set_user_agent

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

With no annotations, the description fully discloses the behavioral traits: it applies to the current tab, persists until clear_user_agent or tab close, and requires platform to match the UA. It does not mention side effects or permissions, but for a header-setting tool this is sufficient.

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 two sentences with no wasted words. The first sentence lists what is overridden, the second explains scope and gives a practical tip. It is front-loaded and highly concise.

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?

For a tool with 3 parameters and an output schema, the description covers the key aspects: what it does, its scope, and parameter relationships. It does not explain the output, but the rule states output schema can carry that burden. Overall, it is fairly complete.

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 0% coverage (no parameter descriptions), so the description adds meaning by explaining each parameter: user_agent, accept_language, and platform. It provides an example for platform ('Win32') and notes it should match the UA. However, it does not detail format constraints for user_agent or accept_language, leaving some ambiguity.

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 overrides User-Agent, Accept-Language, and navigator.platform for subsequent requests on the current tab. It uses a specific verb ('Override') and resource, and distinguishes from siblings like clear_user_agent.

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 explains when the override applies (every subsequent request until cleared) and mentions the alternative clear_user_agent to revert. It implicitly tells the agent when to use this tool by describing its persistent effect, though it lacks explicit when-not-to-use or alternative tools beyond the clearance one.

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