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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. With no output schema, the description's enumeration of return contents (free words, expiry, claimed/paid) is genuinely useful, but it says nothing about authentication requirements, freshness, or whether the trial state can change between calls.

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?

A single compact clause with zero padding, and the most decision-relevant information (free words left) is front-loaded. It is a verbless fragment rather than a sentence, which slightly weakens framing but costs nothing in length.

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 one-parameter read tool with full schema coverage and annotations covering safety, the description supplies the missing piece — what the call returns — since no output schema exists. It stops short of explaining token provenance or when the reported trial state is meaningful.

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 single agent_token parameter is documented in the schema as coming from proxylang_start. The description adds no parameter meaning beyond that, so the baseline 3 applies.

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 specific data the tool reports — free words remaining, trial expiry, and claimed/paid status — so an agent knows it is a trial/quota status reader. However, it uses no verb and does not differentiate itself from siblings like proxylang_check or proxylang_next, which an agent might plausibly confuse it with.

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?

There is no when-to-use statement, no precondition, and no mention of alternatives among the sibling tools. Usage (call it to learn remaining quota) is only inferable from the list of returned fields, and the description gives no guidance about when this is preferable to proxylang_check.

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