monarch-mcp2

Transactions Update Transaction Splits

transactions_update_transaction_splits

Modify the splits of a transaction in Monarch Money by providing updated amounts, categories, tags, or notes for each split.

Instructions

Update transaction splits. This may create or update Monarch data.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "transaction_id": "<transaction_id>",
      "splits": "<splits>"
    },
    "name": "transactions_update_transaction_splits"
  }
}

Input Schema

Name	Required	Description	Default
`fields`	No	Optional dotted output field paths to return, such as ['id', 'merchant.name', 'category.name'].
`splits`	Yes
`output_mode`	No	Output shape to return. Use summary for compact CLI-style defaults, full for complete structured data without raw, and raw for complete structured data including raw payloads.	summary
`session_path`	No
`transaction_id`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jul 5, 2026

TDQS

C2.9/5.0

Behavior3/5

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

Annotations already indicate readOnlyHint=false (write) and destructiveHint=false. The description adds 'may create or update Monarch data', which is consistent but adds minimal extra behavioral context. It does not detail what happens to existing splits or side effects beyond 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?

Two sentences with clear purpose and a behavioral note. No redundancy, but could include more relevant details without becoming verbose.

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

Completeness2/5

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

For a tool with 5 parameters including a complex nested 'splits' input and no output schema, the description lacks essential context about how splits are structured, how they relate to the parent transaction, and any constraints (e.g., sum of splits must equal transaction amount).

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

Parameters2/5

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

Schema description coverage is only 40%, and the description does not explain any parameters (e.g., transaction_id, splits). The nested 'splits' object has many fields but no description, failing to compensate for low coverage.

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?

The description clearly states 'Update transaction splits' as a verb+resource. It distinguishes the tool as an update operation, but does not differentiate from related tools like 'unsplit_transaction' or 'create_transaction'.

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

Usage Guidelines2/5

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

No guidance on when to use this tool versus alternatives (e.g., unsplit_transaction, create_transaction). The description does not mention prerequisites or scenarios where this tool is appropriate.

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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