Close duplicate tabs

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

The only annotation is readOnlyHint=false, so the description must carry the mutation profile — and it does explain what 'duplicate' means (same page loaded) and guarantees one tab of each set survives, plus that a count is reported. It stops short of saying whether the closed duplicates land in the recently-closed list / are recoverable via browser_reopen_closed_tab, and whether the sweep spans all windows.

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?

Three short sentences: definition first, familiar analogy second, return value last. No restatement of the title, no filler, and the scoping rule ('keeping one of each') is front-loaded where it matters most.

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 zero params, no output schema and only a readOnlyHint annotation, the description covers the essentials including the return value ('reports how many were closed'), which is valuable given the missing output schema. Minor gaps: scope across windows/tab groups and recoverability of closed duplicates.

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 tool takes zero parameters and the schema is an empty object, so there is nothing for the description to disambiguate — baseline 4 applies. It correctly adds no pseudo-parameter speculation and instead spends its words on behavior.

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 (close) and precisely scoped resource (tabs that load the same page as another tab, keeping one of each), which cleanly separates it from browser_close_tab, browser_close_other_tabs, browser_close_tabs_to_right and browser_close_tabs_by_url. The parenthetical API reference (gBrowser.removeDuplicateTabs) pins down exact semantics.

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 the use case (deduplicating tabs) and anchors it to the tab context-menu cleanup, so an agent can infer when to reach for it. However, it never names the adjacent alternatives (browser_close_tabs_by_url, browser_close_other_tabs) or states when *not* to use it, leaving the selection decision to inference.

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