feat: rework Priors as a Claude Code plugin (memory always on, writing gated by mode)

[claudialnathan]

Summary

Reworks Priors from CLI-first into a Claude Code plugin-first product, while keeping the safety substrate (MCP server, deterministic brief, quote-or-refuse, append-only audit, idempotency, project-as-subject) intact.

Replaces the auto-closed PR #13 (closed by GitHub when the branch was force-pushed after a git filter-repo history cleanup — see "History rewrite" section below).

Users used to type priors stage --source-content @… --candidates @… and manage a staged/ queue by id. With this PR, day-to-day flow moves into Claude Code:

/plugin marketplace add https://github.com/claudialnathan/priors
/plugin install priors@priors

Then /priors:recall, /priors:log, /priors:rules, /priors:why, /priors:impact, /priors:reflect, etc.

What's new

• Plugin scaffold at repo root using the modern Claude Code layout per https://code.claude.com/docs/en/plugins:
  • .claude-plugin/plugin.json + .claude-plugin/marketplace.json (single-plugin marketplace catalog)
  • skills/<name>/SKILL.md (10 slash commands, auto-namespaced as /priors:<name>)
  • agents/priors-steward.md
  • hooks/hooks.json + bounded shell scripts
  • .mcp.json
• Two modes (auto | manual) in .priors/config.json. Memory use is always on; memory writing toggles between modes. Auto mode is bounded by a significance gate.
• New entry kind rule. User-authored rules write directly via priors rule add (or /priors:rule-add — the user typed the claim, no quote-or-refuse needed). Agent-inferred rules still pass through the review queue.
• Readable IDs (D-001, F-004, R-002) for human-facing flows. Canonical slug ids preserved in metadata, exports, and --json output.
• New surfaces: /priors:why, /priors:impact, /priors:reflect, /priors:log, /priors:rules, /priors:rule-add, /priors:status. Pushback formatter, natural-language log-intent detector, and significance gate live as pure modules under src/intent/ and src/session/.
• Cursor compatibility: .cursor/rules/priors.mdc (always-apply rule) + .cursor/mcp.json. Legacy single-file .cursorrules removed in favour of the modern .cursor/rules/*.mdc directory format.
• Lifecycle hooks (SessionStart, UserPromptSubmit, PreCompact, Stop) — all bounded, none call an LLM.

What's preserved

• MCP server and full tool surface.
• Deterministic priors://brief (no LLM in the assembler — same store in, same bytes out).
• Quote-or-refuse on agent-proposed candidates (substring + Dice-coefficient grounding floor).
• Append-only audit logs.
• Idempotency keys on every MCP write tool.
• The .priors/ store layout. The new entries/rules/ directory is additive.
• Seven-task regression suite. Every existing CLI subcommand.

Backward compatibility: existing entries parse unchanged (all new frontmatter fields are optional). Existing CLI users keep their full surface.

History rewrite

git filter-repo was used on this branch to scrub personal Claude Code dev-tool installs (.agents/, .claude/skills/, skills-lock.json) and the legacy .cursorrules from all of main's history. Pre-rewrite commit SHAs are no longer reachable. Anyone with an older clone needs to re-clone or git fetch && git reset --hard origin/main.

The published priors@1.0.0-rc.0 and priors@1.0.0-rc.1 npm tarballs were verified clean before the rewrite (the package.json files[] allowlist had already excluded those paths from the published packages), so nothing on npm needed retraction.

Personal vs shipped — gitignore convention

Concern	Personal (gitignored)	Shipped (tracked)
Project memory	CLAUDE.local.md	CLAUDE.md
Subagents	.claude/agents/<name>.md	agents/priors-steward.md
Skills	.claude/skills/<name>/SKILL.md	skills/<name>/SKILL.md
Settings	.claude/settings.local.json	.claude-plugin/plugin.json
Cursor rules	.cursor/rules.local/<name>.mdc	.cursor/rules/priors.mdc

Rule of thumb: leading dot (.claude/...) = personal; plural noun without leading dot (agents/, skills/) = the plugin's published asset.

Test plan

• npm test — 232/232 passing (was 186 before this PR)
• CLI smoke test in /tmp: init, mode auto/manual, rule add, log, rules, status, resolve, recall, hook session-start/user-prompt, impact, reflect, why — all working
• Verified git filter-repo history rewrite produces a clean history across main, feat/plugin-rework, and legacy/v0.3.0
• Verified published npm tarballs (1.0.0-rc.0, 1.0.0-rc.1) are clean — no personal artifacts ever shipped
• Plugin install via /plugin marketplace add — verify hooks fire and slash commands appear in a fresh Claude Code session
• Verify .priors/ lands in the user project (not the plugin dir) when installed

After merge

1. Bump package.json version to 1.1.0-rc.1 (additive, still rc).
2. Tag v1.1.0-rc.1.
3. npm publish --tag next.

🤖 Generated with Claude Code