browser_get_prefReads a named Firefox preference in a privileged context and returns its type and value, enabling agents to inspect browser settings.
Read a preference by name (privileged context). Returns type and value.
| Name | Required | Description | Default |
|---|---|---|---|
| name | Yes | Preference name, e.g. browser.tabs.inTitlebar |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The readOnlyHint annotation already establishes the safety profile. The description adds useful context by noting the privileged context and that the result includes type and value, though it omits error or not-found 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?
It uses two short, front-loaded sentences with no filler. Both sentences carry operational information.
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 one-parameter read tool with no output schema, the description gives the essential context: privileged read by name and a basic return shape of type and value. It could say more about missing preferences or exact return structure, but it is largely 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?
Schema description coverage is 100% and the only parameter is already documented with an example. The description's 'by name' adds no syntax or format detail beyond the schema, so the baseline of 3 applies.
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 verb and resource: read a preference by name. It does not explicitly distinguish this getter from the sibling browser_search_prefs, but the by-name scope is clear enough for selection.
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 phrase 'by name' implies when to use this tool, but there is no explicit guidance about when to use it instead of browser_search_prefs or other preference tools. Usage is inferable rather than stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.