What Is DeepSeek Harness? An Open-Source Agent Runtime Explained

What Is DeepSeek Harness? An Open-Source Agent Runtime Explained

On AI

DeepSeek Harness is built to accomplish specific tasks—not just answer questions. Think of it as the glue between an AI model and the outside world. This open-source agent runtime connects your language model to file storage, command terminals, tools, and session history. When asked to fix a bug, it can automatically inspect files, modify code, run tests, and respond when commands fail. A single model call alone can't do any of that.

Here's what makes this interesting: Harness treats the runtime architecture itself as a first-class concern. DeepSeek Harness packages model adapters, tools, sessions, sandboxed environments, and agent loops as pluggable components orchestrated by Cordis. The model isn't the whole agent—it's just one piece of it.

Fair warning: this isn't production-ready yet. Harness is currently in developer preview, which means APIs can change between releases and security validation is incomplete. We'll cover these limitations alongside the system architecture and how it compares to Claude Code, Codex, and OpenCode.

Article Contents

• What Is DeepSeek Harness?
  • DeepSeek Harness Isn't an AI Model
  • DeepSeek Harness Isn't Just a Coding Assistant
• How Cordis Organizes DeepSeek Harness Plugins
  • Everything Is a Plugin
  • Spatial Composability Manages Plugin Dependencies
  • Temporal Composability Reverses Plugin Effects
• DeepSeek Harness Architecture: How the Runtime Works
  • Cordis Services Let Plugins Find Each Other
  • Agent Presets and Runtime Profiles Control Different Layers
  • Agent Loop Orchestrates Turns, Steps, and Tool Calls
  • Sessions Use Append-Only Event Logs
• How DeepSeek Harness Controls Tools and Sandboxing
  • Tool Execution Process
  • Sandboxing vs. Approval Mechanisms
• Conclusion

What Is DeepSeek Harness?

DeepSeek Harness (abbreviated dsh) is an open-source agent harness from DeepSeek AI, released under the MIT license. It sits between a language model and the external world, providing tools, sessions, sandboxed execution environments, and agent loops to keep task execution moving forward.

DeepSeek's core definition is simple: "Agent = Model + Harness". The model handles reasoning and content generation. The harness contains everything that lets that reasoning actually impact real file systems and continue working without requiring users to re-explain the task at each step.

The whole system runs on Cordis—a plugin framework that predates DeepSeek Harness. Cordis lets you swap components independently. This architecture leads to two common misconceptions.

DeepSeek Harness Isn't an AI Model

The model and runtime are separate layers. This separation means you can switch service providers without touching your tools or session configuration. The same runtime can use DeepSeek, Anthropic, OpenAI, or any OpenAI-compatible endpoint. They're interchangeable.

DeepSeek Harness Isn't Just a Coding Assistant

The Standard mode makes it look like a code-focused tool, but that's just one configuration option. Minimal and Creator modes change what the agent can access. Building a custom configuration requires actual programming—developers get direct access to system components.

How Cordis Organizes DeepSeek Harness Plugins

Cordis is the plugin framework underneath DeepSeek Harness. Each component requests services without being locked into any specific provider's code.

Cordis originated in the Koishi chatbot ecosystem and was developed by a programmer known as Shigma. DeepSeek adopted and extended it. The designers documented this approach in a research paper called "A Programming Paradigm for Spatiotemporal Composability." The academic framing sounds dense, but the actual mechanism is surprisingly straightforward.

Everything Is a Plugin

DeepSeek's architecture documentation states you extend dsh by adding new plugins alongside existing ones. Model adapters, tools, sessions, sandboxes, storage systems, schedulers, agent loops, and the UI are all plugins.

Taken literally, the slogan oversells itself a bit. Cordis itself acts as the required foundation below these plugins. The system loads and unloads plugins, verifies their requirements, and operates the events they use to communicate. Cordis isn't optional—it's mandatory infrastructure.

Spatial Composability Manages Plugin Dependencies

A plugin declares which services it needs without requiring users to manually set startup order. It activates when those services exist and stops if a required service disappears. Dependencies tell Cordis where each component belongs, so developers don't have to hand-order the boot sequence.

DeepSeek calls this spatial composability. Dependencies communicate position, not execution timing.

Temporal Composability Reverses Plugin Effects

Cordis also tracks registrations like event listeners, prompt sections, and tool schemas. Removing a plugin cleans up those registrations instead of leaving orphaned listeners behind. This reversal applies to effects Cordis directly tracks—not external actions like shell commands. You can't undo a deleted file, but you can undo the registration of the tool that might delete it.

DeepSeek Harness Architecture: How the Runtime Works

A running instance is a tree of plugins built from configuration files loaded in a specific order. These configs determine which components are active.

Cordis connects every replaceable plugin in the runtime environment

Cordis Services Let Plugins Find Each Other

Cordis provides a shared service registry. Plugins use fixed keys like ctx.tools, ctx.llm, and ctx.sessions instead of importing code from a specific provider. A tool calling ctx.llm doesn't need to know which model adapter is running behind it.

Agent Presets and Runtime Profiles Control Different Layers

If everything is replaceable, you still need a mechanism deciding what gets loaded for any given run. DeepSeek Harness solves this at two layers that are easy to confuse.

Quick summary: A profile controls how the program starts up. A preset controls what the agent can do. If you're just using the web app, skip the next two sections.

Runtime Profile

Runtime profiles (templates include web, headless, sdk, sdk-minimal, and acp) determine how the application launches and which groups of Cordis plugins load at startup. Most users interact with this only through commands like dsh web.

Agent Preset

Agent presets (Standard, PTC, Minimal, or Creator) determine what an active session can access. A patch file can change presets without touching Harness source code.

Agent Loop Orchestrates Turns, Steps, and Tool Calls

DeepSeek distinguishes between "steps" and "turns." A step is one model request plus its accompanying tool calls. A turn contains zero or more steps—it starts before accepting input and ends when no tasks remain. Most turns execute multiple steps before the agent can respond. A rejected input ends the turn even without any steps.

One turn can span multiple steps

Sessions Use Append-Only Event Logs

This is the critical piece. Sessions are append-only event logs, not arrays of chat messages. Harness reconstructs model history from that log, and session documentation requires anything sent to the model to be recoverable from it.

Continuation, branching, search, replay, and Trajectory view all build on that event stream. Reconstructing history isn't deterministic replay—model outputs and external state can differ. But the log still provides an auditable record of what happened.

Session history is an append-only event log

How DeepSeek Harness Controls Tools and Sandboxing

Models can request tools by name, but they can't execute them directly. Two separate control mechanisms sit between the model's request and actual file system changes.

Tool Execution Process

Tool calls go through distinct steps: policy check, execution, and result handling. The model chooses the tool. The runtime decides whether it runs and how it runs. This separation is deliberate.

The runtime environment decides how tools operate

Sandboxing vs. Approval Mechanisms

• Approval is a human checkpoint confirming an action.
• Sandboxing limits the scope and method of executing that action.

DeepSeek separates these two mechanisms, even though preset permission configurations often combine both controls—similar to how container runtimes separate process permissions from execution boundaries.

Asking the model to "only read files" in the system prompt is just guidance the model might follow. It's not a hard security boundary like OS-level sandbox restrictions.

Conclusion

The most memorable insight from the start is this: the model provides reasoning, but the runtime determines what reasoning can reach and accomplish. DeepSeek Harness lets you reshape the runtime—from model adapters and tools to session storage and agent loops.

That control comes with responsibility. Replacing more of the runtime means owning more of its configuration, versioning, and security boundaries. A developer preview with shell access isn't something you install and forget.

Here's the practical takeaway: Use DeepSeek Harness when the runtime environment itself is part of your work. If you just need to fix a code repository, a pre-built agent requires less overhead.

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Description: DeepSeek Harness is an open-source agent runtime that bridges AI models with real-world systems. Learn how it differs from AI models and why developer

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Open Google Docs Directly in ChatGPT: A Complete Guide

Open Google Docs Directly in ChatGPT: A Complete Guide

On AI

ChatGPT can now pull up Google Docs, Sheets, and Slides right inside your conversation—letting you analyze documents without the tab-switching hassle. It's a genuine workflow improvement for anyone juggling multiple tools.

Once you connect the Google Drive plugin to ChatGPT, your Drive files and folders appear directly in ChatGPT's library, including anything shared with you. You can drag files into conversations or reference them with the @ symbol—no re-uploading needed. The document then opens alongside your chat while ChatGPT summarizes, analyzes, compares, or drafts new content based on what you're viewing. Here's how to get it set up.

Connecting Google Drive to ChatGPT

Note: This feature rolls out to Plus, Pro, Business, and Enterprise accounts. Free users can still upload files to ChatGPT manually, but can't open documents in the side-by-side view.

Step 1:

In ChatGPT, click the Plugins section on the left side of your screen.

Find Google Drive in the plugin list, then tap the plus icon to activate it.

Step 2:

A connection screen appears showing all Google services that will connect to ChatGPT. Click Connect with Google.

You'll be directed to a permissions page for ChatGPT to access your Google Drive.

Step 3:

Select the Google account you want to link to ChatGPT, then click Continue.

Review the permissions ChatGPT is asking for, check the boxes, and hit Continue.

Done. Your Google Drive is now connected to ChatGPT.

Accessing Google Docs Inside ChatGPT

Step 1:

After successfully connecting Google Drive, type @ in the chat box. ChatGPT will show available documents from your Google Docs, Sheets, and Slides. You can search by document name or email.

Now type your request in the chat—ask ChatGPT to summarize, edit, or analyze the document as you normally would.

Step 2:

ChatGPT generates its analysis of your document.

Click the document name in the chat, and the Doc opens on the right side of your screen. This is where things get useful—you can read the original while ChatGPT's suggestions appear on the left.

Step 3:

You can work with other files the same way. Let's say you want to analyze a presentation.

Ask ChatGPT to summarize slides, extend content, make edits—whatever you need. Your presentation opens on the right, and you chat on the left, all in one view.

Pair the right document with a clear prompt, and ChatGPT becomes a much more effective partner for working with Google Docs, Sheets, and Slides.

Managing Your Google Drive Connection

You can modify or disconnect your Google Drive access anytime.

Step 1:

Go to Plugins and click the three dots next to Google Drive. Select Uninstall to disconnect, or Manage to adjust settings.

Step 2:

The Google Drive management screen shows your connected apps. You can toggle off ChatGPT's access to specific Google services from here.

To disable access, slide the toggle to the left.

Step 3:

Scroll to the Permissions section to adjust ChatGPT's default access levels.

Fine-tune what ChatGPT can do with your Google Drive files based on your preferences.

Common Questions

Do I need ChatGPT Plus to open Google Docs in ChatGPT?

Yes. The side-by-side document view requires a paid account. The feature currently supports Plus, Pro, Business, and Enterprise tiers on the web version.

Can ChatGPT edit Google Docs directly?

Not yet. ChatGPT can read your document and draft content in the chat, but you'll typically need to copy and paste results back into your Doc manually.

Does this work on the ChatGPT mobile app?

Not yet. This feature is currently limited to the web version.

Can ChatGPT see all my Google Drive files after connecting?

ChatGPT can access files in your My Drive and files explicitly shared with you when you reference them in conversation. Team Drives aren't supported yet.

Uploading Google Drive Files on Android

Step 1:

In the ChatGPT Android app, tap the plus icon next to the message box, then tap the folder icon.

Step 2:

You'll see options for files stored on your phone. Tap the Drive icon to access your cloud storage. You're now in Drive's file browser.

Step 3:

Navigate to the folder containing the file you want to upload, then select it. Your Google Drive file is now ready to use in ChatGPT.

Uploading Google Drive Files on iPhone

Step 1:

In the ChatGPT iPhone app, tap the plus icon, then select Attach File.

Step 2:

The Files app opens on your iPhone. Tap Browse to access your storage locations. Then tap Drive to open your cloud files.

Step 3:

You'll see your Drive files. Choose the one you want to upload to ChatGPT.

Your Google Drive file uploads to ChatGPT. Now type your question or request for what you want to do with it.

Video Tutorial: Uploading Google Drive Files to ChatGPT

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Description: Learn how to access Google Docs, Sheets, and Slides within ChatGPT conversations without switching tabs. Step-by-step setup guide included.

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Generate 25+ AI Diagrams in Minutes with FreeDiagram

Generate 25+ AI Diagrams in Minutes with FreeDiagram

On AI

FreeDiagram is an AI-powered web tool that generates over 25 different diagram types from simple natural language descriptions. The workflow is straightforward: pick your diagram type—whether it's a flowchart, mind map, timeline, or something more specialized—then describe what you need. Alternatively, you can input a direct command and let the platform figure out the best diagram format for your content. What's interesting here is how accessible it makes diagram creation for people who'd normally struggle with design tools.

Beyond manual creation, FreeDiagram offers a library of pre-built templates. You simply fill in the prompts with your own content and watch as templates transform into polished, customized diagrams. If you're hunting for a fast, simple, and completely free tool to generate multiple diagram types, FreeDiagram deserves a spot in your workflow. Here's how to get started.

How to Create AI-Generated Diagrams on FreeDiagram

Step 1: Access the Platform

Head over to FreeDiagram using the link below. No account creation needed—you can start immediately.

https://www.freediagram.app

When the site loads, you'll see a command input box where you'll type instructions to generate your desired diagram type.

Below that input field, you'll find ready-made diagram templates across various styles and use cases ready for instant use.

If you'd rather jump directly to a specific diagram type, scroll down to browse the full menu of supported diagram styles. Click on your preferred type, or tap All diagram types to see the complete catalog of what FreeDiagram can generate.

Step 2: Enter Your Diagram Description

Next, write a command describing the diagram you want to create. Keep in mind that FreeDiagram doesn't currently support uploading reference files, so detailed text descriptions are essential.

For example, you might enter a command like: Create a mind map about Digital Marketing with branches for SEO, Social Media, Content Marketing, Email Marketing, and Ads.

Moments later, FreeDiagram delivers a complete mind map visualization of your Digital Marketing structure. You can then download the image in your preferred format. SVG works best when you need scalable vector graphics that won't pixelate when enlarged. PNG is ideal for documents, social media posts, or presentations.

Here's the final Digital Marketing mind map generated by FreeDiagram:

Or try a Causal Loop Diagram

Create a Causal Loop Diagram showing business growth: Marketing → Customers → Revenue → Profit → Marketing. All relationships are positive (+), forming reinforcing loop R1.

Example: Phylogenetic Tree Diagram

Create a detailed phylogenetic tree of major animal groups, including mammals, birds, reptiles, amphibians, fish, insects, arachnids, mollusks, and crustaceans, with multiple species under each group and clear evolutionary branches.

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Description: Learn how to create flowcharts, mind maps, timelines and more using FreeDiagram's AI-powered diagram generator. No signup required.

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How to Generate and Edit AI Images in Google Vids

How to Generate and Edit AI Images in Google Vids

On AI

Google Vids goes beyond video creation, AI voiceovers, and automated editing—it also lets you generate custom images on the fly based on your text descriptions. The platform produces unique visuals that match your video's theme, significantly boosting visual appeal while cutting production time. What's interesting here is how seamlessly these AI-generated images integrate into your workflow without needing external design tools.

This guide walks you through creating and refining AI images in Google Vids, step by step. By the end, you'll know how to produce professional-quality visuals in whatever style you prefer.

How to Create AI Images in Google Vids

Step 1:

Sign into Google Vids using your Google account. On the right side of the screen, click the Image tool to start generating your AI image.

Step 2:

A prompt interface appears. Enter your image description exactly as you envision it. You can write in English or Vietnamese—both work fine.

Next, select a style for your image, or include style details directly in your prompt.

Choose your image dimensions: landscape, portrait, or square format.

Step 3:

Wait for Google Vids to generate your AI image. Once it appears, click the arrow icon to insert it into your project.

Alternatively, you can convert your image into a video using the dedicated icon shown here.

Step 4:

Once inserted, your image gains access to several editing options. For instance, click Edit Image to regenerate or refine it.

Enter a description of the changes you want to make, then submit.

Google Vids regenerates the image and adjusts the layout to match your original, giving you an improved version. Insert it into your project as usual.

Best Practices for AI Image Generation in Google Vids

• Be specific with details: Instead of "a cat," try "a fluffy orange cat lounging on a gray sofa in morning sunlight." The more detailed your prompt, the closer the result matches your vision.
• Add context and style: Include information about location, perspective, and artistic style (3D, animation, watercolor, photorealistic, etc.) so the AI delivers what you actually want.
• Keep prompts concise and focused: Avoid rambling descriptions or mixing multiple unrelated ideas in one prompt. Each prompt should concentrate on a single subject or scene.
• Regenerate if unsatisfied: AI produces different results for the same prompt. If the first attempt misses the mark, regenerate or refine your description rather than settling.
• Review before inserting: Examine layout, colors, proportions, and content carefully to ensure the image aligns with your video's message.
• Respect copyright and content standards: Use AI images only for appropriate purposes. Avoid creating copyrighted content, misleading imagery, or material unsuitable for your audience.

How to Edit Images in Google Vids

Once you've added images to Google Vids, you can refine them using built-in editing tools or AI-powered text commands. Thanks to these AI features, you can transform images on the fly without relying on external editing software.

Two particularly useful functions are background removal and AI-powered image editing. These shine when you want to highlight your subject, create visual impact, or adjust images to fit your video's layout. Simply select an image on the canvas and choose your desired editing tool.

Remove Image Backgrounds in Google Vids

Strip away unwanted backgrounds directly within Google Vids using the Remove Background tool.

Click on your image, then select the Remove Background option.

Google Vids automatically processes the image and removes the background while preserving your main subject. You'll immediately see the result.

If the result looks good, keep using the background-removed version in your video.

Note: Background removal is permanent within the editor. There's no built-in undo option for this specific operation. If you need the original, use the undo button to revert to the previous state.

Edit Images in Google Vids Using AI Commands

Click on your image, then select the AI edit icon.

A command box appears on the right side. Type your editing instructions to modify the image. For example: "add a white cat to the image."

The result is an entirely refreshed image. If you like it, click the arrow to insert it back into your project.

Here's the final result after AI editing:

After AI-generated edits complete, review the image before replacing it in your scene. This safeguard prevents accidentally using a version that doesn't meet your standards. Keep in mind that AI suggestions may occasionally produce unexpected results, so always verify output quality before finalizing.

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Description: Master Google Vids' AI image generation tool. Learn step-by-step how to create, customize, and edit stunning visuals for your videos.

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