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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety behavior is covered. The description adds real domain substance — the full rule list it evaluates and the fact that it reports remaining drive/window time — but says nothing about result shape, error handling, or how ambiguities (missing prior days, time zone conversion) are treated.

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 purpose, then coverage, then the input-format instruction. The long parenthetical rule list is dense but earns its place by defining evaluation scope; only the trailing offset instruction slightly duplicates the schema.

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 seven-parameter regulatory calculator with no output schema, the description conveys enough: what it evaluates, which rule parts, and that it returns violations plus available remaining time. A brief note on result structure would close the remaining gap.

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 all seven parameters including cycle, carrier, shortHaul, adverse, and priorDailyOnDutyHours are already documented. The description's one added constraint — events in time order with ISO 8601 times including an offset — is a useful emphasis on the most common input failure mode but largely restates the schema's own wording.

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 — find every hours-of-service violation in a commercial driver's duty-status log — and scopes it to 49 CFR Part 395, with the secondary output (remaining time) named up front. This clearly separates it from maritime (mariner_rest_check) and driver-qualification (dq_file_check) siblings without needing to name them.

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 regulatory citation and the enumerated rule set (11/10-hour, 14/15-hour window, 30-minute break, 60/70-hour cycle, split sleeper, adverse conditions, short-haul, 16-hour) tell an agent exactly which inputs this tool applies to. It stops short of explicit when-not guidance or naming an alternative tool for adjacent checks.

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