Create X Pixel (web event tag)

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

Annotations already indicate readOnlyHint=false (mutation) and openWorldHint=true (creates new entities). The description aligns with these by stating 'Create' and adds useful behavior: default values for type and retargeting_enabled, valid window values, and the return of embed_code and website_tag_id. However, it does not disclose side effects, permission requirements, or behavior on duplicate names, which would be valuable given the low annotation detail.

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 extremely concise—a single sentence that front-loads the purpose and packs essential parameter defaults and return values. Every clause adds information, with no filler or repetition.

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?

Given the low schema coverage and no output schema, the description covers the key parameters, defaults, and return values. It omits details like idempotency, failure modes, or permission prerequisites, but for a straightforward create operation with clear siblings, it is nearly complete for an agent to call it correctly.

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 only 17%, so the description carries most of the parameter meaning. It explicitly states the default for type (SITE_VISIT), the allowed days for click_window and view_through_window (0,1,7,14,30,60,90), the default for retargeting_enabled (false), and advises not to invent names for the name parameter. This significantly compensates for the sparse 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 states 'Create a conversion / site-visit web event tag' with a clear verb and resource, and the name 'x_ads_create_pixel' distinguishes it from siblings like x_ads_get_pixel, x_ads_list_pixels, x_ads_update_pixel, and x_ads_delete_pixel. It is unambiguous what this 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 provides no guidance on when to use this tool versus alternatives. It does not mention that this is for creating a new pixel while x_ads_update_pixel is for modifying an existing one, nor does it discuss when not to use it. The only usage hint is 'Don't invent names,' which is a parameter constraint rather than usage context.

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