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

Annotations already establish this is a non-read-only, non-destructive, non-idempotent mutation, and the description usefully reinforces the confirmation gate. It says nothing about whether the created transaction is returned, how invalid account_id or duplicate submissions behave, or how idempotencyKey interacts with idempotentHint=false.

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?

Two short sentences, front-loaded with the action and followed by the gating requirement — nothing is padded. It is efficient, though so terse that it borders on under-specified rather than genuinely concise.

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?

A 9-parameter mutation tool with one-third schema coverage, no output schema, and many adjacent transaction-creation siblings demands far more than two sentences. An agent lacks enough to choose this tool confidently or populate most parameters correctly.

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 only 33% across 9 params, so the description needs to carry weight and does not. It only restates the confirmation flag, whose behavior ('Must be true to execute the mutation') is already spelled out in the schema itself, leaving amount, account_id, category_id, type, and notes unexplained.

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 ('Add a new transaction'), so the basic action is unambiguous. However, it never distinguishes itself from close siblings like bulk_add_transactions or add_transaction_from_photo, which an agent could plausibly confuse it with.

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?

'Requires confirmation: true to execute' gives one concrete precondition for invocation. But there is no guidance on when to pick this over bulk_add_transactions, import_from_text, or add_transaction_from_photo, and no exclusions or follow-up steps.

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