user_agent_parse

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

With no annotations provided, the description fully discloses behavioral traits: it runs synchronously, uses the ua-parser-js library, makes no external calls, and returns specific fields with empty strings for unknowns. This is comprehensive and leaves no ambiguity.

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 brief (four sentences) but packs all necessary information front-loaded. No redundant words; every sentence adds value.

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?

Despite having no output schema, the description enumerates the return fields (browser.name, etc.) and explains behavior for unknown values. It covers input, processing, output, and constraints, making it fully self-contained for a simple parsing tool.

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 already provides a description for the 'ua' parameter with an example. The tool-level description adds context on the output structure but does not significantly enhance understanding of the parameter beyond what the schema provides. Schema coverage is 100%, so baseline 3 is appropriate.

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 the tool's function: parsing a User-Agent header into structured components (browser, OS, device, engine). It uses a specific verb ('Parse') and resource, and distinguishes itself from sibling tools which are either network or encoding utilities.

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 a clear use case (analyzing server logs or request headers) and explicitly states that it performs no network lookups, which sets user expectations. However, it does not explicitly mention when not to use it or provide alternative tools, though no clear alternative exists among siblings.

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