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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false, and the description adds meaningful policy beyond that: this is a pre-creation gate and calls should halt once a cap is hit. It doesn't clarify what 'stop' concretely means (abort vs. report) or how cap breaches surface, keeping it just short of 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?

The behavioral rule is front-loaded ('Call this before creating anything'), followed by a compact field enumeration and a stop condition. The inline comma list of ten fields is dense but each entry carries information given there is no output schema.

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 enumeration of returned fields is exactly the return contract an agent needs, and workspace scoping plus the pre-creation gate are stated. What's missing is only edge behavior (what a cap breach looks like, units for min_interval_seconds) — minor for a zero-parameter read tool.

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; there is nothing for the description to compensate for. The field list is about return values rather than inputs, which does not detract from this dimension.

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 description names the resource (plan caps for this workspace) and enumerates exactly which caps are reported (probe_count, monthly_probe_quota, max_endpoints, etc.), so an agent knows this is a read-only quota/usage lookup. The tool name 'usage' alone is vague, but the description disambiguates it and clearly distinguishes it from the create_*/list_* siblings.

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?

'Call this before creating anything' gives an explicit pre-flight trigger, and 'Stop when a cap is reached' defines a stopping condition. It doesn't name a specific alternative tool, but the sibling set of create_* tools makes the intended sequencing obvious.

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