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

There are no annotations, so the description carries the full burden of behavioral disclosure. It implies a read-only operation (getting current time) but does not explicitly state side effects, rate limits, or whether the call is stateless. For a simple time lookup, the minimal description is adequate but not rich; it adds no context beyond the obvious action. Given the simplicity, a score of 3 is appropriate.

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, concise sentence that is front-loaded with the core action and resource. It contains no filler or redundant wording, making it an example of efficient specification.

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 is named 'timezone' yet the schema includes 9 unrelated parameters (ref, url, city, feed, host, json, path, query) that appear to have no connection to timezone functionality. The description does not explain why these parameters exist or whether they are ignored, making the tool's behavior confusing. For a tool with such a broad schema, the description is incomplete and fails to clarify the intended usage context.

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 schema has 100% parameter description coverage, meaning every parameter (ref, url, city, feed, host, json, path, zone, query) has a textual description. The tool description adds no additional parameter semantics beyond mentioning 'IANA timezone' which aligns with the zone parameter. Since the schema already provides full meaning, the description adds little value, so the baseline of 3 applies.

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 'Current time in a named IANA timezone' clearly states the action (getting current time), the resource (a timezone), and the specific standard (IANA). It distinguishes itself from siblings like utc-time (which returns UTC) and iana-zones (which lists zones). The purpose is unambiguous.

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?

No guidance is given about when to use this tool versus alternatives such as utc-time or iana-zones. The description does not mention any exclusions, prerequisites, or conditions that would direct an agent to select this tool over others. It simply states what it does without situational context.

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