create_tab

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

The description discloses that the new tab becomes 'the implicit target of later commands in this session' and that each call creates another tab, behaviors not captured by the annotations. This provides critical context about statefulness and side effects beyond the structured hints.

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 sentences, front-loaded with the primary action and followed by a practical usage tip. Every sentence contributes value with no redundancy.

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?

The description is fully self-contained for a state-changing tool: it explains the action, the session-wide implication, and the fallback to navigate(). It does not explicitly state the return value, but the mention of 'reuse a tab_id' implies a tab identifier is returned, which is sufficient given the tool's simplicity and the comprehensive schema.

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 minimal parameter-specific meaning beyond the schema, merely mentioning the optional URL, which is already documented. It does not introduce new information about parameters.

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 uses a specific verb ('Open') and resource ('new tab'), clearly distinguishing this from navigation tools. It explicitly contrasts with navigate(), stating 'reuse a tab_id or navigate() to move an existing one instead of piling up tabs.'

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 provides explicit usage guidance: it tells the agent that each call creates a new tab and recommends reusing a tab_id or using navigate() to move an existing tab, preventing tab accumulation. This addresses when to use the tool versus alternatives.

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