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

With no annotations, the description carries the full burden. It discloses only the cost behavior ('0 units on hit') but fails to explain what happens on a cache miss, what the actual output format is, or whether any side effects or rate limits apply. The term 'extract' itself is undefined.

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 description is extremely short (six words) and front-loaded, but it is under-specified rather than efficiently concise. It omits critical details about the tool's core behavior, making the brevity a drawback rather than a strength.

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 tool with only one parameter and no output schema, the description still fails to explain its fundamental purpose, expected return value, or relationship to the many sibling tools. The mention of caching and cost is useful but insufficient for an agent to select and invoke the tool correctly.

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 schema has one parameter 'url' with no description (0% coverage). The description does not mention the parameter at all. While the parameter name is self-explanatory from the tool name, the description adds no semantic value beyond what the schema's field name already implies.

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 'Cached extract' indicates the tool performs an extraction operation on a URL with caching, but 'extract' is vague and does not specify what is being extracted (HTML, text, links, etc.). It does not distinguish itself from the many other extract-* sibling tools.

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?

No guidance is provided on when to use this tool versus alternatives like extract_links, extract_pdf, or read_url. The description does not mention any context, prerequisites, or exclusionary conditions.

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