Powerline Inbox Preview MCP
This MCP server allows AI agents to render HTML emails or .eml files in real, logged-in web clients for Gmail, Outlook, and Yahoo Mail to generate pixel-accurate screenshots. It also provides tools for email deliverability checks, including domain health, SPF, DKIM, DMARC, and blacklist verification, enabling agents to validate email rendering and authentication records.
Endpoint and access
No sign-in to connect and list tools. Individual tools may still need a vendor account, credentials, or permissions; check the documented prerequisites.
https://api.powerline.ai/v1/mcpWhat its tools do
4 tools, grouped by the hints the server advertises. Hints are self-declared, not verified behavior.
Not annotated (4)
Checks and signals
Each line is separate evidence, not a trust score.
- Passed Endpoint answered the live check ·
- Passed Official MCP Registry namespace is tied to powerline.ai ·
- Passed Endpoint is on the registry namespace domain ·
- Availability 1 of 1 checks passed in 30 days
What you can do with it
- Render HTML emails in real Gmail, Outlook, and Yahoo sessions
- Generate pixel-accurate screenshots of email rendering
- Check email domain health and deliverability scores
- Validate SPF, DKIM, and DMARC records
Source and maintenance
Protocol and capabilities
- Server
- inbox-preview 0.1.0
- MCP protocol negotiated in check
- 2025-11-25
- Tools
- 4 advertised
- Resources
- Not advertised
- Resource templates
- Not advertised
- Prompts
- Not advertised
{
"tools": {
"listChanged": true
}
}Tools
4 advertised
list_clients
List the email clients this deployment can render right now, with their rendering tier, engine, and capabilities
{
"type": "object",
"$schema": "http://json-schema.org/draft-07/schema#",
"properties": {}
}submit_preview
Submit an email for rendering across email clients — full HTML, or a complete raw .eml (base64). Provide exactly one of html/eml. Returns a job ID to poll for results.
{
"type": "object",
"$schema": "http://json-schema.org/draft-07/schema#",
"properties": {
"eml": {
"type": "string",
"description": "A complete raw RFC 822 message (.eml), base64-encoded — inserted verbatim (real headers, multipart, attachments). Max 10MB decoded. Provide exactly one of html or eml."
},
"html": {
"type": "string",
"description": "The full email HTML to preview. Provide exactly one of html or eml."
},
"renders": {
"type": "array",
"items": {
"type": "object",
"required": [
"client"
],
"properties": {
"client": {
"enum": [
"gmail",
"outlook",
"yahoo"
],
"type": "string",
"description": "Client ID"
},
"color_scheme": {
"enum": [
"light",
"dark"
],
"type": "string",
"description": "Render in the client's light or dark mode (default light). Dark must be supported by the client — check color_schemes in list_clients."
},
"viewport_width": {
"type": "number",
"description": "Viewport width in pixels (200-2560). Defaults to the client default (1280)."
},
"images_disabled": {
"type": "boolean",
"description": "Render with remote images blocked (default false)"
}
}
},
"description": "Exactly the renders you want, one entry each (e.g. outlook light + outlook dark are two entries). Omit for the server default: every live client at its default width, light."
},
"subject": {
"type": "string",
"description": "Email subject line"
},
"include_previews": {
"type": "boolean",
"description": "Also capture the inbox-list row (how the message looks unread in the list) and the subject heading, returned as inbox_preview / subject_preview on each render. Default false: they cost more than the body render itself, so ask only when you need them."
},
"include_full_page": {
"type": "boolean",
"description": "Also screenshot the whole client window around the opened email (the mailbox UI as well as the message), returned as full_page on each render next to the usual email-only screenshot. Default false. Best-effort: the render mailbox identity and any other mail are masked, and the capture is omitted when that cannot be verified."
}
}
}get_job
Get the status and screenshots for a preview job. Poll until status is "completed".
{
"type": "object",
"$schema": "http://json-schema.org/draft-07/schema#",
"required": [
"job_id"
],
"properties": {
"job_id": {
"type": "string",
"description": "The job ID returned by submit_preview"
}
}
}get_screenshot
Fetch a rendered screenshot. Returns the image URL for the given job, client, width, and environment (color scheme / images).
{
"type": "object",
"$schema": "http://json-schema.org/draft-07/schema#",
"required": [
"job_id",
"client",
"viewport_width"
],
"properties": {
"client": {
"enum": [
"gmail",
"outlook",
"yahoo"
],
"type": "string",
"description": "Client ID"
},
"job_id": {
"type": "string",
"description": "The job ID"
},
"color_scheme": {
"enum": [
"light",
"dark"
],
"type": "string",
"default": "light",
"description": "The render's color scheme"
},
"viewport_width": {
"type": "number",
"description": "Viewport width of the render, matching the job (1280 when the job used client defaults)"
},
"images_disabled": {
"type": "boolean",
"default": false,
"description": "Whether the render had images blocked"
}
}
}Prompts
Not advertised
Resources
Not advertised
30-day availability
Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.
- Successful checks
- 1 of 1 (100%)
- Average latency
- 273 ms
- 95th percentile latency
- 273 ms
Maintenance history
Public check and source-refresh events. Editorial and ownership records remain private.
- · probe · passed · 273 ms · metadata changed · 4 tool(s)
Connect from your client
Each snippet registers the same endpoint; pick the client you use.
Claude Code
claude mcp add --transport http powerline-inbox-preview-mcp https://api.powerline.ai/v1/mcpCodex
codex mcp add powerline-inbox-preview-mcp --url https://api.powerline.ai/v1/mcpCursor
{
"mcpServers": {
"powerline-inbox-preview-mcp": {
"url": "https://api.powerline.ai/v1/mcp"
}
}
}Cline
{
"mcpServers": {
"powerline-inbox-preview-mcp": {
"type": "streamableHttp",
"url": "https://api.powerline.ai/v1/mcp",
"disabled": false
}
}
}VS Code
{
"servers": {
"powerline-inbox-preview-mcp": {
"type": "http",
"url": "https://api.powerline.ai/v1/mcp"
}
}
}Gemini CLI
gemini mcp add --transport http powerline-inbox-preview-mcp https://api.powerline.ai/v1/mcpClaude Desktop
https://api.powerline.ai/v1/mcpWindsurf
{
"mcpServers": {
"powerline-inbox-preview-mcp": {
"serverUrl": "https://api.powerline.ai/v1/mcp"
}
}
}Let your agent find its tools
Find servers like Powerline Inbox Preview MCP from your agent. Add Koskamo once to search the index for endpoints, access requirements, and client setup. Public discovery needs no key.
Other developer tools servers
Do you run Powerline Inbox Preview MCP?
Prove ownership with a DNS record, a well-known file, or your Official MCP Registry entry, and your edits publish immediately. Proofs are re-checked weekly; admins can still hide or remove a listing.