DeepSeek Harness coding agents handling complex tasks often lack explicit engineering workflows and traceable evidence. The fullstack-expert plugin provides a Cordis-native workflow and safety layer for this, aiming to make agent operations, planning, and verification transparent and controllable.

Plugin Positioning

This is a Cordis-native, evidence-driven full-stack engineering specification for DeepSeek Harness agents. It does not introduce a new agent framework, shell, file system, browser, or database client; instead, it registers native capabilities to add a layer of engineering discipline to existing Harness workflows.

Core Features

  • Cordis-native workflow and safety layer: Serves as a native workflow and safety layer for DeepSeek Harness coding agents.
  • Repository inspection and planning: Supports repository inspection and vertical-slice planning.
  • Sensitive operation boundaries: Clearly defines the scope of sensitive operations.
  • Evidence recording: Records fresh verification evidence and ensures that verification evidence must come from native Harness checks, not self-attestation.
  • Deterministic runtime seam: Provides a FullstackExpertRuntime state seam for managing phases, tasks, evidence, and compact event facts.
  • Embedded skills: Registers embedded narrow skills through native ctx.skills.
  • Permissions and approval: Includes permission categorization and provides an approval-aware gate before execution; sensitive operations are delegated to native Harness approval, failing closed if unavailable.
  • Supabase detection: Optional, read-only Supabase project evidence detection.
  • Provider neutrality: Does not select or hard-code LLM adapters during operation.

Installation and Enablement

Use the DeepSeek Harness CLI to install this plugin. The installation command activates its declared patch layer.

dsh plugin --profile web add git+https://github.com/adithya-hmt/fullstack-expert.git#v0.1.1
dsh --profile web --dump-config
dsh --profile web

Replace web with the actual name of your profile.

Typical Usage

  1. Request a task: Ask the agent for a feature, bug fix, code review, refactor, or application build.
  2. Vertical-slice planning: For substantial work, the agent should invoke fullstack_plan. This action performs repository inspection, states assumptions/unknowns, and uses native tools to implement vertical slices.
  3. Structured checks: Use fullstack_check to perform structure, command, or Supabase checks and record non-verification review facts.
  4. Verification for completion: Work may only be completed when native verification evidence from Harness is recorded as passing and no relevant failures exist.

Notes and Scope

  • No additional components introduced: The plugin does not introduce a second agent framework, shell executor, file system backend, browser driver, database client, or model provider. It reuses existing capabilities exposed in the Harness composition.
  • Browser verification: Browser verification currently consists of guidance plus evidence recording until stable browser tools are integrated.
  • Supabase operations: Supabase operations are limited to detection and recommendations; migrations, linking, login, push, reset, pull, function deployment, and external writes remain explicitly sensitive operations.
  • Configuration management: Provider configuration should remain outside this package. Use the Harness provider/model settings surface to configure existing OpenAI-compatible CLI agents (for example, provider: <your proxy adapter>, model: GPT-5.6 Max).
  • License: The plugin implementation follows the MIT license.

Summary

fullstack-expert aims to make coding agents “show their work.” Through native Cordis capabilities and explicit workflows, it standardizes repository inspection, vertical-slice planning, sensitive operation boundaries, and verification evidence, making it suitable for developers who need rigorous engineering processes in DSH.