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

With no annotations, the description carries the full burden. It discloses the primary write action and the auto-create side effect, but it does not mention whether it appends to existing sheets, handles duplicates, or requires specific permissions. These are notable omissions 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 two short sentences, front-loaded with the core action. Every phrase earns its place, making it efficient and easy to parse.

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 6 parameters, only 2 required, no output schema, and no annotations, this description is insufficiently complete. It does not explain return values, error behavior, or parameter meanings, leaving the agent to guess at critical details for correct invocation.

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?

Only 1 of 6 parameters (category) has a schema description, and the tool description does not elaborate on any parameter. Required fields 'amount' and 'description' lack format or interpretation details, especially since amount is typed as string. The description fails to compensate for the low 17% schema coverage.

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 a specific verb ('Log') and resource ('expense tracker in Google Drive'), making its purpose unambiguous. It distinguishes itself from sibling tools like get_expenses (read operation) and append_to_sheet (generic write) by targeting the expense logging domain.

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 phrase 'to your expense tracker' implies the intended use case, and 'Auto-creates spreadsheet if needed' gives context that no prior setup is required. However, it does not explicitly contrast with alternative tools (e.g., append_to_sheet) or state when not to use it, leaving usage guidance implied rather than explicit.

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