Save browser authentication state

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

Beyond the annotations, the description adds meaningful behavioral details: data is stored privately, may contain credentials, is not returned to the model, and explicitly excludes sessionStorage, extensions, and open tabs. This is valuable context for a write operation and does not contradict the 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?

The description is two concise sentences with no filler. The core behavior is front-loaded, and the key exclusions and security caveat are packed efficiently into the second sentence.

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 single-parameter tool with a straightforward write-side purpose, the description covers what is saved, where, the security implication, and the consumer of the saved state. No critical invocation information is missing even without an output schema.

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 only parameter, session_id, is already fully documented in the schema as 'Session ID returned by tab_open.' The description adds no additional parameter-level detail, so the baseline of 3 applies given 100% 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?

The description states a specific action ('Save'), specific resources ('cookies, localStorage and IndexedDB'), and the destination ('private local artifact file'). It also defines the downstream purpose ('later tab_open storage_state import'), which clearly distinguishes this tool from snapshot/extraction siblings.

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 intended use case is clearly stated: preserve browser authentication state for a later tab_open import. It does not explicitly list alternatives or when-not-to-use conditions, but the stated purpose gives enough context for an agent to select this tool over reading/extraction tools.

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