browser_mock_date_and_time

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

No annotations are provided, so the description carries full burden. It discloses that the tool overrides Date, Date.now(), and performance.now() and that changes persist across page navigations. This is good but could further detail boundaries (e.g., effect on other tabs, limitations).

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, front-loaded with the core action and key details. Every sentence adds necessary information with no superfluous content.

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 no annotations and no output schema, the description covers the essential behavior: what it does, what it overrides, and persistence. It could mention return values or confirmation, but overall sufficiently complete for its 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 coverage is 100% and the description adds no additional meaning beyond what the schema provides for each parameter. Baseline 3 is appropriate as the schema already documents mode, deltaMs, and isoDate with clear descriptions.

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?

Description uses specific verbs ('mock, freeze, or shift') and clearly identifies the resource ('browser time') and its scope (overrides Date, Date.now(), performance.now(), persists across navigations). It distinguishes itself from sibling tools, none of which perform time mocking.

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 use for deterministic testing but provides no explicit guidance on when to use this tool versus alternatives, nor when it should not be used. Given no competing time-mocking siblings, the context is clear but formally lacking.

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