Australian Accounting MCP

Generate a synthetic CTR or BAS fixture

generate_synthetic_sbr_fixture

Read-onlyIdempotent

Generate synthetic CTR or BAS SBR payloads to test agent integrations using fabricated data. Returns in-memory fixtures marked synthetic, with no lodgements or file writes.

Instructions

Generate fabricated CTR/BAS payloads for testing an agent integration.

revenue_or_sales is an AUD decimal string such as "1000.00": finite, at most 2 decimal places, absolute value at most 1000000000000.00. Use only with synthetic inputs. Fixed demonstration assumptions produce a payload marked synthetic=true and not_a_lodgment=true, not a real tax calculation or production SBR validation. Returns the fixture in memory; no file writes, network calls or lodgements. Not statutory advice.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`form_type`	Yes	Fixture type: "CTR" (company tax return) or "BAS" (activity statement), case-insensitive. No other forms are supported.
`entity_name`	No	Fabricated entity label for test output; defaults to "Synthetix Pty Ltd". Do not supply real client data.	Synthetix Pty Ltd
`revenue_or_sales`	No	Fabricated gross revenue (CTR) or total sales G1 (BAS); defaults to "1000000.00".Other figures use fixed demonstration assumptions.	1000000.00

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.1.22Oct 6, 2026
- addedInput schema / properties / revenue_or_sales / pattern
```
Added value: +"^\\s*-?[0-9]+(?:\\.[0-9]{1,2})?\\s*$"
```

Changed4 schema fields changedv0.1.13Sep 21, 2026

addedInput schema / properties / entity_name / maxLength
```
Added value: +120
```
addedInput schema / properties / form_type / maxLength
```
Added value: +20
```

changedInput schema / properties / revenue_or_sales / description

Previous value: -"Fabricated gross revenue (CTR) or total sales G1 (BAS); defaults to \"1000000.00\". Other figures use fixed demonstration assumptions. AUD decimal string, e.g. \"1000.00\"; finite, at most 2 decimal places, absolute value at most 1000000000000.00."New value: +"Fabricated gross revenue (CTR) or total sales G1 (BAS); defaults to \"1000000.00\".Other figures use fixed demonstration assumptions."

addedInput schema / properties / revenue_or_sales / maxLength
```
Added value: +60
```

Changed1 schema field changedv0.1.10Sep 10, 2026
- addedInput schema / additionalProperties
```
Added value: +false
```

Changed4 schema fields changedv0.1.8Sep 5, 2026

addedOutput schema / $defs

Added value: +{
+  "BasFixture": {
+    "additionalProperties": true,
+    "not": {
+      "anyOf": [
+        {
+          "required": [
+            "income_statement"
+          ]
+        },
+        {
+          "required": [
+            "reconciliation"
+          ]
+        }
+      ]
+    },
+    "properties": {
+      "entity": {
+        "additionalProperties": true,
+        "description": "Fabricated identity and period fields.",
+        "title": "Entity",
+        "type": "object"
+      },
+      "form_type": {
+        "const": "BAS_AU_ACTIVITY_STATEMENT",
+        "title": "Form Type",
+        "type": "string"
+      },
+      "gst_labels": {
+        "additionalProperties": {
+          "description": "Finite engine decimal string, including exponent notation; retain its precision.",
+          "pattern": "^[+-]?(?:[0-9]+(?:\\.[0-9]*)?|\\.[0-9]+)(?:[eE][+-]?[0-9]+)?$",
+          "type": "string"
+        },
+        "description": "Synthetic BAS GST labels.",
+        "title": "Gst Labels",
+        "type": "object"
+      },
+      "not_a_lodgment": {
+        "const": true,
+        "description": "Never a lodgment-ready payload.",
+        "title": "Not A Lodgment",
+        "type": "boolean"
+      },
+      "payg_withholding_labels": {
+        "additionalProperties": {
+          "description": "Finite engine decimal string, including exponent notation; retain its precision.",
+          "pattern": "^[+-]?(?:[0-9]+(?:\\.[0-9]*)?|\\.[0-9]+)(?:[eE][+-]?[0-9]+)?$",
+          "type": "string"
+        },
+        "description": "Synthetic BAS PAYG labels.",
+        "title": "Payg Withholding Labels",
+        "type": "object"
+      },
+      "summary": {
+        "additionalProperties": {
+          "description": "Finite engine decimal string, including exponent notation; retain its precision.",
+          "pattern": "^[+-]?(?:[0-9]+(?:\\.[0-9]*)?|\\.[0-9]+)(?:[eE][+-]?[0-9]+)?$",
+          "type": "string"
+        },
+        "description": "Synthetic BAS total.",
+        "title": "Summary",
+        "type": "object"
+      },
+      "synthetic": {
+        "const": true,
+        "description": "Fabricated test data; never real client results.",
+        "title": "Synthetic",
+        "type": "boolean"
+      }
+    },
+    "required": [
+      "synthetic",
+      "not_a_lodgment",
+      "entity",
+      "form_type",
+      "gst_labels",
+      "payg_withholding_labels",
+      "summary"
+    ],
+    "title": "BasFixture",
+    "type": "object"
+  },
+  "CtrFixture": {
+    "additionalProperties": true,
+    "not": {
+      "anyOf": [
+        {
+          "required": [
+            "gst_labels"
+          ]
+        },
+        {
+          "required": [
+            "payg_withholding_labels"
+          ]
+        },
+        {
+          "required": [
+            "summary"
+          ]
+        }
+      ]
+    },
+    "properties": {
+      "entity": {
+        "additionalProperties": true,
+        "description": "Fabricated identity and period fields.",
+        "title": "Entity",
+        "type": "object"
+      },
+      "form_type": {
+        "const": "CTR_AU_2025",
+        "title": "Form Type",
+        "type": "string"
+      },
+      "income_statement": {
+        "additionalProperties": {
+          "description": "Finite engine decimal string, including exponent notation; retain its precision.",
+          "pattern": "^[+-]?(?:[0-9]+(?:\\.[0-9]*)?|\\.[0-9]+)(?:[eE][+-]?[0-9]+)?$",
+          "type": "string"
+        },
+        "description": "Synthetic CTR income figures.",
+        "title": "Income Statement",
+        "type": "object"
+      },
+      "not_a_lodgment": {
+        "const": true,
+        "description": "Never a lodgment-ready payload.",
+        "title": "Not A Lodgment",
+        "type": "boolean"
+      },
+      "reconciliation": {
+        "additionalProperties": {
+          "description": "Finite engine decimal string, including exponent notation; retain its precision.",
+          "pattern": "^[+-]?(?:[0-9]+(?:\\.[0-9]*)?|\\.[0-9]+)(?:[eE][+-]?[0-9]+)?$",
+          "type": "string"
+        },
+        "description": "Synthetic CTR reconciliation.",
+        "title": "Reconciliation",
+        "type": "object"
+      },
+      "synthetic": {
+        "const": true,
+        "description": "Fabricated test data; never real client results.",
+        "title": "Synthetic",
+        "type": "boolean"
+      }
+    },
+    "required": [
+      "synthetic",
+      "not_a_lodgment",
+      "entity",
+      "form_type",
+      "income_statement",
+      "reconciliation"
+    ],
+    "title": "CtrFixture",
+    "type": "object"
+  }
+}

removedOutput schema / additionalProperties
```
Removed value: -true
```

addedOutput schema / anyOf

Added value: +[
+  {
+    "$ref": "#/$defs/CtrFixture"
+  },
+  {
+    "$ref": "#/$defs/BasFixture"
+  }
+]

changedOutput schema / title

Previous value: -"generate_synthetic_sbr_fixtureDictOutput"New value: +"SyntheticFixture"

Changed3 schema fields changedv0.1.7Sep 5, 2026

addedInput schema / properties / entity_name / description

Added value: +"Fabricated entity label for test output; defaults to \"Synthetix Pty Ltd\". Do not supply real client data."

addedInput schema / properties / form_type / description

Added value: +"Fixture type: \"CTR\" (company tax return) or \"BAS\" (activity statement), case-insensitive. No other forms are supported."

addedInput schema / properties / revenue_or_sales / description

Added value: +"Fabricated gross revenue (CTR) or total sales G1 (BAS); defaults to \"1000000.00\". Other figures use fixed demonstration assumptions. AUD decimal string, e.g. \"1000.00\"; finite, at most 2 decimal places, absolute value at most 1000000000000.00."

First observedv0.1.6Aug 26, 2026

TDQS

A3.9/5.0

Behavior4/5

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

Annotations already declare readOnly, non-destructive, idempotent, closed-world. The description adds substantive context beyond that: output marked synthetic=true and not_a_lodgment=true, no file writes/network/lodgements, not a real tax calculation, not statutory advice. It could state more about what the payload contains, but it clearly marks the safety and scope boundaries.

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-loads the purpose in one sentence and uses a short paragraph for constraints, then closing disclaimers. Reasonably efficient. The revenue example and disclaimer lines are slightly verbose but each earns its place for a safety-sensitive generator.

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?

Output schema exists, so return values need not be explained. For a synthetic-fixture generator with rich annotations and a fully documented schema, the description covers scope, safety and output markers. Missing only detail on exact payload contents, which the output schema presumably carries.

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 coverage is 100%, so the schema already documents all three parameters. The description repeats the revenue_or_sales constraint (decimal string, 2dp, magnitude cap) and the form_type semantics, which adds little over the schema; it doesn't expose details like accepted form codes beyond what the schema states. Baseline 3 is appropriate.

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

Purpose4/5

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

States a clear verb+resource: generate fabricated CTR/BAS payloads for testing an agent integration. The tool's role as a test-fixture generator is explicit. It doesn't differentiate from siblings, but siblings are all analysis/lookup tools, so the distinction is implicit — no sibling generates payloads.

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?

Explicitly scopes usage: 'for testing an agent integration' and 'Use only with synthetic inputs,' with a clear warning against real client data. It doesn't name an alternative, but no sibling overlaps, so the usage boundary is clear without an explicit exclusions list.

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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