dsh-compaction-policy
English | 中文
Stop DeepSeek Harness from condensing your conversation too early — and put the
trigger where you want it.
DSH automatically condenses older history when a conversation grows. On a lot of
models it starts much earlier than "80% full", and then it does it again a few
steps later. This plugin gives you that decision back: it does not edit any
config file, it adjusts the running compaction engine.
Is this for you?
Probably yes if any of these sound familiar:
- Your model's context window is smaller than roughly 330,000 tokens (most
local models, many hosted models).
- DSH condenses the conversation while the context ring still looks half empty.
- Right after a condensation the ring climbs back to the same place within a few
steps, so it happens over and over.
If you only ever use very large windows (e.g. 1M), the built-in behaviour is
already near 80% and you most likely don't need this.
Why it happens
Before each step DSH checks how large the next request would be and compares it
to this trigger:
trigger = min(window × 0.8, window − output reserve − 65536)
- window — the model's context window as DSH knows it.
- output reserve — how many tokens the request asks the provider to keep free
for the answer.
- 65536 — a fixed safety margin DSH always sets aside.
The second half of that formula is the catch: it subtracts a fixed 65,536
tokens regardless of how large the window is. Once the window is below about
330,000, that fixed subtraction is the tighter of the two limits, so it becomes
the real trigger:
| Context window | Where DSH actually triggers | Where 80% would be |
|---|
| 128k | ~62k (49%) | 102k |
| 150k | ~84k (56%) | 120k |
| 256k | ~190k (74%) | 205k |
| 1M | ~678k (68%) | 800k |
On very small windows (roughly up to 65k) the fixed margin swallows the whole
window: DSH then refuses to configure proactive compaction at all and only reacts
after a request is rejected for being too long — which throws away far more
history than a planned condensation would.
Why editing a config file doesn't help
In DSH 0.2 the compaction policy lives inside each agent preset, and a preset is
addressed as one whole definition: neither a profile config file nor a plugin's
own config layer can change a single field of it. The only way to write it to disk
is to replace the preset body — which pins your preset and stops it from picking
up DSH updates.
So this plugin doesn't touch any file. It changes the behaviour of the compaction
engine while DSH runs.
What it does
- Below your trigger it answers "nothing to do", so DSH's own check never runs.
- At or above it, the decision goes straight back to DSH — identical to the stock
behaviour.
- Emergency recovery after an over-long request and the manual
/compact command
are never touched.
- If anything inside the plugin goes wrong, it steps aside and DSH behaves exactly
as if the plugin weren't installed.
Which DSH versions this works with
DSH ships quickly, so the support line is stated rather than implied.
| DSH version | Status |
|---|
0.2.0-rc.2 | Verified — this release was developed and tested against it |
later 0.2.x / 0.3.x | Expected to work. The @deepseek-ai/* peers are open-ended, so a newer harness still installs and loads the plugin; if one of the internal seams it uses changes, it stops intervening instead of breaking your session |
earlier than 0.2.0-rc.2 | Not supported — the plugin wraps the per-agent-preset compaction engine, which only exists in the 0.2 line |
The machine-readable form of this table is the open-ended @deepseek-ai/* range in package.json, and the verified build is recorded there as dsh.verifiedWith.
Two checks tell you it is running on your build:
- Settings shows the Compaction policy / 上下文压缩策略 entry — the browser half loaded.
- Compaction fires near your configured ratio instead of around half-full — the host half is intervening (how to tell).
If it does nothing on your version, that is the designed failure mode rather than a crash: please open an issue with the output of dsh --version.
Last verified: DSH 0.2.0-rc.2, 2026-10-01.
Install
dsh plugin --profile <your profile> add github:zyd232/dsh-compaction-policy
Use the profile you actually run — desktop for the desktop app, web for
dsh web, or your own profile name. Then restart DSH: plugin rows are only
read at startup, so without a restart nothing changes.
You do not need to start a new conversation. Existing conversations are picked
up on their next step.
To remove it again:
dsh plugin --profile <your profile> remove dsh-compaction-policy
Where the settings are
Open Settings and look at the left sidebar: you will find a Compaction
policy entry alongside the built-in sections. The panel follows DSH's language
(Settings → General → Language) and defaults to English; Chinese is included.
Everything there is saved to DSH's normal settings document and applies
immediately — no restart needed. Each field also has a restore default button
that removes your override.
Settings
| Field | Default | What it means |
|---|
| Enable | on | Turn the plugin off to get DSH's stock behaviour back. |
| Routes | * | Which routes it governs: provider or provider/model, comma or space separated. * = every route. |
| Trigger ratio | 0.8 | Condense once the context reaches this share of the window. 0.8 = 80%, DSH's own default. |
| Output reserve (tokens) | 24576 | The margin kept free for the model's answer. DSH's own value is 65536; this is the knob that fixes the early trigger. |
Choosing values
General rule first, examples second.
- Trigger ratio — leave it at
0.8 unless you want extra safety. On a very
small window some people prefer 0.7.
- Output reserve — set it to the longest answer you realistically expect, plus
a little slack.
16384–32768 covers most chat and coding work; a model that
writes very long files may want more. Too small a reserve risks a request being
rejected because the answer had nowhere to go.
- Routes — narrow it when you only want some providers affected. For example
llama-cpp (only local models served by llama.cpp), ollama, openai, or
ollama/* to spell out every model of that provider.
With the default reserve of 24,576 the trigger becomes a clean 80% of the window
for every window above roughly 123k, and stays proportional below that.
How to tell it's working
Compaction is recorded in the session log. If you want numbers instead of a
feeling, take the request size immediately before a compaction and divide it by
the model's window: it should now land near your trigger ratio instead of the old
~50% mark.
Visually, the context ring should keep growing past the point where it used to
drop.
Limitations
- It moves the trigger only. How much history a condensation keeps and how
long the summary may be still come from DSH's compaction backend.
- Very small windows stay unsolvable. If the window cannot hold the request
itself (the fixed system prompt plus tool schemas), no policy helps. DSH's
backend refuses to configure proactive compaction for such a route, and this
plugin deliberately leaves that alone instead of retrying forever.
- It uses DSH internals. It finds the running compaction engine through DSH's
service API (
agentPresets.serviceFor(…, 'compaction')) and wraps its
compactIfNeeded method. If a future DSH renames that service or changes that
signature, the plugin needs an update — until then it simply does nothing rather
than misbehave.
- Languages. The panel and this document ship in English and Chinese and
follow DSH's language setting; more languages are welcome as contributions.
- Compatibility. The
@deepseek-ai/* peer ranges are intentionally open-ended
(>=0.2.0-rc.2, no upper bound), so a future harness release can never prevent
the plugin from installing or loading.
