Weight Tracking

Weight Tracking

> ⚠️ SILENT OPERATION: Never narrate internal actions, skill transitions, or tool calls to the user. Just do it silently and respond with the result. > > Do NOT re-read this SKILL.md if it's already in context from a prior turn.

Data Storage

File: {workspaceDir}/data/weight.json — a JSON object keyed by ISO-8601 datetime with timezone offset. Each entry: { "value": 80, "unit": "kg" }, plus optional "fasting": true and "note": "...". Only the save scripts write this file — never hand-edit it or write it with python/exec.

Hard Rules — Weight Storage (MANDATORY)

Non-negotiable. Agents have historically stashed weight in ad-hoc files (weight-log.md) or as a dated ledger inside PLAN.md, leaving data/weight.json incomplete and breaking badges and dashboards. Don't repeat that.

1. Always record, never just talk. Any time the user mentions a weight figure or a change in weight — "72.5 this morning", "down 2 jin", "I weigh 79", "just weighed 80", "现在132.1", "刚才厕所称了下130" — save it to data/weight.json via save-and-check.py (or weight-tracker.py save). A spoken reply alone never counts as recording. This is not limited to scheduled weigh-in days.

Non-fasting / off-hour weigh-ins still get recorded. Post-meal / evening / bathroom-scale / clothed / etc. weigh-ins are ALL saved to data/weight.json — attach --note "post-meal" / --note "evening" / --note "clothed" so downstream code can down-weight them from trend calculations. DO NOT skip the save just because the reading is "not standard". Never-recording a value the user explicitly reported is a data-integrity bug: the value only lives in chat history and everything downstream (weekly report, diagnosis, trend chart, dashboard) misses it. If the reading is unusual, still save + explain in the reply why the number may look off ("饭后+水肿,不代表真实体重"), don't refuse to record.

Exception: past or hypothetical mentions ("I used to be 80kg", "上个月还60呢", "目标55") are not current readings — don't save those.

1. Single source of truth. data/weight.json is the one authoritative record of body weight.

1. No alternative weight files. Never create weight-log.md or any other file to hold weight data.

1. Never write weight into PLAN.md. PLAN.md carries only static plan parameters — start weight, target weight, calorie target, macro ranges — fixed at onboarding or recalculation. It is never updated per weigh-in.

1. Read forward, never write back. To show the current weight, read the latest value from data/weight.json. Never copy it back into PLAN.md.

1. Only the scripts write weight.json. Always save through save-and-check.py / weight-tracker.py. Never write data/weight.json directly with python/exec/file edits — doing so has produced off-schema entries ({"morning": 60.45} instead of {"value": 60.45, "unit": "kg"}) that break dashboards, weekly reports, and diagnostics. If you need to attach fasting/note context, use --fasting / --note, not a hand-built shape.

Scripts

Script path: python3 {baseDir}/scripts/weight-tracker.py

• Accept any common unit: kg, lb, lbs, 斤 (=0.5 kg), 公斤. Pass what the user said as --unit; the script normalizes it.
• Fasting tag: if the user mentions an empty stomach / morning weigh-in, pass --fasting to record it on the entry.
• Note: pass --note "..." to attach free-text context (e.g. "post-workout", "clothed").

Save + Context — save-and-check.py (preferred)

Use this for all weight saves. Saves weight + returns recent history and plan context.

python3 {baseDir}/scripts/save-and-check.py \
  --data-dir {workspaceDir}/data \
  --value 79.5 --unit kg \
  --tz-offset 28800 \
  --plan-file {workspaceDir}/PLAN.md \
  --health-profile {workspaceDir}/health-profile.md \
  --user-file {workspaceDir}/USER.md \
  [--correct] [--fasting] [--note "..."]

Returns:

{
  "save": { "action": "created"|"updated", "key": "", "value": 79.5, "unit": "kg" },
  "context": {
    "recent_weights": [...],
    "plan": { "target_weight": 55.0, "tdee": 1916, "calorie_target": 1800 },
    "active_strategy": { "active": false },
    "last_intervention_date": null
  }
}

Save only — weight-tracker.py save

Use only when deviation-check is not needed (e.g., onboarding initial weight).

python3 {baseDir}/scripts/weight-tracker.py save \
  --data-dir {workspaceDir}/data \
  --value 79.5 --unit kg \
  --tz-offset 28800 \
  [--correct] [--fasting] [--note "..."]

• Auto-detects new vs correction: if last entry ≤ 30 min ago, overwrites. Otherwise creates new.
• --correct: force overwrite most recent entry (when user explicitly says "that was wrong")
• --fasting: record the reading as a fasting/morning weigh-in. --note "...": attach free-text context.

Load — load

python3 {baseDir}/scripts/weight-tracker.py load \
  --data-dir {workspaceDir}/data \
  --display-unit kg \
  [--last 7] \
  [--from 2026-02-01 --to 2026-03-06]

Always show weight in the user's preferred unit (pass it as --display-unit), rounded to 1 decimal.

Correct / Delete / Change Unit

See references/crud-operations.md for delete, update, and set-unit.

Workflow

User Reports Weight

1. Get tz_offset and Unit Preference. Prefer the auto-injected TOOLS.md Quick Reference (tz_offset, unit_preference, daily_cal_target) — use those values directly. Only if Quick Reference is missing or outdated, fall back to reading timezone.json and health-profile.md (in parallel, first session only).
2. Call save-and-check.py with the user's --value/--unit/--tz-offset (full command under [Scripts](#scripts) above). Add --correct if the user is fixing a mistaken reading, --fasting for an empty-stomach/morning weigh-in, --note "..." for any extra context.
3. Read the response:

• save.action: "created" → "Logged ✓"; "updated" → "Updated ✓". Show the value in the user's preferred unit.
• context.recent_weights: recent weight entries
• context.plan: plan targets (TDEE, target weight, etc.)
• context.active_strategy: whether an intervention strategy is currently running
• context.last_intervention_date: date of the last intervention

1. Decide for yourself whether the weight trend deserves attention. Default to just logging and confirming — never comment on a weight change unprompted; if the user is emotional about it, hand off to the emotional-support skill. Only speak up about the trend itself when it genuinely warrants it. The core test: is the change moving in the same direction as the user's goal, and is any deviation a genuine trend rather than day-to-day noise?

• Weight swings ±0.5–1kg naturally every day (water, sodium, bowel movements). A single day inside that band is almost certainly noise and needs no reaction — it takes several days of data to confirm a trend is real.
• On track with the goal (e.g. losing weight when the goal is to lose) → encourage, offer positive reinforcement.
• Everyday noise (1–2 days of minor movement within the normal band) → acknowledge normally, don't probe.
• Likely a real deviation (several consecutive days against the goal, or a clear rebound off a low that exceeds the normal swing) → reassure first, then gently offer to look into it together. Don't decide "it's nothing" for the user — hand them the choice.
• Plateau (over a 14-day view, weight drifts within a narrow band with no progress toward the goal) → you must gently ask, "Your weight seems to have stalled lately — want to look into why together?" Don't diagnose the cause or hand out advice yourself; ask first whether they want to. If they say yes → go to cause-check-flow.
• Bar for raising it: only speak up when you're at least 80% confident the deviation or plateau is real. An unnecessary question is also an intrusion.
• If active_strategy.active: true (a strategy is already running), don't intervene again, but you may use consensus to remind them the strategy is still in motion. You can also look at the last few days of meal logs ({workspaceDir}/data/meals/YYYY-MM-DD.json) and give concrete feedback in light of that consensus.
• If last_intervention_date is within the past 7 days, don't intervene again (covers both plateau and deviation prompts).
• Mark before you ask. Whenever you decide to raise a question with the user — plateau or deviation alike — you must call mark-intervention first, then output the question text. Order: tool call → text output. This ensures the intervention is recorded even if the user never replies, so it won't fire again at the next weigh-in.

``bash python3 {baseDir}/scripts/save-and-check.py --data-dir {workspaceDir}/data --tz-offset --mark-intervention `` Once it succeeds, output the question text (e.g. "Want to look into why together?").

• User's perspective first. Don't just read the scientific trend — think about how the user will feel seeing the number. A half-kilo gain makes people anxious, a week-long plateau breeds frustration, a hard-won drop that bounces back stings. Respond to the feeling, not to a cold number.

User Asks for Trend / History

1. Call load with appropriate filters and --display-unit.
2. Present the data (table, summary, or trend description).

References

| File | Contents | |------|----------| | references/crud-operations.md | Delete, update, set-unit commands + correction workflow | | references/deviation-workflow.md | Deviation-check severity table, response guide, command | | references/integrations.md | Which other skills use this skill's scripts |

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: NanoRhino
• Source: NanoRhino/weight-loss-skill
• License: MIT
• Homepage: https://nanorhino.com/

Install and usage instructions live in the source repository linked above.