assign_split_to_lot

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

Annotations mark this as destructiveHint=true and idempotentHint=true, so the description must clarify the destructive effect, but it only says 'link' and 'for cost basis tracking.' It does not explain whether an existing split-lot assignment is overwritten or whether the operation has consequences beyond linking. This is a meaningful gap for a destructive operation.

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 well-structured with a one-sentence purpose, usage guidance, args list, and workflow. It is slightly longer than strictly necessary due to the example workflow, but the workflow concretely demonstrates how the tool fits into a multi-step process, so the length is justified.

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?

For a two-parameter tool with an output schema, the description provides the workflow, param sources, and when to use it. It is practically complete for correct invocation. The main missing context is the destructive behavior already penalized under behavioral transparency, but for agent invocation the description is sufficient.

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?

The schema already covers both parameter formats with 100% coverage, so the baseline is 3. The description adds useful context beyond the schema, especially for split_guid: 'GUID of the split (from transaction's investment account)' and the workflow showing how the split_guid and lot_guid are produced.

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?

States a specific verb and resource: 'Assign a transaction split to a lot.' It clearly identifies the object being operated on (a transaction split) and the target (a lot), and the rest of the description explains how this fits into the lot-assignment workflow, distinguishing it from lot creation and transaction creation tools.

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?

Explicitly says 'Use after creating a buy/sell transaction to link the investment account split to its lot for cost basis tracking' and reinforces this with a numbered workflow. It gives clear timing and context, though it does not explicitly list alternative tools or exclusionary conditions.

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