ga4_acquisition

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

With no annotations, the description carries the full burden and does disclose the two real blockers: the Analytics Data API must be enabled on the quota project and the caller needs Viewer access on the GA4 property. It also promises a self-explanatory access error and points to ga4_check_access. It does not state that the call is read-only, how rows are ordered or truncated by limit, or what the response looks like for a tool with no output 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?

Three tight clauses with the payload description front-loaded, then prerequisites, then the failure path. No filler. Minor deduction for the mid-sentence language switch to Spanish ("Lector (Viewer) en la propiedad de GA4") which slightly breaks readability in an otherwise English definition.

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 5-parameter reporting tool with no output schema, the definition covers purpose, prerequisites, error recovery and the metric set, which is most of what an agent needs. The remaining gaps are row-limiting behavior and the shape of the returned breakdown, neither of which is documented here or in an output schema.

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 80%, so the baseline is 3 and the schema already documents dates, property and the level enum. The description echoes source/medium/campaign but omits the fourth enum value (channel) and adds nothing about limit or the level-to-column mapping, so it contributes little meaning beyond the schema. It also does not explain the "first-user" vs session-level distinction that the level choice implies.

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?

"Where new users come from: first-user source, medium and campaign, with new users, active users and key events" names the resource (traffic acquisition) and the exact dimensions/metrics returned, so an agent can tell it apart from ga4_run_report or ga4_active_users. It is descriptive rather than verb-led, but the scope is 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?

It states the case this serves (new-user acquisition breakdown) and routes the agent elsewhere for setup problems by naming ga4_check_access as the one-shot health check. Prerequisite conditions are given explicitly. It stops short of naming sibling alternatives for overlapping report needs such as ga4_run_report or ga4_compare_periods.

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