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

No annotations are provided, so the description carries the full burden of behavioral disclosure. The description only states the outcome and does not mention whether this is a read-only lookup, how the timezone is resolved, what output format is returned, or that the schema parameters are discarded. The schema's descriptions suggest unrelated shape-checking behavior, adding confusion rather than transparency.

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, direct sentence with no filler or repetition. It front-loads the core purpose and is appropriately concise for a simple lookup tool. The brevity itself is not the problem; the missing parameter alignment is.

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?

The definition is not complete enough for reliable invocation: there is no way to specify the named timezone, no output schema, no annotations, and no explanation of the unrelated input parameters. The mismatch between the description and the schema is severe enough that an agent could not confidently call this tool based on the provided definition.

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 description refers to a named IANA timezone, but the input schema has no timezone parameter and additionalProperties is false, meaning the necessary argument cannot be supplied. The schema parameters are described as Git refs, URLs, city names, feeds, hosts, JSON, and file paths, none of which relate to selecting a timezone. The description adds no usable parameter semantics and actually conflicts with the schema.

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 communicates that the tool returns the current time for a named IANA timezone, which distinguishes it from sibling tools like utc-time and iana-zones. It lacks an explicit verb such as 'gets' or 'returns', but the meaning is unambiguous. However, this stated purpose is not reflected in the input schema, which undermines the clarity when the agent tries to use the tool.

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 phrase 'named IANA timezone' implies when the tool should be used, and the sibling names suggest alternatives like utc-time and iana-zones. There is no explicit when-to-use or when-not-to-use guidance, nor any mention of alternatives. The agent is left to infer the usage context from the description and tool names alone.

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