Fetch a sessionStorage item by key to read session data during automated browser tasks. Returns null when the key does not exist.
Get a sessionStorage item by key. Returns null if absent.
| Name | Required | Description | Default |
|---|---|---|---|
| key | Yes |
Changes observed during successful MCP inspections.
v1.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the behavioral disclosure burden. It usefully states that the tool returns null if the key is absent, but it does not mention the return type for present keys, page/origin context, or any other behavior.
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 a single sentence with no filler. The core operation is front-loaded and every word contributes to the meaning.
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 simple one-parameter getter, the description is close to adequate: it names the operation and the absent-key return behavior. However, with no output schema and no annotations, it omits the present-key return type and any context about which storage origin is accessed.
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 description coverage is 0%, so the description must compensate for parameter documentation. 'By key' essentially restates the schema property 'key' without adding format, examples, or clarification of what counts as a valid key.
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 operation: getting a sessionStorage item by key. It also clearly distinguishes the tool from siblings like browser_sessionstorage_set, browser_sessionstorage_delete, and browser_localstorage_get.
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?
There is no guidance on when to use this tool versus alternatives. It does not mention localstorage_get, sessionstorage_list, or any condition that would select this tool over a sibling.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.