split_transaction

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

With no annotations, the description carries the full burden of behavioral disclosure. It discloses a critical constraint ('split amounts MUST add up to the parent transaction amount') and that unsplit 'restores it to normal', which gives some insight. But it omits details such as what happens to existing split data upon unsplit, potential errors (e.g., when amounts don't sum), or permissions needed, leaving significant behavioral gaps for a mutation tool.

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?

The description is concise and well-structured, with a front-loaded sentence defining the verb and resource, followed by action-specific instructions. Every sentence earns its place, and it avoids unnecessary fluff. The two-paragraph structure makes it easy to scan for the relevant action.

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?

Given the tool's moderate complexity (3 parameters with a nested split object) and detailed schema, the description covers the main usage comprehensively: both actions, required fields, and the sum constraint. However, since there is no output schema, the description could have explained what the tool returns or how errors surface, which is a gap. Still, it is fairly complete for a specialized mutation tool.

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 100%, so the baseline is 3. The description reiterates parameter meanings but adds minimal new information beyond the schema, such as structuring usage by action. The sum constraint is already in the schema's split item description, so the description does not significantly enhance understanding of parameters beyond what the schema already provides.

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?

The description clearly states 'Split or unsplit a Lunch Money transaction' with specific verbs and resource, immediately identifying the tool's core function. It distinguishes itself from sibling tools by focusing exclusively on split/unsplit operations, unlike manage_transaction or group_transactions which handle general edits or grouping.

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?

The description provides explicit context for when to use each action: action='split' requires id and splits array, action='unsplit' only requires the parent id. It clearly explains the required input structure for both modes, making the usage context unambiguous. However, it does not mention alternatives or explicitly state when not to use this tool, so it stops short of a perfect score.

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