Lists every Firefox browser window for a given profile ID and can include tab information for each window.
List all browser windows
profile_id is required: obtain it from profiles_list. All object IDs are local to that profile; never reuse them in another profile.
| Name | Required | Description | Default |
|---|---|---|---|
| populate | No | Whether to include tab information for each window | |
| profile_id | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v1.6.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are supplied, so the description carries the full burden; "List" implies a read but is never stated. It does add a real behavioral constraint that IDs are profile-local and must not be reused across profiles, which is valuable context not found in the schema, but it says nothing about ordering, pagination, or what happens for an invalid profile_id.
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?
Two short sentences, the purpose stated first and the parameter prerequisite second. No filler and nothing buried.
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 an output schema present, return values need no explanation, and the description covers the one undocumented parameter. Only minor gaps remain around read-only semantics and result ordering for a simple two-parameter listing tool.
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 only 50% — profile_id has no schema description — and the description compensates by explaining where to get it and what its values mean (profile-scoped object IDs). The populate parameter is documented in the schema, so the description correctly does not duplicate it.
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?
States a specific verb and resource ("List all browser windows") with the scope word "all", which implicitly separates it from get_window and get_current_window. It stops short of naming those siblings explicitly, so an agent must infer the distinction from the names alone.
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?
Explains the prerequisite for the required parameter — obtain profile_id from profiles_list — which is a genuinely useful usage cue. It does not say when to prefer this over get_window, get_current_window, or tabs_list, so the choice among sibling read tools is left implied.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.