Five loop primitives ship in your harness. Retenta is the sixth.

Loop engineering means designing loops that prompt agents — scheduled, unattended, iterating. Five of the six primitives now ship inside Claude Code and Codex. The sixth — memory — is still a markdown file. A capsule is that memory, productized: writable, semantic, ordered, and neutral across every harness.

The agent forgets. The Capsule doesn't.

The six loop primitives

Why a capsule beats the markdown file

Markdown is honest — deterministic, ordered, diffable, legible at a glance. A capsule keeps those and adds what a file can't.

The loop, in four tools

The retenta-memory skill teaches an agent to use them in order — recall at the start, log_progress at each milestone, remember for findings, cite sources — so it triggers automatically on loop and scheduled tasks.

Install for your harness

Copy your capsule's MCP URL and a named access key from its Connect box (create a key per harness under “Keys for loops & automations” — a Claude Code loop and a Codex loop each hold their own, independently revocable).

export RETENTA_MCP_URL="https://mcp.retenta.ai/c/<slug>/mcp"   # from the Connect box
export RETENTA_API_KEY="rk_live_…"                               # a named owner key

/plugin marketplace add thecrownjoel/retenta
/plugin install retenta-memory@retenta

export RETENTA_KEY="rk_live_…"                                   # a named owner key

codex mcp add retenta \
  --url https://mcp.retenta.ai/c/<slug>/mcp \
  --bearer-token-env-var RETENTA_KEY

mkdir -p ~/.agents/skills/retenta-memory
# save the retenta-memory SKILL.md there, then use  $retenta-memory

A nightly triage loop (any harness or cron)

The same tools over plain REST — recall the spine, do the work, log each step, remember the finding.

BASE="https://mcp.retenta.ai/c/<slug>"; KEY="rk_live_…"; RUN="$(date +%Y%m%d)"
auth(){ curl -s -H "Authorization: Bearer $KEY" -H "content-type: application/json" "$@"; }

# 1. load the whole spine at the start of the run
auth "$BASE/recall" -d '{"query":"nightly triage: what is open?"}'

# 2. …do the work…

# 3. record each milestone (idempotencyKey makes an at-least-once retry a safe no-op)
auth "$BASE/log_progress" -d '{"step":"triaged CI","status":"done","runId":"'$RUN'","idempotencyKey":"'$RUN'-triage"}'
auth "$BASE/log_progress" -d '{"step":"flaky test in the auth suite","status":"next","runId":"'$RUN'"}'

# 4. remember the synthesized finding (topic = one current note, last-write-wins)
auth "$BASE/remember" -d '{"text":"CI green; 1 flaky test remains","topic":"ci-status","runId":"'$RUN'"}'

Want proof it survives a kill? scripts/loop-demo.mjs runs three cycles as separate processes and shows cycle 3 recalling cycles 1–2.