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

The description discloses the key side effects beyond annotations: it saves a transaction and, notably, auto-creates any #tag that does not exist yet. It also states that preview_entry can be used to see the parse without saving, giving an accurate picture of mutating behavior.

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?

Front-loaded with the core function in the first sentence, followed by compact examples and one routing tip. The example list is longer than strictly necessary but earns its place for a natural-language parser.

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 single-parameter command with an output schema, the description supplies usage patterns, side effects, and a safe preview alternative. Nothing essential for an agent to call it correctly is missing.

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 describes text as 'Phrase describing the transaction' (100% coverage). The description adds real value with concrete examples spanning amount, date, currency, transfer, and tag syntax, plus the tag-creation rule; it stops short of a formal grammar.

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 opens with a specific verb-resource pair: 'Parses a natural-language phrase and saves it as a transaction.' It also distinguishes itself from the sibling preview_entry by explicitly offering it for preview, and the title 'from a phrase' separates it from the structured add_transaction.

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 examples demonstrate the intended input style, and the closing sentence explicitly routes to preview_entry when the agent wants to avoid saving. It does not explicitly address the alternative structured add_transaction, so it is clear but not exhaustive.

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