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

The annotations already declare this is a non-read-only, non-destructive, non-idempotent create operation. Beyond that, the description adds the account pixel-limit constraint and states the exact return value, the <img> tag, which is valuable because no output schema exists.

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 short sentences, front-loaded with the action and followed by the practical result. There is no redundant or filler wording.

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 one-parameter create tool with annotations and no output schema, the description covers purpose, the account limit, and the returned embed tag. It leaves out failure behavior when the limit is exceeded and does not mention permissions, but the core information needed to call it is present.

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?

There is one parameter, name, and the schema already describes it as 'Pixel name' with 100% coverage. The description does not add any further meaning about naming rules, uniqueness, or formatting, so the schema does the work here.

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 states a specific verb and resource: 'Make a tracking pixel.' It clearly implies creation rather than retrieval or deletion, but it does not explicitly distinguish this tool from siblings such as get_pixel, list_pixels, or delete_pixel.

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?

It says what the tool creates and that the result is an <img> tag to paste into a page or email, but gives no explicit when-to-use or when-not-to-use guidance. It also does not route the agent to alternatives such as get_pixel, list_pixels, or delete_pixel.

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