Cromanion

cromanion_set_holdout

DestructiveIdempotent

Set the share of visitors held back from the agent so its effect stays measurable (0.05–0.5). Changing it splits the measurement window: periods either side are compared separately and never pooled. Needs the measurement permission.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`share`	Yes	Fraction held back, e.g. 0.1 for 10%.
`siteId`	No	Which site this call is about. Only needed when your credential covers more than one — cromanion_grants lists them and says whether it is required. Omitting it with several is refused rather than guessed at.

Output Schema

TableJSON Schema

Name	Required	Description
`ok`	Yes
`note`	No	That this change split the measurement window, and what that means for later comparisons.
`holdoutShare`	Yes	The share as APPLIED, clamped to 0.05–0.5. Read it rather than assuming your value was taken verbatim.

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

Changed1 schema field changedSep 7, 2026

addedInput schema / properties / siteId

Added value: +{
+  "description": "Which site this call is about. Only needed when your credential covers more than one — cromanion_grants lists them and says whether it is required. Omitting it with several is refused rather than guessed at.",
+  "type": "string"
+}

Changed1 schema field changedSep 6, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "holdoutShare": {
+      "description": "The share as APPLIED, clamped to 0.05–0.5. Read it rather than assuming your value was taken verbatim.",
+      "type": "number"
+    },
+    "note": {
+      "description": "That this change split the measurement window, and what that means for later comparisons.",
+      "type": "string"
+    },
+    "ok": {
+      "type": "boolean"
+    }
+  },
+  "required": [
+    "ok",
+    "holdoutShare"
+  ],
+  "type": "object"
+}

First observedSep 6, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Annotations already indicate destructive and idempotent behavior; the description adds meaningful context about splitting the measurement window and never pooling periods. It does not repeat the destructive hint, but the annotations cover that risk.

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

Conciseness5/5

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

Three concise sentences, no filler, with the primary action and key constraints stated upfront.

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

Completeness5/5

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

Includes the required permission, the quantitative range, the behavioral implication of changing the value, and references an output schema exists. No critical information needed to invoke the tool is missing.

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

Parameters3/5

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

Schema covers 100% of parameters with clear descriptions; the tool description adds context about the allowed range and the measurement-window effect, but does not substantially deepen parameter-specific meaning beyond the 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 ('Set'), the resource ('share of visitors held back'), and the purpose ('so its effect stays measurable'), clearly distinguishing it from siblings.

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

Usage Guidelines4/5

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

Provides clear context about when this tool is relevant, including the required permission ('Needs the measurement permission') and the behavioral consequence of changing the holdout share. It does not explicitly contrast with alternatives, but the context is sufficient.

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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