Introduction¶

In DSH / Agent development, model gateways, proxies, or audit pipelines sometimes identify sessions via HTTP headers. dsh-session-header is a DeepSeek Harness plugin used to inject x-session-id into LLM provider requests issued by DSH, ensuring each call carries the corresponding harness session ID. Below is an introduction to its positioning, core behavior, installation methods, and verification methods.

What is it¶

dsh-session-header is maintained by homily707 and is licensed under MIT.

Its purpose is: to inject the x-session-id HTTP header into every LLM provider request issued by DeepSeek Harness, with the value taken from the harness session ID of the current call. The plugin operates at the provider layer, does not modify adapter code, and does not overwrite existing headers.

Core Features¶

• Injects x-session-id into LLM provider requests. The default value is the GenerateOptions.sessionId of the current call, with the session- branding prefix removed.
• Uses llm/stream waterfall and globalThis.fetch patching to override fetch-based adapters, such as llm-deepseek and llm-pi-ai.
• Propagates session context via AsyncLocalStorage, affecting only fetch within LLM call streams; concurrent sessions have header values parsed per call.
• Does not overwrite existing headers with the same name; comparison is case-insensitive.
• Supports configuring a fixed value for each call; if neither a session ID is available nor a fixed value is configured, no header is injected for that call.
• Restores the original fetch when the plugin is unloaded.
• Does not touch attributionHeaders().

Installation and Usage¶

The plugin requires the dsh CLI and Node ≥ 22.

As a bundle install:

dsh plugin --profile <name> add github:homily707/dsh-session-header

The package is plain JavaScript with no build scripts; it does not require the pnpm ≥ 10 build allowance. After installation, use --dump-config to view the configuration layer:

dsh --profile <name> --dump-config

Look for the layer marker in the output:

# == dsh-session-header

Confirm it exists and start:

dsh --profile <name>

If using a local checkout and loading via --patch overlay, you can insert the plugin configuration in the overlay. The following name must be the absolute path to the plugin’s entry file:

# my-overlay.yml
- insert:
    - id: session-header
      name: /absolute/path/to/dsh-session-header/index.js
      config:
        header: x-session-id
        # value: my-fixed-session-id

Then run:

dsh --patch ./my-overlay.yml

Configuration options:

• header: The name of the header to inject, defaults to x-session-id.
• value: Optional; if set, this fixed value is used for every call; otherwise, the session ID of the current call is used.

Typical Usage¶

Point the baseURL of a provider to a gateway that records request headers, or to an endpoint that echoes request headers, then start a session. The headers should look like:

x-session-id: ba104306-a748-4052-a6e3-ab60be2e4c1f

Use the session ID of the current call for each request; concurrent sessions parse header values per call via AsyncLocalStorage.

Use Cases and Notes¶

Suitable for DSH scenarios in gateways, proxies, or audit systems that perform routing, caching, or auditing based on session headers, and also for configurations that require overriding fetch-based LLM adapters.

Notes before use:

• The plugin runs with the privileges of the current dsh process; you should check the source code and license before installing.
• The plugin is provider-neutral and will not overwrite existing headers. The llm-deepseek adapter itself sends x-deepseek-harness-session-id; this plugin does not overwrite existing headers.
• If no session ID is available and no fixed value is configured, the call will not receive a header.
• The plugin patches globalThis.fetch at runtime and restores the original fetch upon unloading.

Links¶

• Community directory page: https://www.skillhub.cn/plugins/homily707/dsh-session-header
• GitHub: https://github.com/homily707/dsh-session-header