Article or PDF URL to clean Markdown

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 thoroughly describes what the tool does under the hood (Firefox reader-mode extraction, text extraction for PDFs), what it refuses (private/loopback/cloud-metadata addresses), what it returns (title, byline, excerpt, word count, truncation flag), and the cost/payment mechanism. This is exemplary transparency.

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 two sentences, front-loaded with the core action, and packs in critical information like limitations, error handling, security restrictions, and pricing without any fluff. Every clause earns its place, and the structure flows logically from purpose to behavior to constraints.

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?

Despite having no output schema and no annotations, the description covers all essential contextual information: input type, extraction method, edge cases (client-rendered pages), security guards, return fields, and cost. For a tool with a single parameter, this is fully self-contained and leaves the agent well-equipped to select and invoke it 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 input schema has 100% description coverage for the single 'url' parameter, stating 'Public http/https URL of an article or PDF.' The description adds some context about address restrictions and extraction behavior, but it doesn't significantly extend the parameter's meaning beyond what the schema already provides. Baseline 3 is appropriate.

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 opens with a specific verb and resource: 'Fetch a public article or PDF URL and return clean Markdown.' It clearly distinguishes from siblings like geocode/weather by focusing on URL-to-Markdown conversion. It also specifies two extraction modes (reader-mode for HTML, text extraction for PDFs), making the intended functionality unambiguous.

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 clear context: it's for public articles/PDFs, and explicitly notes that JavaScript is not executed, so client-rendered pages will return an error. It also lists restrictions (private, loopback, cloud-metadata addresses refused). While it doesn't name alternative tools, the sibling set is unrelated, so no additional when-to-use guidance is necessary.

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