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

With no annotations, the description carries the burden. It discloses that the tool works offline and extracts the timestamp, which is useful. However, it does not mention behavior on invalid input, output format, or other potential edge cases. Still, the core behavior is stated.

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 with no filler. The action and target are front-loaded, and every word contributes meaning. This is concise and well-structured.

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 simple, has an output schema (covering return values), and the annotations are absent. The description tells the agent what it does and that it is offline. It does not explain edge cases or input validation, but for a straightforward decode operation, this is largely sufficient.

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 0% and the description does not explicitly state that the 'q' parameter is the ULID string. While the tool name and description imply it, the mapping is not explicit. For a single parameter, the description should at least say 'q expects a ULID string' to compensate for the missing schema description.

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 ('Decode'), a specific resource ('a ULID's embedded timestamp'), and the offline nature of the operation. This clearly distinguishes it from siblings like uuid or uuid_validate, and 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?

The description implies usage—when you have a ULID and need its embedded timestamp—but does not explicitly mention alternatives or when not to use it. The 'offline' qualifier provides some guidance, but no exclusions or sibling comparisons are given.

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