fetch_url

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

The description indicates read behavior ('fetches') and content type auto-detection, but lacks details on safety (e.g., no explicit read-only declaration), error handling, rate limits, or side effects. Since annotations are absent, the description should cover more behavioral traits.

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?

Two sentences, highly concise, no redundant information. The core purpose is front-loaded in the first sentence.

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?

The tool has no output schema, so the description should explain return values or behavior. It only says 'fetches and processes content' without specifying output format, pagination, or error scenarios. Incomplete for a context with 4 parameters and no 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 coverage is 100% with clear parameter descriptions. The tool description adds minimal new meaning beyond the schema (e.g., 'auto-detects content type' is relevant to raw parameter but not explicit). 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 clearly states 'fetches and processes content from any URL' and mentions auto-detection of content types. However, it does not explicitly differentiate from siblings like search_web or view_website, which could also involve URL fetching.

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 on when to use this tool versus alternatives. The description labels it as 'universal' but does not specify contexts where search_web or view_website would be more appropriate.

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