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

Annotations already cover read-only/idempotent/non-destructive, so the description earns credit for adding real context: a per-crawler-family daily allowance of 1,000 reads with 429 on overage, billing being disabled, and no X-API-Pass required. This is meaningful behavioral detail beyond the annotations.

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?

Six dense sentences mixing purpose, crawler rate limits, billing state and index scope; the core 'what does this return' statement is buried and diluted. Informative but not front-loaded or tight for a single-parameter status tool.

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 should clarify what the status call returns, but it never states the response shape. Quotas, billing state and scope are covered adequately, leaving the return-value gap for a tool an agent must call to check access.

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 schema already documents api_pass format and its 'generate before buying' note. The description adds only tangential context ('pass prefix mat_', 'reads need no X-API-Pass'), so the baseline 3 applies since the schema carries the parameter semantics.

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 opening says it reports 'monthly data package and private purchase status' and a 'MAT-only balance,' which hints at a status/balance read, but the phrasing is muddled and never states a clean verb+resource. It distinguishes scope (MAT-only, separate from other indexes) but not from siblings like api_usage or api_access_buy.

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 explicit when-to-use or when-not-to-use guidance. The line 'there is no package to buy' faintly implies api_access_buy is not applicable, and 'reads need no X-API-Pass' implies the pass may be omitted, but neither is framed as routing advice.

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