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

With no annotations provided, the description carries the full burden of behavioral disclosure. It successfully indicates the output format (Markdown conversion), but fails to disclose safety characteristics (read-only vs. destructive), error handling behavior for invalid URLs, content size limits, or whether network redirects are followed.

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 a single, front-loaded sentence with zero redundancy. Every word earns its place: action ('Fetch and extract'), subject ('article content'), input ('from a URL'), and output format ('formatted as Markdown') are all essential.

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?

Given the absence of an output schema, the description partially compensates by specifying Markdown formatting. However, for a web-fetching tool with no annotations, it omits important context: error scenarios (404, timeouts), content type restrictions, rate limiting, and return structure beyond format type.

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 description coverage is 0%, requiring the description to compensate. The phrase 'from a URL' implies the purpose of the 'url' parameter, but lacks explicit documentation of what the URL should point to (article) or validation requirements. It provides just enough context to infer meaning given the single parameter.

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 uses specific verbs ('Fetch and extract'), identifies the resource ('article content'), specifies the input source ('from a URL'), and distinguishes output format ('formatted as Markdown'). This clearly differentiates it from sibling 'fetch_feed_entries' by emphasizing single-article extraction vs. feed aggregation.

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?

The description provides no guidance on when to use this tool versus alternatives, nor does it mention the sibling 'fetch_feed_entries'. There are no prerequisites stated (e.g., valid URL requirements) or exclusion criteria.

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