Charlotte

charlotte_tab_close

Close a browser tab by its ID. If the closed tab was active, automatically switch to the first remaining tab.

Instructions

Close a browser tab by its ID. If the closed tab was active, switches to the first remaining 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_close"
  }
}

Input Schema

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

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

A4.2/5.0

Behavior4/5

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

No annotations are provided, so the description carries the behavioral disclosure burden. It adds useful context beyond the action itself: if the closed tab was active, it switches to the first remaining tab. This discloses a side effect that an agent would not otherwise know.

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 sentences with no redundant words. It front-loads the core action and then adds one key behavioral detail, making it easy to parse quickly.

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 single-parameter tool with no output schema, the description is largely complete. It could benefit from mentioning where the tab_id comes from (e.g., from charlotte_tabs), but the sibling context and clear action make this a minor gap.

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?

Schema coverage is 100% because the only parameter is tab_id with a clear description. The description's 'by its ID' merely restates the schema, adding no additional semantic detail about the parameter's format or source.

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 states the specific verb 'Close' and resource 'browser tab', clearly distinguishing this tool from siblings like charlotte_tab_open and charlotte_tab_switch. The addition 'by its ID' specifies the exact input needed.

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

Usage Guidelines4/5

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

The description makes the usage context obvious: use this when you want to close a browser tab. It doesn't explicitly mention alternatives, but sibling tool names (tab_open, tab_switch) provide enough differentiation to infer when this tool is appropriate.

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