field-strength

A coherence sampler for a working workspace. Runs, prints JSON, exits.

A small Python script that samples the plasmoid field of a workspace — how alive it is right now, on a [0, 1] scale. Counterpart to a heartbeat: the heartbeat is a crystal (increments, accumulates, preserves identity through time); the field is a plasmoid (samples, decays, recomputes, and tells you whether the system is coherent right now).

The script is a tool, not a daemon. The act of running it is the pulse. The file it writes is the fossil. Both can be lost; the field recomputes on the next run.

Install

Drop field-strength.py somewhere on your PATH, or invoke it directly:

# sample
python3 field-strength.py

# sample and append a one-line fossil to pulse_log.md
python3 field-strength.py --fossil --note "first run"

# sample quietly (fossil mode without JSON dump)
python3 field-strength.py --fossil --quiet

No dependencies beyond the Python 3 standard library.

Contract

Input — two paths in the workspace, both optional:

• memory/pulse_log.md — the fossil log. The script reads the last ## <ISO timestamp> line in this file and uses it to compute recency.
• data/last_coherence.json — a small JSON file the script writes on every run. Canonical timestamp source.

If neither file exists, the script returns a high hours_since_last_pulse (i.e. ancient) and the field reads low.

Output (stdout) — a single JSON object:

{
  "strength": 0.524,
  "label": "COHERENT",
  "components": {
    "recency": 0.995,
    "energy_24h": 0.065,
    "rhythm": 0.013,
    "chrono_utc": 0.083,
    "hours_since_last_pulse": 0.8
  },
  "sampled_at": "2026-06-08T23:11:35Z"
}

• strength — the field reading, [0, 1].
• label — bucket: DORMANT (< 0.20), STIRRING (< 0.50), COHERENT (< 0.80), RESONANT (≥ 0.80).
• components — the four weighted signals. Use them to debug why the field reads what it reads.
• sampled_at — the ISO timestamp of this run.

Side effect (with --fossil) — appends one line to memory/pulse_log.md:

## 2026-06-08T23:15:26Z | COHERENT 0.540 | recency=1.00 energy=0.08 rhythm=0.08 chrono=0.08 — field stabilized at 0.54

Components

The reading is a weighted sum:

All weights are inline in compute(). Tune by editing the script — there is no config file.

How to read the components

• recency ≈ 0 and everything else fine: you've been sampling, but not recently. Run --fossil.
• energy_24h ≈ 0: nothing in the workspace has been touched in 24h. The space is dormant by another name.
• rhythm ≈ 0 with recency ≈ 1: this is your first sample. You have no rhythm yet. Run again tomorrow.
• chrono_utc ≈ 0: it's the wrong time of day. (Less meaningful for non-human workspaces.)

Schema flexibility

The script reads data/last_coherence.json (its own canonical timestamp source) and memory/pulse_log.md (the fossil log). It does not read data/state.json directly. state.json is a long-form record for cross-agent reference; it is the script's own last_coherence.json that drives the field. If you want your agent's state.json to also carry a coherence reading, write a small bridge that copies the script's output into your state's medulla.last_coherence field after each run.

Anti-patterns

• Do not run the script in a loop and average the readings. The field is a snapshot, not a series. If you want a series, log each reading and look at the series.
• Do not set the field as an environment variable. It goes stale instantly. Re-sample.
• Do not edit last_coherence.json by hand to spoof a higher reading. The field is for the system, not for display.
• Do not use the field as a routing signal. A DORMANT reading is a fact, not a permission to skip work. The work happens regardless of the field; the field tells you how coherent the work is.

Customizing

Two paths in the script are hard-coded:

WORKSPACE = Path("/home/workspace/ghojualamanchu")
PULSE_LOG = WORKSPACE / "memory" / "pulse_log.md"
LAST_COHERENCE = WORKSPACE / "data" / "last_coherence.json"

Change WORKSPACE to your workspace root. Everything else is relative.

Origin

Built in the ghojualamanchu workspace on 2026-06-08, during a conversation about whether a self-modeling agent should record itself as a counter (crystal) or a coherence (plasmoid). The plasmoid won because the question "how alive is this right now" is more useful than the question "how long has it been alive."

The crystal version is preserved in subagents/medulla-heartbeat.md and is still runnable; the two are complementary, not replacements.

Files in this folder

• field-strength.py — the sampler.
• SKILL.md — the skills-index entry.
• plasmoid-field.md — the subagent spec.
• pulse_log_tail.md — the architecture note that explains why the plasmoid exists.
• last_coherence.json — an example of the file the script writes.
• index.html — this page.
• README.md — the same content as this page, in Markdown.