Per-session policy overrides (sandbox/mode, approval/policy) never crossed the delegation boundary: a spawn child of a read-only-switched parent ran under the wider deployment default, and a fork child missed any switch made after its seed boundary — delegation was a bypass channel for a user's tightening. The in-process driver now snapshots the delegating parent's override chain and stamps it onto the child through the canonical write paths (SandboxPolicyService.inheritOverride / ApprovalService.inheritOverride), anchored inside the child's first turn via a one-shot agent/prompt-submit listener: turn-enclosed (durable), ahead of the first request (an inherited 'never' reaches the child's first system prompt), and positioned after any stale fork-seed switch so the ordinary last-event-wins fold resolves it. Only overrides are copied — an unswitched parent stamps nothing and the child follows the live deployment default; both services are consumed opportunistically, so compositions without them delegate unchanged. Nesting composes by construction (each stamp folds the already-stamped parent log). Evidence: inheritance.spec.ts drives scripted-model children into the real dsh-fs-sandbox fence through the real write tool (disk-state + denial-marker assertions; spawn, stale-seed fork, grandchild, escalation fail-closed, and no-stamp guards), inheritOverride contract tests in both service suites, and the recorded subagent-sandbox-inheritance ACP snapshot (read-only preset → delegate → child denied, replayed keylessly). See .agents/notes/implemented/feature/2026-07-25-subagent-policy-inheritance.md.
DeepSeek Harness
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The DeepSeek Harness SDK is a plugin-based SDK for building agent harnesses.
Install
Install the dsh coding agent with one line — it needs git and Node ^22.19 || >=24, and offers to install pnpm if it is missing:
curl -fsSL https://raw.githubusercontent.com/deepseek-harness/deepseek-harness/master/scripts/install.sh | sh
It clones the harness to ~/.dsh/source, runs pnpm install, symlinks dsh into ~/.local/bin (offering to add it to your PATH), prompts once for your DEEPSEEK_API_KEY, and launches dsh; re-running it updates an existing checkout. Run from inside a checkout (sh scripts/install.sh) it reuses that checkout and skips the clone. The overridable DSH_* variables are documented in scripts/install.sh.
Development
This monorepo is built on the Cordis framework (vendored as source under vendor/), microkernel-style: everything is a plugin.
pnpm install
pnpm run test # vitest
# Agent demos require DEEPSEEK_API_KEY.
pnpm run demo:tui # full-screen TUI coding agent
pnpm run demo:headless "task" # one-shot coding agent
pnpm run demo:cordis # self-referential agent demo
pnpm run demo:acp # ACP server agent demo
For humans, start with the development guide for local setup, hooks, environment variables, and quality gates, then read the architecture design and documentation graph index before package work. Local context lives in packages/ and vendor/.
For agents, follow AGENTS.md.