multi_fetch

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 does explain that fetching is parallel, returns Markdown, and caps at 5 URLs. However, it does not disclose what happens on partial failures, per-URL errors, malformed URLs, or whether results are returned in the original order, which is meaningful for a batch fetch tool.

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 with no filler. The first sentence states the core action and output format, and the second provides use cases and the limit. Every sentence earns its place.

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 batch-fetch tool with only one required parameter and complete schema descriptions, the description covers the essential selection and invocation information well. The main gap is the lack of explicit failure/partial-response behavior, and since there is no output schema, a bit more detail about return behavior would make it fully complete.

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 input schema already documents all four parameters. The description adds only the max-5 constraint, which the schema also states, and provides no additional meaning for timeout, wait_for, or max_length_per_page. This aligns with the baseline of 3.

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 the action ('Fetch multiple URLs in parallel') and the resource ('multiple URLs'), and identifies the output ('return their content as Markdown'). It also distinguishes itself from sibling tools like fetch_page by emphasizing parallel batch fetching, making its purpose 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 concrete use cases: 'comparing sources or gathering information from several pages at once,' which tells an agent when this tool is appropriate. It does not explicitly name alternatives like fetch_page or crawl, nor does it state when not to use it, so it falls short of a 5.

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