open_firefox_tabs_into_group

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

With no annotations provided, the description carries the full transparency burden. It discloses important behaviors: tabs are opened in the background, the group is created only if missing, the operation is atomic, and on failure already opened tabs are closed. It does not mention all potential side effects, such as unpinning behavior or focus changes, but the core behavioral traits are well covered.

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, dense sentence with no filler. Every clause contributes essential information: background opening, grouping, atomicity, group creation condition, and rollback behavior. It is front-loaded with the main action and structured logically, making it both concise and effective.

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?

Given the tool's complexity, the lack of annotations, and the absence of an output schema, the description covers the key behavioral guarantees well: atomic batch opening, group creation/reuse, and rollback on failure. It does not explain what happens when groupTitle already exists beyond 'creating the group only if missing,' nor does it define failure conditions precisely, but it is sufficiently complete for most selection and invocation scenarios.

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 high (80%), so the baseline is 3; however, the tool description adds meaning beyond the schema by clarifying that URLs must be 'explicit http(s) URLs,' that the group is 'exactly named' and reused/created, and that the operation is atomic with rollback. The 'urls' parameter itself has no schema description, but the description compensates by defining what kind of URLs are accepted. This additional context raises the score to 4.

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 clearly states the action: 'Open a batch of explicit http(s) URLs in the background and put every new tab into one exactly named group in one atomic operation.' This distinctively differentiates from siblings like open_firefox_tab (single tab) and move_firefox_tabs_to_group (existing tabs), and it specifies the resource (URLs) and grouping behavior precisely.

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 when to use this tool: when you need to open multiple URLs at once into a single, specifically named tab group. It conveys this context clearly through 'batch,' 'exactly named group,' and 'atomic operation,' though it does not explicitly name alternatives or state when not to use it. This is clear context without formal exclusions, so a 4 is appropriate.

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