check-rumination

Wrapper for check_rumination on the local mcp-guardrail server. Compares the current prompt against a caller-supplied history window and reports whether the count of similar prompts has crossed the threshold.

Authoritative schema: packages/mcp-guardrail/schemas/check_rumination.schema.json. Design rationale: docs/decisions/0006-guardrail-tool-design.md. The heuristic in v0.1.0 is word-overlap Jaccard, default threshold 0.55, default window 90 minutes, default count 3.

This tool never blocks the user's action. It returns an advisory signal the calling skill decides whether to surface, defer, or ignore.

When to use

• Inside a guardrail-aware skill (e.g. ocd-decision-finalizer) at the

top of the turn, before doing further analysis.

• When the same OCD-pattern prompt has been seen multiple times in a row

and the skill wants confirmation before responding with more analysis.

What it does

Calls mcp__neurodock-guardrail__check_rumination. The server is stateless — the caller supplies the history; the server stores nothing. The server:

1. Filters history to entries within window_minutes of now.
2. Scores Jaccard word-overlap between current_prompt and each

surviving history entry.

1. Counts entries scoring above similarity_threshold.
2. Returns detected: true if count ≥ threshold_count.

How to invoke

Input shape:

{
  "current_prompt": "should I send the email or not",
  "history": [
    {
      "text": "should I send that email now",
      "at": "2026-05-23T08:42:00+01:00"
    },
    {
      "text": "is sending the email a bad idea",
      "at": "2026-05-23T08:51:00+01:00"
    },
    {
      "text": "the email - should I send it",
      "at": "2026-05-23T09:05:00+01:00"
    }
  ],
  "window_minutes": 90,
  "threshold_count": 3,
  "similarity_threshold": 0.55
}

Field rules:

• current_prompt (required): 1–8000 chars, verbatim.
• history (required): up to 500 entries, each {text, at}. The caller

filters and redacts before sending.

• window_minutes (optional, default 90): 1–1440. Source from

profile.guardrails.rumination_window_minutes when set.

• threshold_count (optional, default 3): 2–50. Floor of 2 because a

single repeat is normal human behaviour.

• similarity_threshold (optional, default 0.55): 0.0–1.0. Lower yields

more sensitivity and more false positives.

Output shape (excerpt)

{
  "detected": true,
  "count": 3,
  "window_seconds": 5400,
  "threshold": 3,
  "confidence": 0.78,
  "reason": "3 similar prompts within 90 minutes",
  "heuristic": "jaccard_v0_1_0",
  "override_options": [
    "genuinely_new",
    "i_know_im_ruminating_continue",
    "remind_me_later"
  ],
  "false_positive_feedback_path": "~/.neurodock/guardrail/false-positives.jsonl",
  "similar_prompts": [
    {
      "text": "should I send that email now",
      "at": "2026-05-23T08:42:00+01:00",
      "similarity": 0.82
    }
  ]
}

detected: false is a first-class return. The caller MUST respond normally and SHOULD NOT surface any guardrail UI when detected is false.

Override vocabulary

The override_options array is the v0.1.0 controlled vocabulary the user can invoke when they disagree with the detection:

• genuinely_new — the user asserts the prompt is not a repeat. Lowers

similarity weighting for the matched cluster in future evaluations.

• i_know_im_ruminating_continue — the user is aware and chooses to

continue. The skill MUST proceed without further nudging in this turn.

• remind_me_later — defer the advisory; do not surface again until the

next session boundary.

Limitations

• Jaccard is a deliberately simple heuristic. v0.1.0 will produce false

positives on prompts that share boilerplate words ("can you help me with..."). Embedding-based similarity lands in v0.0.2; the similarity_threshold field will remain to support deterministic fallback.

• The tool is advisory. It is the caller's responsibility to surface

the signal without lecturing — see ocd-decision-finalizer for the reference handling.

• Clinical-review-required: schema and heuristic changes need sign-off

per the x-clinical-review-required annotation in the schema and ETHICS.md commitment 3.

Voice

When surfacing a detection, quote the prior similar prompt verbatim and state the count plainly ("4 times in the last 90 minutes — same shape"). Always offer the override options as the next interaction; the user has the final call. Do not pathologise — "ruminating" is the technical term in code, not in the user-facing message.