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

The description goes beyond the annotations by disclosing that a file is written and that the path is returned. It does not mention overwrite behavior or idempotency, but the tier-based clamping is covered in the parameter schema, so the gap is minor.

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 sentences with zero filler: the purpose is front-loaded, the output format and row content are specified, and the return value is stated. Every phrase earns its place.

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 simple export tool, the description covers the essential decision inputs: output format, row content, intended use, and return value. The parameter schema handles defaults and tier clamping. A mention of overwrite behavior would make it fully complete.

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 schema already thoroughly documents all four parameters. The description adds useful output context like row fields and the returned path, but it does not add new meaning to the parameters themselves.

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 states a specific verb ('export'), a clear resource ('the timesheet'), and a concrete output ('CSV file'), along with the intended audience ('bookkeeper') and the row content. It is clearly distinguishable from sibling list/report 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?

The description explicitly opens with 'Call this tool to export the timesheet to a CSV file', which gives clear context for when to use it. It does not explicitly name alternatives or state when not to use it, so it stops short of a 5.

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