dsh-exit-code-lens

A DeepSeek Harness plugin that stops the agent from "investigating" commands that worked.

中文：很多命令用非零退出码表示「答案」而不是「失败」：grep 没搜到返回 1，diff 有差异返回 1，test 为假返回 1。dsh 会把这类结果标成 [exit code: 1]、卡片变红，系统提示词又要求模型「每个 bash 结果都检查 exit code，出错先排查」，于是模型反复重跑、核查，白白浪费轮次和 token。这个插件在结果里补一行说明，告诉模型这不是错误，可以继续。

The problem

dsh's bash tool appends [exit code: N] to every non-zero result, and its system prompt says "Check the [exit code: N] marker on every bash result; investigate failures before moving on." So when grep -rn TODO src finds nothing, the model treats "no matches" as a failure and goes digging: re-running the search, listing directories, checking the file exists.

Community reports:

• Discussion #1884: a third-party eval where an exit-1 loop roughly doubled requests (61 vs 32) on the same task.
• Discussion #8403: 7 of 56 tool results in one session were exit 1, all from how the command was written, not real errors.

What it does

After every bash call it checks the command and exit code. When the status is a known answer, it adds one line above the marker:

(no output)
[exit-code note: grep exits 1 when no line matched. Nothing failed; the answer is "no matches".]
[exit code: 1]

The [exit code: N] marker stays the last line, so the terminal card still shows the exit pill. It also adds one sentence to the system prompt so the model knows to trust the note.

Built-in rules (exit 1 only):

Command	Meaning of exit 1
grep egrep fgrep zgrep rg ag ack git grep	no matches
diff cmp git diff --exit-code/--quiet	inputs differ
test [ [[	condition is false
which type command -v hash	not installed
pgrep pidof	no such process
git merge-base --is-ancestor	not an ancestor
jq -e	last output false/null

When it stays quiet

It is deliberately conservative. No note is added when:

• anything was written to stderr (grep pattern missing-file exits 2 and prints an error — that is a failure);
• the exit code is anything other than the rule's code (e.g. grep 2, diff 2);
• the deciding command is not the last one: grep x f | wc -l, grep x f || echo none, cmd &;
• the command uses control flow, subshells or heredocs (if, for, ( … ), <<EOF);
• the call was killed, timed out, or failed to run.

Leading VAR=x, env, sudo, timeout N, nice -n N and redirects like 2>/dev/null are looked through. For pipelines or cd x && grep … the note adds "(Assuming the status came from the last command.)"

Install

dsh plugin --profile <profile> add github:YanYunCY/dsh-exit-code-lens

Requires Node ≥ 24.9. Tested with dsh 0.2.1-rc.5. No build step, no runtime dependencies, no network access.

Configure (optional)

# $DSH_HOME/profiles/<profile>/cordis.patch.yml
- id: exit-code-lens
  config:
    tools: [bash]          # tool names to annotate
    prompt: true           # add the one-line system-prompt hint
    rules:                 # your own tools, checked before the built-ins
      - command: mytool
        subcommand: check
        codes: [3]
        note: "{cmd} exits {code} when the check is still pending. Nothing failed."

Cost

One extra line per matching result, and one sentence (~70 tokens) in the system prompt. The prompt sentence is static, so it does not break the KV cache between requests. Set prompt: false to drop it.

What it does not do

• It does not hide the exit code or turn the card green. The model still sees the real status.
• It does not cover PowerShell or Windows cmd yet.

License

MIT