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

Annotations already mark readOnly, idempotent, non-destructive. The description adds meaningful behavioral context: it returns a confidence level with a reason for anything below high, cites statutes, and explains why today's map is incorrect for past dates. This goes beyond annotations without contradicting them.

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?

While the description is long, it is highly structured with clear sections (DELEGATE, CITATION) and every sentence earns its place, providing critical warning and citation instruction. It front-loads the purpose and output without waste. Length is justified by complexity.

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?

No output schema exists, so the description fully explains the return values (IANA zone, offset, UTC instant, confidence, reason, statute citation). It also covers the when-to-use and citation requirement. For a 3-param tool with rich behavior, this is 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 documents date and time formats and place format. The description reiterates the purpose but does not add new meaning beyond the schema (e.g., 'omit time for midday' is already in schema). Baseline 3 is appropriate.

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 clear verb ('Resolves') and resource ('UTC offset in force at a place on a date'), then enumerates the outputs (IANA zone, signed offset, UTC instant, confidence, statute citation). It distinguishes from sibling astrology tools by being timezone/historical in nature. No ambiguity about what the tool does.

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?

Explicitly instructs the agent to delegate this rather than derive, with a concrete example (Tennessee/Knoxville) demonstrating why deriving fails. It also mandates citation requirements. This gives clear when-to-use and is far beyond implicit guidance.

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