browser_set_cookie

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

The tool is a write operation (consistent with readOnlyHint=false) and the description adds a key behavioral constraint: the browser must already be on the target domain. No additional details about overwrite behavior or errors, but adequate given annotations.

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?

Three concise sentences: purpose, use case, precondition. No fluff, 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?

With a full input schema, output schema, and annotations, the description covers the essential context (auth injection, domain requirement). Missing potential details like cookie overwrite behavior, but overall complete for this tool's simplicity.

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 has 100% description coverage for all 5 parameters, so the description doesn't add extra meaning beyond what the schema provides. Baseline score of 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 'Set a cookie on the current page' with a specific verb and resource, and distinguishes from sibling 'browser_get_cookies' by emphasizing the write operation.

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?

Provides practical guidance: useful for injecting auth tokens and requires the browser to be on the target domain. Lacks explicit when-not-to-use or alternative tools, but context is sufficient.

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