Charlotte

charlotte_tab_switch

Switch to a specific browser tab by providing its tab ID. Activates the target tab and returns its page representation.

Instructions

Switch to a different browser tab by its tab ID. Returns the page representation of the activated tab.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "tab_id": "<tab_id>"
    },
    "name": "charlotte_tab_switch"
  }
}

Input Schema

Name	Required	Description	Default
`tab_id`	Yes	ID of the tab to switch to

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv0.8.0Aug 10, 2026

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

removedInput schema / additionalProperties
```
Removed value: -false
```

First observedv0.6.3May 26, 2026

TDQS

A3.8/5.0

Behavior3/5

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

With no annotations provided, the description carries the burden of disclosure. It does reveal an important behavioral aspect: the tool returns the page representation of the activated tab. However, it does not mention what happens if the tab ID is invalid, whether focus changes, or any side effects beyond the switch. This is adequate but not rich.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two short sentences, no filler, and front-loads the action. Every word contributes to understanding the tool's purpose and return value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple tool with one parameter and no output schema, the description provides the essential information: what it does and what it returns. Some details like error cases are not covered, but the tool's simplicity makes the description sufficiently complete for an agent to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema provides 100% coverage for the single parameter tab_id with the description 'ID of the tab to switch to'. The tool description adds minimal extra meaning beyond restating 'by its tab ID', so it does not improve on the schema. Baseline 3 is appropriate given high schema coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Switch') and resource ('different browser tab') with the input identifier ('by its tab ID'). It clearly distinguishes itself from sibling tools like charlotte_tab_open and charlotte_tab_close by focusing on switching to an existing tab, and it also specifies the return value.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description makes the basic usage clear (switch to a tab by ID) but does not explicitly state when to prefer this over alternatives like charlotte_tabs or charlotte_tab_open. There are no exclusions or prerequisites mentioned, so guidance is implied rather than explicit.

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