move_tab

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

Despite annotations already flagging mutation (readOnly=false) and non-destructiveness, the description goes far beyond by disclosing that the tab keeps its id/history/page state, works on chrome-untrusted:// tabs, and the exact error message for invalid destinations. This is valuable behavioral context not captured in annotations.

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 front-loaded with purpose and every sentence adds relevant detail. However, it is a single dense paragraph with somewhat anecdotal content (e.g., 'verified on a ChromeOS Terminal tab') that could be tightened without losing value. Still, it remains purposeful.

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 (9 params, no output schema), the description thoroughly covers constraints, error conditions, and a real-world use case. The only notable omission is the return value (what the caller gets after a successful move), but this is partially mitigated by the schema's parameter detail and the clear action-oriented nature of the 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 description coverage is 100%, so the baseline is 3. The description adds meaningful context for new_window ('tabs.move needs an existing window, this does not') and for window_type (the terminal-window look). All other params are already well-described in the schema, so this extra context pushes it above baseline.

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 first sentence immediately states the action: 'Move an existing tab into another window (chrome.tabs.move).' This is a specific verb + resource that distinguishes it from tab creation or tab_action siblings. It further clarifies the non-destructive nature and the new_window option, reinforcing purpose.

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 explicitly states when not to use it: 'moving into [an app or popup window] is refused'. It also provides an alternative within the tool: 'new_window' for extracting a tab, and suggests 'viewport_resize' for positioning. The ChromeOS Terminal example gives concrete usage context.

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