Four review findings. Two are defects the previous two rounds introduced, which the existing tests did not catch: A backspace erased raw bytes, so one landing after an SGR reset ate part of the escape: `\x1b[31mabc\x1b[0m\b\bXY` left `\x1b[` and repainted the rest of the line with whatever the remainder parsed as. Backspaces now resolve over VISIBLE characters — a CSI sequence is one indivisible unit a backspace steps over on its way to the last printed character, so the surviving text keeps the color its run authored. The cwd normalizer popped a UNC share root: `\\server\share` with a `..` became `/server`, losing the separators too. A UNC path's server and share are its root, and Windows cannot climb above a share, so they are split off and the remainder collapses against that root. The other two are gaps the earlier fixes left: The render-site fallback row still passed the args-derived summary, so any terminal-declaring tool without its own keyed row (`terminal_send`) lost the contract's above-card description. It now prefers the description exactly as BashRow does. A settled call read `call?.cwd`, which cannot tell "the call omitted a cwd" from "the paging window dropped the call head". The second case has no cwd anywhere and the original call may have used an explicit workdir, so it now draws a bare `$` instead of naming the session workspace.
DeepSeek Harness
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DeepSeek Harness (dsh) is an open-source coding agent built on the DeepSeek Harness SDK.
It uses an architecture where everything is a plugin.
Install
Install dsh with one command:
curl -fsSL https://raw.githubusercontent.com/deepseek-harness/deepseek-harness/master/scripts/install.sh | sh
The installer requires git and Node ^22.19 || >=24, offers to install pnpm when it is missing, and prompts for a DeepSeek API key.
The installer keeps every checkout under ~/.dsh/source: the master clone at ~/.dsh/source/master and each install's staging checkout as a git worktree ~/.dsh/source/staging-<timestamp>. The stable symlink ~/.dsh/source/current points at the active staging worktree, and dsh in ~/.local/bin links to current/bin/dsh, so an upgrade repoints one symlink and the dsh on PATH never moves. Re-running the command adds a fresh staging worktree from an updated master and repoints current at it. See scripts/install.sh for alternate install locations and other options.
Use DeepSeek Harness
Web UI
For the recommended local interface, build the frontend after installation and after each update, then start the Web UI. Resolve the running checkout from the dsh launcher so the command holds regardless of which staging worktree is current (the launcher resolves through the stable current symlink):
dsh_bin=$(cd "$(dirname "$(command -v dsh)")" && pwd -P)/$(basename "$(command -v dsh)")
while [ -L "$dsh_bin" ]; do
link=$(readlink "$dsh_bin")
case $link in /*) dsh_bin=$link ;; *) dsh_bin=$(cd "$(dirname "$dsh_bin")" && cd "$(dirname "$link")" && pwd -P)/$(basename "$link") ;; esac
done
dsh_dir=$(cd "$(dirname "$dsh_bin")/.." && pwd -P)
pnpm --dir "$dsh_dir" run build && pnpm --dir "$dsh_dir" run build:web
dsh web
The Web UI is served at http://127.0.0.1:3080 by default.
TUI
Start the full-screen terminal interface:
dsh
Headless
Run one task, print the final answer, and exit:
dsh -p "summarize this workspace"
Why DeepSeek Harness
Built-in capabilities cover file reading, editing, and search; shell execution; reusable skills; task tracking; subagents and workflows; persistent sessions; and context compaction. The TUI also includes Plan Mode.
- Everything is a plugin. Models, tools, policies, storage, context management, and interfaces are composable Cordis plugins, so deployments can extend or replace behavior without forking the agent loop. See the architecture for the underlying design.
- Code Mode (opt-in). It exposes a
run_codetool and a generated TypeScript SDK; only program output re-enters model context. See Code Mode. - Self-referential Cordis tools are opt-in. They let the agent inspect its live runtime and mount or unmount plugins while it runs. See the Cordis tools.
Community
Follow DeepSeek Harness on Twitter for project updates.
Development
pnpm install
pnpm run test:coverage
Start with the development guide and read the architecture before changing packages.
For agents, follow AGENTS.md.
DeepSeek Harness is currently pre-release.