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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description contributes the quota context — that figures are per API key and reset periodically — but says nothing about the response shape or whether 'used' and 'left' are returned as a total or per-period.

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 sentence carries the whole definition, front-loading the metrics (pages used, pages left) before the reset detail. Nothing is padded, though the phrasing is slightly compressed.

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 description must hint at return values, and it does: pages used, pages remaining, and the reset time. For a zero-parameter, read-only quota check, this is nearly everything an agent needs to decide to call it.

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 of 4 applies. The description correctly signals that no inputs are required by framing the result as scoped to 'the DocFig API key'.

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 states a specific resource (pages used/left this month) and adds scope details — per DocFig API key and the reset timing — that the brief title alone does not. That makes it clearly distinct from the unrelated siblings (check_transactions, combine_statements, convert_statement).

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?

Usage is implied: an agent would call this to check remaining quota before hitting limits. However there is no explicit when-to-use statement, no mention of what to do when pages run out, and no named alternative — though none of the siblings are alternatives here.

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