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Create Incrementality Test

create_incrementality_test

Record an incrementality test in a project, including design, dates, KPI, result, and spend, to calibrate a model activity column.

Instructions

Record one incrementality test in a project, as analysed in its own tool: its design (geo, owned_media_ab or platform_lift block), dates, KPI, result with interval or sd, and incremental spend. Returns {id, version: 1, record, content_hash}. Set model_channel to the model activity column the test calibrates so it can be used with a model. Validation errors name the field (e.g. "the interval must contain lift_abs"). Not idempotent: calling twice records two tests. type time_holdout is not accepted here: planned time-holdout records are created only through save_incrementality_test_design (the backend refuses them elsewhere), and a status planned record of any type carries no result. Requires the create:models scope.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`record`	Yes	One incrementality test as analysed in its own tool (Simba fits nothing here). type picks the design block: geo, owned_media_ab or platform_lift. Dates are YYYY-MM-DD; measured_through is the end of the carryover window (default end_date). result.lift_abs is the total lift in KPI units over the window; give its interval (two-sided, level e.g. 0.9) and/or sd. Null and negative lifts are valid. spend.incremental is the extra spend the test caused (signed). The time_holdout type and block appear on records the server builds from a test-design calculation (save_incrementality_test_design); they are read and listed here but not accepted on create or import, and a status planned record carries no result.
`project_id`	Yes

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedv0.17.0Oct 4, 2026

changedInput schema / properties / record / description

Previous value: -"One incrementality test as analysed in its own tool (Simba fits nothing here). type picks the design block: geo, owned_media_ab or platform_lift. Dates are YYYY-MM-DD; measured_through is the end of the carryover window (default end_date). result.lift_abs is the total lift in KPI units over the window; give its interval (two-sided, level e.g. 0.9) and/or sd. Null and negative lifts are valid. spend.incremental is the extra spend the test caused (signed)."New value: +"One incrementality test as analysed in its own tool (Simba fits nothing here). type picks the design block: geo, owned_media_ab or platform_lift. Dates are YYYY-MM-DD; measured_through is the end of the carryover window (default end_date). result.lift_abs is the total lift in KPI units over the window; give its interval (two-sided, level e.g. 0.9) and/or sd. Null and negative lifts are valid. spend.incremental is the extra spend the test caused (signed). The time_holdout type and block appear on records the server builds from a test-design calculation (save_incrementality_test_design); they are read and listed here but not accepted on create or import, and a status planned record carries no result."

addedInput schema / properties / record / properties / time_holdout

Added value: +{
+  "description": "Server-built from a test design: the outcome in the holdout window is contrasted with the model's forecast.",
+  "properties": {
+    "analysis_method": {
+      "type": "string"
+    },
+    "carryover_periods": {
+      "minimum": 0,
+      "type": "integer"
+    },
+    "counterfactual": {
+      "enum": [
+        "model_forecast"
+      ],
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

changedInput schema / properties / record / properties / type / enum

Previous value: -[
-  "geo",
-  "owned_media_ab",
-  "platform_lift"
-]New value: +[
+  "geo",
+  "owned_media_ab",
+  "platform_lift",
+  "time_holdout"
+]

Addedv0.12.0Sep 30, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Goes beyond annotations by naming the required auth scope, describing validation error behavior ('name the field'), and spelling out the consequence of non-idempotency ('calling twice records two tests', consistent with idempotentHint=false). It also notes that planned records carry no result. These add real behavioral context beyond the safety annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the primary action and record contents, then progressively adds return shape, validation, idempotency, exclusion and scope. Dense but every clause carries information; only slight redundancy with annotations on idempotency.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a complex nested-schema mutation with an output schema present, the description covers the design-block semantics, validation, scope, and the excluded time_holdout path. Return values are documented by the output schema, so omitting them is fine; a few minor behaviors (e.g. limits on record size) are not addressed but not critical.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is only 50%, so the description must compensate, and it does: it explains what type selects (geo/owned_media_ab/platform_lift block), that dates are YYYY-MM-DD, that measured_through defaults to end_date, that lift_abs is total lift in KPI units, that null/negative lifts are valid, and that spend.incremental is signed. This meaningfully supplements the nested schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource ('Record one incrementality test in a project') and immediately scopes what a record contains (design block, dates, KPI, result, spend). It also names a sibling it is NOT: 'type time_holdout is not accepted here... created only through save_incrementality_test_design', letting an agent distinguish it from nearby tools without opening schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit when-not guidance: time_holdout is refused here and must go through save_incrementality_test_design. It also states the required scope ('create:models') and the setup condition ('Set model_channel to the model activity column the test calibrates'). No alternatives are left to inference.

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

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