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

With no annotations, the description carries the full burden, and it does disclose the useful behavioral detail that output is truncated (20k chars text, 40k Markdown) and that only 'main article' content is returned. It omits failure modes, paywall/JS-rendering limitations, and whether the fetch is cached or rate-limited.

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?

One sentence, front-loaded with the verb and resource, with the field list and size caps appended efficiently. No filler.

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 no output schema, enumerating the returned fields and their truncation limits is genuinely sufficient. The only material gap is what happens when extraction fails or the page is not an article.

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?

There is a single required parameter with 100% schema description coverage ('HTTP(S) URL of the article page'), so the baseline is 3. The description's phrase 'web page URL' adds no syntax, normalization, or redirect handling detail beyond the schema.

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?

States a specific verb ('Extract') and resource ('main article text and Markdown from a web page URL'), and enumerates the returned fields, so the agent knows exactly what it gets. It never mentions the sibling fetch_feed, so the article-vs-feed distinction must be inferred from the names.

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 only implied: 'from a web page URL' plus 'main article text' suggests single-page content extraction with boilerplate removal. There is no explicit when-to-use, no exclusion (e.g. non-article pages, JS-rendered pages), and no routing to fetch_feed as the alternative.

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