknown rather than zero. Those are exactly the kind of side-effect and semantics details an agent cannot infer from the structured fields.

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?

Four compact sentences, front-loaded with what is returned, followed by side-effect and semantics caveats. Each sentence carries distinct information, though the installation-scope sentence could arguably be trimmed.

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?

Given zero parameters and an existing annotation set, the description covers what is measured, that no units/jobs are consumed, and the unknown-vs-zero caveat. It does not describe the response shape, but the tool is simple enough that the remaining gap is minor.

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, so the baseline is 4; the schema is trivially exhaustive and there is nothing parameter-wise for the description to compensate for. It adds no parameter meaning because none exists to describe.

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 verb (Check) plus the exact resources: the installation's remaining MCP allowance across rolling hour/day/30-day windows, and linked-account provider credits with freshness. This is clearly distinct from every sibling, which are all report-generation or lookup tools.

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 conveys when this is the right call (introspecting your own allowance/credits) and clarifies the scope caveat that allowances are per-installation and differ across installations. There is no sibling that competes for this purpose, so no explicit alternative needs naming, but it stops short of an explicit 'call this before heavy queries' routing statement.

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