Registers an event or user parameter as a custom dimension in Google Analytics 4, making that data available for reporting.
Register an event or user parameter as a custom dimension so it can be used in reports.
| Name | Required | Description | Default |
|---|---|---|---|
| scope | No | EVENT | |
| confirm | No | ||
| description | No | ||
| property_id | Yes | ||
| display_name | Yes | ||
| parameter_name | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and openWorldHint=true, so the bar is lower, yet the description adds nothing about the notable behaviors: the `confirm` flag (default false) that almost certainly gates the actual write, GA4's per-property custom-dimension cardinality limits, and the auth/PHP scope needed. None of these are disclosed, leaving the agent to discover the confirmation flow only from the schema.
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?
One front-loaded sentence with zero filler; the purpose and its payoff are packed into a single clause. Nothing is redundant.
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 destructive, open-world mutation with six undocumented parameters and a confirmation gate, one sentence is not sufficient. An output schema exists so return values needn't be covered, but the write semantics, confirmation requirement, and quota implications are all missing.
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 0% with six parameters, so the description carries the full burden and delivers almost nothing. "event or user parameter" loosely gestures at `scope`/`parameter_name`, but `confirm`, `description`, and `property_id` — including how the required property ID is obtained — are completely unexplained.
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?
States a specific verb+resource ("Register ... as a custom dimension") and the downstream effect ("used in reports"), which is far clearer than the name alone. It does not explicitly contrast with the nearest sibling, ga4_create_key_event, but the resource noun is distinctive enough that an agent can separate them.
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 phrase "so it can be used in reports" implies why an agent would call it, but there is no explicit when/when-not guidance, no stated prerequisite (the parameter must already be collected in the property), and no reference to alternatives. Usage must be inferred.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.