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

Annotations already declare readOnlyHint=true, and the description adds a useful behavioral detail: the tool will not guess a date when formationDate is missing for affected states. This goes beyond the annotation by explaining the tool's fallback 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?

Two sentences, front-loaded with the main purpose and a conditional nuance, with zero waste. Every word 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?

Despite lacking an output schema, the description specifies exactly what the tool computes (due date, amount, penalty) and the behavior when formationDate is omitted. This is complete for a simple read-only tool with strong schema coverage.

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 coverage is 100%, with both state and formationDate already described. The description restates that formationDate is required for certain states, which is already in the schema, so it adds little new parameter-level meaning beyond the structured fields.

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 'Work out when a state's annual report or franchise tax is next due, the amount owed, and the late penalty,' clearly stating the specific verb, resource, and scope. It distinguishes itself from siblings like get_llc_fees or check_llc_name by focusing on deadlines and penalties.

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 provides clear context: formationDate is required for anniversary- or quarter-based states, and the tool explicitly says so rather than guessing. It doesn't explicitly name alternatives, but the purpose is distinct enough that the usage context is evident.

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