About Omniseal
Omniseal is an MCP service for concealing, retrieving, verifying, and removing hidden files with PureCipher Omniseal. It targets workflows that handle hidden files through MCP clients, using a remote Streamable HTTP endpoint; file contents and operation seeds are processed by PureCipher's hosted service.
Key features
- 01Conceal files inside supported covers
- 02Retrieve hidden files with a private seed
- 03Verify seal integrity without a seed
- 04Create a clean cover using a private seed
- 05Preserve original input files
Use cases
- 01Hide a secret file inside a supported cover
- 02Retrieve and check a concealed file
- 03Remove a hidden file and create a clean cover
MCP support
The service exposes tools for concealing, retrieving, verifying, and removing files to MCP clients over a remote Streamable HTTP endpoint.
Configuration
Remote servers need no local install. Pick your client, then copy the config or install in one click.
https://api.purecipher.com/mcp?platform=claudeclaude mcp add --transport http purecipher-omniseal https://api.purecipher.com/mcp?platform=claude{"mcpServers":{"purecipher-omniseal":{"type":"http","url":"https://api.purecipher.com/mcp?platform=claude"}}}Open in Cursor{"servers":{"purecipher-omniseal":{"type":"http","url":"https://api.purecipher.com/mcp?platform=claude"}}}Open in VS Code{"mcpServers":{"purecipher-omniseal":{"type":"http","url":"https://api.purecipher.com/mcp?platform=claude"}}}{"mcpServers":{"purecipher-omniseal":{"serverUrl":"https://api.purecipher.com/mcp?platform=claude"}}}Run commands in a terminal; paste JSON into the client’s MCP config and restart. Servers that need sign-in will prompt on first connect.
Tools
4| Parameter | Type | Required | Description |
|---|---|---|---|
| cover_file | object | Yes | An explicitly supplied file. Provide exactly one HTTPS download URL or exact base64 bytes. Claude attachment IDs and local paths are not downloadable URLs. |
| cover_file.file_name | string | Yes | |
| cover_file.mime_type | string | No | |
| cover_file.download_url | string | No | |
| cover_file.content_base64 | string | No | |
| secret_file | object | Yes | An explicitly supplied file. Provide exactly one HTTPS download URL or exact base64 bytes. Claude attachment IDs and local paths are not downloadable URLs. |
| secret_file.file_name | string | Yes | |
| secret_file.mime_type | string | No | |
| secret_file.download_url | string | No | |
| secret_file.content_base64 | string | No | |
| private_seed | string | Yes | User-supplied Omniseal private seed. Never use an account password or API credential. |
Details
From the project READMEOmniseal MCP service
Seal, retrieve, verify, and remove hidden files using PureCipher Omniseal.
Connect
Remote Streamable HTTP endpoint:
https://api.purecipher.com/mcp?platform=claude
No account, OAuth, or API key is required for the current public endpoint. For Cline setup, see llms-install.md. Other MCP clients can use the same endpoint with their HTTP transport configuration.
Tools
seal_files: conceal a secret file inside a supported cover.retrieve_secret_file: recover the hidden file using its private seed.verify_sealed_file: check seal integrity, without a seed.remove_hidden_file: create a new clean cover using the private seed.
Original input files are preserved. This repository contains the MCP connection documentation configuration and instructions. The hosted service executes the Omniseal SDK.
Inputs and output limits
Each file argument contains file_name and exactly one of download_url
(a service-reachable HTTPS URL) or content_base64 (exact file bytes).
Local paths and chat attachments are not automatically uploaded.
Selected file contents and the operation seed are processed by PureCipher's hosted service. Use an Omniseal seed, never an account password or API credential. Inputs are limited to 6 MB per file and 10 MB combined for sealing. Responses are limited to 140,000 serialized characters, typically about 100 KB of output bytes. Outputs are binary MCP resources, not hosted download links. Client-side binary rendering and saving have not yet been verified end to end.
The service URL is https://api.purecipher.com/mcp?platform=claude. The query
selects the existing compatible file schema; it does not send files to Anthropic.
The service is publicly reachable and requires no authentication.
Validation
Validated with Gemini CLI 0.63.0: installation and MCP connection succeeded. All four live MCP operations passed synthetic PNG/PDF tests, including exact recovery of the secret bytes. Model-mediated execution remains unverified.
Support
Copyright 2026 PureCipher. All rights reserved.
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