Mithwire MCP

browser_tab_list

List open browser tabs and identify the active tab for a session, so AI agents can inspect or manage the current browsing context.

Instructions

List open tabs and the active 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": {
      "session_id": "<session_id>"
    },
    "name": "browser_tab_list"
  }
}

Input Schema

Name	Required	Description	Default
`session_id`	Yes

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.5.1Oct 18, 2026

TDQS

B3.1/5.0

Behavior3/5

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

No annotations are provided, so the description carries the full behavioral burden. "List" implicitly signals a read-only, non-destructive operation and the presence of the active tab among the results is disclosed, but there is no statement about ordering, pagination, or that this never mutates browser state. The implicit read-only semantics keep it at a minimum-viable 3 rather than lower.

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?

One short sentence, front-loaded with the verb and resource, no boilerplate or repetition. Every word earns its place.

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

Completeness3/5

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

An output schema exists, so return values need not be explained here, and the operation itself is simple. What is missing is any routing versus the closely related browser_tab_current, browser_tab_switch, and browser_tab_new siblings, plus any meaning for the undocumented session_id.

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

Parameters2/5

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

Schema description coverage is 0% and the single session_id parameter has no description in either the schema or the tool description. The description does not compensate at all, leaving the agent to guess whether session_id refers to a browser session key or something else; only the sibling-tool context makes it inferable.

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

Purpose4/5

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

The description gives a specific verb and resource ("List open tabs") plus the scope of what is returned ("and the active tab"), so the agent knows exactly what this tool produces. However it never distinguishes itself from the very similar sibling browser_tab_current, which also surfaces the active tab, so there is no explicit sibling differentiation.

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

Usage Guidelines2/5

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

There is no when-to-use, when-not-to-use, or alternative guidance. The agent must infer from the name alone that this is the enumeration counterpart to browser_tab_current / browser_tab_switch, and nothing tells it when listing all tabs is preferable to reading the current tab.

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

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