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

With no annotations, the description carries the full burden of behavioral disclosure. It only says 'Current time in a named IANA timezone,' without explaining network access, error behavior for invalid zones, return format, or side effects. The sparse text leaves critical behavior undocumented for a tool that likely requires external calls.

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 concise (one sentence) and front-loaded with the main purpose, which is good. However, given the tool has 9 parameters and multiple seemingly unrelated fields, the brevity is excessive and fails to provide a structured overview. It is appropriately sized for a trivial tool but not for one with this 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?

The tool has 9 optional parameters, no output schema, and no annotations, yet the description is a single sentence that ignores most of them. The presence of parameters like 'ref', 'url', 'city', 'feed', 'host', 'json', 'path', and 'query' is unexplained and seems incongruent with a timezone lookup. An agent cannot determine what these are for or how they relate to the stated purpose, making the description severely incomplete.

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%, so every parameter is documented in the input schema. The description adds no additional parameter context; it doesn't even mention the 'zone' parameter. Per the baseline rule for high schema coverage, a score of 3 is appropriate because the schema carries the semantic load.

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 specific verb and resource: 'Current time in a named IANA timezone.' It is clear what the tool does, but it does not differentiate from sibling tools like utc-time or iana-zones. The purpose is understandable but not unique among the sibling set.

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 no guidance on when to use this tool versus alternatives. It does not mention utc-time for UTC time or iana-zones for zone lists, nor does it state any conditions for selection. An agent would have no basis to choose this over its siblings.

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