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

With no annotations, the description bears the burden of disclosing behavior. It specifies the output format (dict with time-related fields) and the optional parameter (IANA timezone). It does not mention any side effects or latency, but for a simple time retrieval tool, this is adequate.

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 a single sentence that immediately states the purpose ('Current moment as dict') and follows with examples of output fields and the optional parameter. Every part is essential, and the structure is front-loaded.

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 tool with one optional parameter and an output schema (likely detailed), the description covers the key aspects: what it returns, the optional timezone input. It lacks specification of default behavior when tz is null, but overall it is sufficiently complete for the tool's complexity.

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?

The only parameter 'tz' has a schema type of string or null. The description adds the key context that it expects an IANA timezone string, which is not present in the schema. Given zero schema description coverage, this compensation is valuable and clear.

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 that the tool returns the current moment as a dict with specific fields (iso, date, weekday, ...). It distinguishes itself from sibling tools like calc, calc_convert, and calendar, which are for calculations, conversions, and calendar functions respectively.

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 implies usage for obtaining current time information, but provides no explicit guidance on when to use this tool over alternatives. Sibling tools are sufficiently different, but the description lacks direct 'when-to-use' advice.

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