usage

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

With no annotations supplied, the description carries the full disclosure burden and does well: it explains that locked modes (grok Expert/Heavy on a lapsed sub) read 0/0, which is genuine interpretation guidance for the output rather than a restatement of the name. It also distinguishes the richer logged-in-session payload (live per-tier limits, model/mode catalog, thinking levels) from the basic snapshot. It omits auth prerequisites and whether calling it has any cost.

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?

Purpose and default behavior are front-loaded in the first clause, and the optional-parameter expansion follows in a clearly conditional second sentence. The em-dash-heavy phrasing and jargon like 'escape-hatch `mode` values' cost a little readability but no sentence is filler.

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 single-optional-parameter, read-oriented introspection tool with no annotations and no output schema, the description does the heavy lifting: it describes both return shapes and how to interpret a degenerate 0/0 result. Only ancillary facts an agent might want — auth state, whether quota numbers are cached or live — are absent.

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 already 100%, so the baseline would be 3, but the description goes further by unpacking what the `provider` value actually yields — niches, escape-hatch `mode` values, and ready-to-copy example calls — and by giving a concrete example (grok Expert/Heavy on a lapsed sub) that maps the enum to observable behavior.

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?

Names a specific verb and resource ('Show remaining free quota per account and provider for the current period') and then enumerates the exact contents of the response, including assigned proxies and per-tier limits. The scope is unambiguous and cannot be confused with any sibling tool (browser, read, search, create_image, deep_research).

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?

Explicitly tells the agent how to choose between the two invocation modes: pass `provider` for that backend's full capability sheet, omit it for the compact all-provider snapshot. What is missing is any guidance on when this tool is not appropriate or what to do if a provider isn't configured.

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