dsh-ponytail
Your agent adds a cache class, a config flag, and a factory for one product. This
plugin makes it stop and write the one line that works instead. The ladder:
question whether the thing needs to exist, reuse what is already in the repo, then
the standard library, then the platform, then an installed dependency, then one
line. Stop at the first rung that holds. Adapted from
DietrichGebert/ponytail (MIT): "He
says nothing. He writes one line. It works."
What you get
- The ladder on every request. While any level except
off is active, the
mode-filtered ruleset joins the system prompt.
- Six skills the
skill tool can load, so they also appear as
/ponytail-review, /ponytail-audit, … in the composer: ponytail,
ponytail-review, ponytail-audit, ponytail-debt, ponytail-gain,
ponytail-help.
- Two ways to switch level. The model calls the
ponytail tool; you type
/ponytail <level> or just say stop ponytail.
- A settings card and a composer chip, so the level is visible without opening Settings.
- No unrequested abstractions, no boilerplate. Deletion over addition, boring
over clever.
Install
Install it as a bundle. dsh plugin add … mounts the row from the
package's own patch layer, which is what the settings editor can write to. A
row added with --patch is an overlay: it disappears at the next start, and
the Plugins card cannot save into it (the editor refuses a write an overlay
would win).
dsh plugin --profile web add --save-exact @maci0/dsh-ponytail@0.19.0
Pin an exact npm version. To upgrade, run the same command with the newer
version, then restart dsh web (bundle layers compose at boot).
Use it
/ponytail ultra -> Ponytail level: ultra (was full).
/ponytail -> Ponytail level: ultra.
/ponytail off -> Ponytail off (was ultra). Normal behavior.
Then ask for the work. This is the full example from the skill itself:
> Add a cache for these API responses.
`@lru_cache(maxsize=1000)` on the fetch function. Skipped custom cache class,
add when lru_cache measurably falls short.
Model side, the tool takes one optional argument: {"mode": "lite"} sets and
persists a level, and calling it with no argument reports the current one.
Typing stop ponytail or normal mode as an ordinary message has the same
effect as /ponytail off, and it lands on the turn that carried it. Only the
human's own words count: injected context riding the same event stream cannot
toggle the level, and the message must be the command, so "add a normal mode
toggle" is left alone.
Levels
| Level | Behavior | Persisted |
|---|
lite | Build what was asked, name the lazier alternative in one line. | yes |
full | The ladder enforced. Default. | yes |
ultra | YAGNI extremist: challenge the requirement before building it. | yes |
review | Over-engineering review; points at the ponytail-review skill. | no, session only |
off | No injection. Normal behavior. | yes |
The four persistable levels live in the ponytail settings namespace, so the
card, the chip, the tool, and /ponytail agree and the choice survives a
restart. review stays session-only because it is a review mode, not a level a
deployment should start in; the tool and the command still accept it. The card
and the chip show the level the host is using, so they show review, and any level
kept only for this session because the settings write failed, labelled as
session-only.
Lazy is not negligent. Understanding the problem, trust-boundary validation,
data-loss handling, security, and accessibility are never on the chopping block.
Configure
| Field | Default | Meaning |
|---|
defaultMode | full | Startup level. Must be off, lite, full, or ultra. |
The exported Config schema defaults the field, so a row that omits defaultMode
starts in full. The user's settings namespace overrides it once a level is chosen
in the card or by /ponytail. An invalid level fails while the plugin loads rather
than quietly doing the wrong thing: the loader validates the row against the
exported schema.
To set the startup level from the environment, override the row in your profile's
cordis.patch.yml with a !!js expression (same id, which replaces the row's
whole config):
- id: ponytail
config:
defaultMode: !!js process.env.PONYTAIL_DEFAULT_MODE ?? 'full'
Override the row this way; do not paste the bundle's insert of the
id: ponytail row into your profile's cordis.patch.yml: insert does not
dedupe ids, and a second row mounts the plugin twice.
How it works
The package declares dsh.bundle, so dsh plugin add appends it to
dsh.profile.bundles and the row in its own cordis.patch.yml applies as a layer.
The host half mounts through public Cordis extension points: systemPrompt.section,
skills.registerProvider, tools.register, commands.register,
loader/volatile-update (the settings document writes the row's volatile
defaultMode), session/event for the message switch, and webServer for
GET /ponytail/level, which answers { mode, source } (settings or session)
behind the connection trust fence. The browser half reads that route on every
settings change and every 5 seconds, draws its card into the public plugins.row.config slot from configForms, registers its
copy through locale.register, and draws its chip into conversation.input.left, so
this plugin needs no client change of its own.
The entry point is the built lib/index.js (declarations in lib/types/); bun run build regenerates it from src/. lib/client.js is hand-authored plain JavaScript:
the client module system serves it as a lazy-CJS factory on window.__ModuleLoader__
because the package exports ./client, and it is not built. Skills come from
skills/<name>/SKILL.md with frontmatter parsed by yaml; the provider takes its rank
and name grammar from @deepseek-ai/dsh-skill, projects disable-model-invocation,
user-invocable, and whenToUse, and settles on the lookup's abort signal. Tools use
defineTool from @deepseek-ai/dsh-tools and forward exec.signal. Only
skills/ponytail/SKILL.md is the source of truth for the ruleset; this README keeps no
second copy.
Limits
- It does not skip comprehension. The ladder shortens the solution, never the
reading. The skill says so in its own text.
- The level is process-wide. One prompt section, one namespace value: every
agent in the process shares it.
- External subagents ignore it. In-process children inherit the ruleset, but
subagent-claude-code and subagent-codex spawn their own CLI with its own
system prompt, and no harness extension point wraps a spawn.
- Two locales. The card and the chip ship
en and zh; any other locale
falls back through the service's own chain.
- Host source edits need
bun run build and a restart, because the Loader
loads lib/index.js and a bundle layer composes at boot.
- Browser-half edits need a page refresh.
- A level change is not a session event. A replayed session shows the ruleset
each request already carried.
Development
bun install # the client packages are optional peers and stay uninstalled
bun run build # tsc -p tsconfig.build.json -> lib/index.js + lib/types/
bun test # every tests/*.test.ts, no build step
bun run typecheck # tsc -p tsconfig.json
dsh loads plugins on Node ^22.19.0 || >=24.0.0; development and tests run on bun.
For local development, install the checkout into a profile with
dsh plugin --profile <name> add <path-to-checkout>.
The suite covers level normalization and filtering, the fake-host surface, the skills
provider, the client card, and a real Cordis composition mount next to the real skill
registry. To uninstall, run dsh plugin --profile web remove @maci0/dsh-ponytail; that removes
the dependency and the bundle layer together.
Attribution and license
MIT. Skill content and mode semantics: © DietrichGebert
(ponytail). DSH port: see LICENSE.
The six skills/*/SKILL.md files are verbatim copies, so they carry upstream's figures
and citations rather than this package's. /ponytail-gain therefore reports the original
five-task single-shot benchmark (80–94% fewer lines, 47–77% cheaper, 3–6× faster),
which upstream's own README has since revised to roughly 54% fewer lines, 20% cheaper
and 27% faster on its agentic benchmark.
