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

Annotations already cover the safety profile (readOnly, openWorld, non-destructive), and the description adds genuinely non-structured context: the 2-credit cost and the fact that it also flags bot traffic and CPU architecture, which matters for interpretation. Minor gap: no note on behavior for malformed or empty UA strings, which is plausible input here.

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?

Two sentences, front-loaded with what it does and followed by the payoff and cost. Minor waste: the name/title are repeated verbatim before the sentence, which adds no information.

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?

An output schema exists, so return values need not be described; the description nonetheless previews the result categories, which is enough for a single-parameter parser. The only missing piece is disambiguation from the sibling generator 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?

Only one parameter, fully documented in the schema with an example, so the schema carries the semantics. The description does not add format guidance (e.g., full UA header vs. trimmed string), so this sits at the baseline for high schema coverage.

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?

States a specific verb and resource (parses user agent strings) and enumerates the extracted dimensions: browser, OS, hardware, device type, CPU architecture, bot traffic. It does not, however, differentiate itself from the sibling UserAgentGenerator, which an agent could plausibly confuse with it.

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 clause 'run user agent detection on every incoming HTTP request' implies the usage context, but there are no explicit when-to-use/when-not rules and no named alternatives despite close siblings like UserAgentGenerator, BotDetector, and VPNProxyDetector.

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