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

Annotations are all false (no read-only, idempotent, or destructive hints), so the description carries the full burden of behavioral disclosure. It does this well by detailing the async extraction: name may initially be the bare domain, image_url may be null, and meta_extraction_progress < 100. It also warns against PATCHing the name unless a custom title is wanted. This goes beyond the schema and annotations, though it does not mention any other side effects or response details.

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 three sentences, front-loaded with the core purpose, and every sentence earns its place. It conveys the required field, the async extraction behavior, and a critical usage warning without any fluff or repetition. It is highly efficient and well-structured.

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?

There is no output schema, so the description must compensate for explaining the response. It does so partially by mentioning the fields that may be incomplete (name, image_url) and the meta_extraction_progress indicator. For a creation tool, this gives enough context for an agent to know what to expect. It could be more explicit about the full response structure (e.g., link ID), but given the async behavior is the main nuance, it is fairly 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 baseline is 3. The description adds value by explaining that url is the only required field and that name and image are extracted automatically from the page. It also clarifies the meaning of the name parameter (custom title vs. auto-extracted) and the async behavior tied to name and image_url. This enriches the parameter semantics beyond the raw schema.

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: 'Turn a product or brand URL into a Split link.' This clearly distinguishes it from sibling tools like split_create_links_bulk (bulk creation) and split_update_link (updating). It also states the key requirement (url is required) and the automatic extraction behavior, leaving no ambiguity about what the tool does.

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 explains the creation context and the async extraction behavior, and it warns against PATCHing the name prematurely. However, it does not explicitly compare this tool to alternatives like split_create_links_bulk or split_update_link, nor does it state when to prefer one over the other. The guidance is implied rather than explicit, so it falls short of a 4.

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