willys_fetch_url

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

With no annotations provided, the description carries the full burden. It discloses the mechanism (via user's home IP), the benefits (bypasses blocks, cheaper), the fallback behavior, and automatic JS rendering. This goes beyond a simple fetch description and prepares the agent for expected behavior.

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?

Four sentences, each adding value: purpose, when to use, fallback, and rendering behavior. Front-loaded with the core action, no redundancy or 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 simple 2-parameter tool, the description covers the purpose, output format, usage priority, fallback, and rendering behavior. It is clear what the tool does and what to expect in return, making it complete without an output schema.

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 100%, so the baseline is 3. The description reinforces the 'render' parameter's auto-escalation behavior, but overall adds limited new meaning beyond what the schema already provides.

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 clearly states it fetches a webpage from the user's computer and returns structured data (JSON-LD) plus clean text. This is a specific verb+resource with a clear output, distinguishing it from sibling tools that are all grocery-related.

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?

Explicitly instructs to run this FIRST when reading a URL, and to fall back to own browsing only if this fails. Also explains the advantages (bypasses blocks, cheaper), giving clear context for when to use this tool over alternatives.

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