Mailshake MCP Server and API by Cotlet

Open the browser

cotlet_browser_open

Read-only

Starts the user's Cloud Browser (a real Chrome on Cotlet, where the user is signed in to their sites) and opens url. Call it first. The URL goes to the site's open tab, else to a new tab, so the user's own tabs stay. Answers the page after it: the elements and text in view, with the same numbers. In Mailshake it serves these actions: List campaigns, Add recipients to a campaign, List replies and leads, Reply to a lead, Add a follow-up to a campaign, Move leads to another campaign, Pause a campaign or recipient, Set lead status.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "cotlet_browser_open"
  }
}

Input Schema

Name	Required	Description	Default
`app`	No	Leave it out: the step runs in the user's web browser. Only when cotlet_app_guide names an app's own Cloud Browser, that app's slug, e.g. milanote.
`url`	No	A public http or https address, e.g. https://example.com.

Schema Changelog

Changes observed during successful MCP inspections.

First observedNov 9, 2026

TDQS

A4.1/5.0

Behavior5/5

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

Goes well beyond the annotations: it discloses that the session is an authenticated real Chrome, that the URL lands in the site's existing tab or a new tab so the user's own tabs are preserved, and that it returns the in-view elements and text with stable numbering. That return-format disclosure is valuable since no output schema exists.

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

Conciseness4/5

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

Front-loaded with the core action and the 'call it first' directive, then tab semantics, then return shape. The trailing Mailshake action enumeration is long but earns its place as routing context for which user tasks this tool unlocks.

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 two-parameter, no-output-schema tool, the description covers authentication context, ordering, tab effects, and return content, which is nearly everything an agent needs. The remaining gap is the unresolved overlap with cotlet_browser_navigate, which the agent must infer.

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 description coverage is 100%, so both url and app are already documented in the schema and baseline is 3. The description adds routing behavior for url (existing tab vs. new tab) but says nothing extra about the app parameter beyond deferring to cotlet_app_guide.

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?

States a concrete verb and resource: starts the user's Cloud Browser (a real Chrome on Cotlet where the user is signed in) and opens the given url. The scope and tab behavior are spelled out. It does not distinguish itself from cotlet_browser_navigate, which an agent could easily confuse with 'open url', so sibling differentiation is incomplete.

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?

'Call it first' is an explicit ordering directive that tells the agent when to invoke this tool relative to the rest of the flow. It also lists the Mailshake actions the resulting session serves, giving concrete usage context. It never states when not to use it or how it differs from the navigate sibling, so no exclusion guidance is present.

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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