dsh-llm-repetition-guard

Usage

Install the package:

npm install dsh-llm-repetition-guard

Mount the plugin beside @deepseek-ai/dsh-llm-retry and add DEGENERATE_OUTPUT to the provider's retryableCodes:

- name: '@deepseek-ai/dsh-llm-deepseek'
  config:
    retryPolicy:
      mode: normal
      maxRetries: 2
      retryableCodes: ['EMPTY_RESPONSE', 'DEGENERATE_OUTPUT', 'RATE_LIMIT', 'SERVER', 'TIMEOUT', 'TRANSPORT']

- name: 'dsh-llm-repetition-guard'
  config:
    minOutputLength: 64
    windowChars: 1024
    unitLength: 8
    maxRepeats: 6
    checkReasoning: false

- name: '@deepseek-ai/dsh-llm-retry'

Why the explicit retryableCodes? The published @deepseek-ai/dsh-llm (through 0.1.0-rc.7) does not include DEGENERATE_OUTPUT in its default retryable set. Without it, the guard still truncates the degenerate stream and fails the request, but the loop treats the failure as terminal and the turn ends with an error. Add the code to make retry effective. A harness checkout that already carries the code in DEFAULT_RETRYABLE_CODES may omit the list.

The plugin has no other configuration. Thresholds are optional and default conservatively:

Key	Default	Meaning
minOutputLength	64	Minimum characters a block accumulates before detection starts.
windowChars	1024	Sliding-window characters retained per block; must be at least minOutputLength.
unitLength	8	Minimum character length of one repeated unit.
maxRepeats	6	Consecutive occurrences of one unit that trip the guard.
checkReasoning	false	Also guard reasoning blocks.

Verifying it works

Send a prompt that makes the model loop (or lower maxRepeats to 2 and use a degenerate output). The session log records the recovery:

• an llm/retry event whose failure.code is DEGENERATE_OUTPUT and whose failure.message names the repeated unit;
• the retried request completes normally and the turn ends completed.