Night Market Architecture Contract

This skill records the design decisions that hold claude-night-market together, the invariants that enforcement code keeps true, and the weak points that are known and accepted. Read it before proposing a change that crosses a plugin boundary, touches a hook, adds a skill, or bumps a version. Every claim cites in-repo evidence: an ADR (Architecture Decision Record, in docs/adr/), a commit hash, or a checked-in enforcement file. Verify a citation before relying on it:

bash
git log --oneline -1 <hash>
rg -n "Status" docs/adr/<file>.md

Load-bearing decisions

1. Plugins are self-contained deployables

Each of the 23 plugins under plugins/ must install and run alone. There is no shared registry and no root-level shared library that plugins import at runtime (ADR-0001, Accepted). Plugins detect each other at runtime via filesystem checks and must degrade gracefully when a sibling is absent.

Cross-plugin DRY is an anti-pattern here, and that is settled by experiment, not taste. Commit 054e2679 consolidated 1164 lines of duplicated tasks_manager.py from attune, sanctum, and spec-kit into a shared root script. It broke plugin self-containment and was reverted in 29961cd2. The durable fix, d89a55c7, made the copies per-plugin and intentionally different. docs/dependency-audit.md records the per-plugin copies as the approved state. Do not re-propose the consolidation.

Practical test before you extract shared code: if a user installs only one plugin from the marketplace, does your change still work? If not, duplicate the code into each plugin instead.

2. Hooks run under host Python from a cache directory

Claude Code copies an installed plugin into a cache directory and runs its hooks under the host system Python, which can be as old as 3.9. The repo itself is Python 3.12 (root pyproject.toml, requires-python >= 3.12). Only hook scripts and their transitive import chains carry the 3.9 constraint. Five contract rules follow, each purchased with an outage:

| Rule | Why (evidence) | |------|----------------| | Hook code and every transitive import must be Python 3.9 compatible | datetime.UTC (a 3.11+ alias) broke the whole hook import chain repeatedly. ruff kept auto-reverting the fix until UP017 was globally ignored (pyproject.toml line 165) and an AST scan test held the line (plugins/leyline/tests/test_python39_compat.py) | | Read the hook payload as JSON on stdin, never from CLAUDE_TOOL_* env vars | Claude Code does not set those env vars, so env-reading hooks were silent no-ops for months (full record: night-market-failure-archaeology SB9). Canonical reader: read_hook_payload() in plugins/abstract/hooks/shared/hook_io.py | | No relative paths in hooks | The cache directory is not the repo checkout. conserve's session-start hook broke on a relative path and now inlines its JSON utilities (CHANGELOG) | | Hook entrypoints must import safely under a bare interpreter | An eager import yaml in gauntlet made every git commit emit ModuleNotFoundError. Guarded in 45dd77ef (#518), anthropic deferred in 9bfc0a7a | | Subprocess timeouts must sit below the budget registered in hooks.json | herald's LLM call once outlived its registered Stop-hook budget, so the harness killed the hook with no verdict at all (full record: night-market-failure-archaeology SB7). Guard test: plugins/herald/tests/unit/test_double_shot_latte.py |

CI enforcement: .github/workflows/python39-compat.yml runs two gates with uneven coverage. Gate 1 (ruff UP007, flags 3.10+ union syntax) covers 12 plugins' hooks/ dirs. Gate 2 (hook test suites inside a real Python 3.9 venv) covers only 7 plugins: abstract, conserve, egregore, imbue, leyline, memory-palace, sanctum. herald ships a Stop hook yet appears in neither gate.

3. One ecosystem version, fanned out to every manifest

.claude-plugin/marketplace.json is the version source of truth (1.9.15 as of 2026-07-02). Each plugin carries three manifests that must stay in sync with it and with each other:

• .claude-plugin/plugin.json (name, version, component arrays)
• .claude-plugin/metadata.json (version plus dependency hints)
• openpackage.yml (cross-framework manifest)

Plus pyproject.toml and any __init__.py carrying __version__. Never hand-edit versions across files. Use the bumper, which finds and rewrites all of them:

bash
uv run python plugins/sanctum/scripts/update_versions.py <version>

One trap: metadata.json dependencies (for example imbue declaring "abstract": ">=2.0.0") is a separate semver namespace for capability compatibility. It does not track the marketplace version and a 2.0.0 there does not mean marketplace 2.0.0 exists.

4. Skill discovery budget is finite and overflow is silent

Claude Code loads every installed skill's description into context at 2% of the context window, with a 16,000-character fallback (ADR-0004, Accepted, updated 2026-05-21). Descriptions that exceed the budget make skills invisible with no error anywhere. That is why:

• Each description is capped at 160 characters

(docs/skill-description-guide.md), enforced by the validate-description-budget pre-commit hook backed by plugins/abstract/scripts/validate_budget.py.

• The ecosystem-wide validator ceiling is 90,000 characters

(DEFAULT_BUDGET in plugins/abstract/scripts/validate_budget.py, overridable via SLASH_COMMAND_TOOL_CHAR_BUDGET). ADR-0004 and docs/skill-description-guide.md still cite a stale 60,000 figure; the script is the enforcer. Flag the ADR for an update through change control.

When adding a skill, spend the 160 characters on trigger phrases, not on restating the name.

5. Collective memory and trust are external services

Decisions, learnings, and audit syntheses are posted to GitHub Discussions, which act as agent collective memory across sessions (ADR-0007, Accepted). There is no gh discussion subcommand: all Discussions access goes through gh api graphql. Release trust is established by SLSA attestation (Supply-chain Levels for Software Artifacts) of trust-report.json on master pushes (.github/workflows/trust-attestation.yml). The original blockchain design (ERC-8004) was dropped for cost. ADR-0008 is marked Superseded 2026-03-15 and now points at GitHub Attestations. See night-market-collective-memory for the Discussions workflow.

6. Every skill has one of three roles

docs/skill-integration-guide.md defines the role taxonomy used when judging whether a skill is an orphan or a hub:

| Role | Inbound refs | Invoked directly | Example | |------|--------------|------------------|---------| | entrypoint | low (0-3) | yes | sanctum:do-issue | | library | high (4+) | rarely | imbue:proof-of-work | | hook-target | varies | no | imbue:vow-enforcement |

A skill with zero inbound Skill() references is only a problem if it also has no command path and no hook that loads it. Check the role before archiving anything.

Invariants

Each row names the enforcement that keeps the invariant true. If you weaken the enforcement, you own the failure mode in the third column.

| Invariant | Enforced by | What breaks if violated | |-----------|-------------|-------------------------| | Hook import chains are Python 3.9 safe | .github/workflows/python39-compat.yml (2 gates) plus AST scan test plugins/leyline/tests/test_python39_compat.py | Total hook outage: one 3.11-only import kills every hook that transitively loads the module | | No bare except: and errors propagate by default | ruff E ruleset (root pyproject.toml) plus CONSTITUTION.md rule 10 | Scanners silently drop files and report success on garbage input, and failures become invisible | | All manifests carry the same ecosystem version | plugins/sanctum/scripts/update_versions.py rewrites pyproject/plugin.json/metadata.json/openpackage.yml/__init__.py in one pass | Version drift across ~100 files, and marketplace.json stops being the source of truth | | book/src/reference/capabilities-reference.md matches plugin registrations | scripts/capabilities-sync-check.sh via make docs-sync-check and .github/workflows/capabilities-sync.yml | Published docs advertise components that do not exist, or hide ones that do | | No new dangling Skill(plugin:name) references | scripts/check_skill_graph_drift.py ratchet against scripts/skill_graph_baseline.json | A model tries to load the referenced skill and silently gets nothing | | Every SKILL.md has an ## Exit Criteria section | scripts/check_skill_exit_criteria_drift.py ratchet against scripts/skill_exit_criteria_baseline.json | Skills the model cannot tell when to stop executing (vague success criteria at scale) | | Hook subprocess timeout < registered hook budget | Guard test in plugins/herald/tests/unit/test_double_shot_latte.py asserts LLM_TIMEOUT_SECONDS fits inside the hooks.json timeout | Harness kills the hook mid-flight and no verdict is emitted at all | | Hook payloads are read stdin-first | plugins/abstract/hooks/shared/hook_io.py read_hook_payload() shared by hook scripts | Hooks become silent no-ops (this happened, and the only symptom was a starved learning digest) |

The two ratchet scripts share one mechanic: they fail a commit only when the violation count rises above the committed baseline, and they ask you to lower the baseline when the count drops. Never raise a baseline to get a commit through. That is routing around change control. One documented exception: a brand-new library skill legitimately starts uncalled, and scripts/check_skill_graph_drift.py (plus the _comment in scripts/skill_graph_baseline.json) instructs you to raise max_uncalled_libraries to record the 30-day consumer grace period that .claude/rules/shared-utility-consumer-rule.md grants. See night-market-change-control.

Known weak points

Stated plainly so nobody rediscovers them the hard way. These are open by decision or by neglect, not secrets.

1. Skill-discovery overflow is silent. If total description overhead

exceeds the context budget, skills vanish with no error (ADR-0004). The 160-char cap and validator ceiling are preventive guards. There is no runtime detection of overflow.

1. The quality-gate federation has one real orchestrator. The gate

skills (karpathy-principles, scope-guard, proof-of-work, justify, rigorous-reasoning, vow-enforcement) are designed to compose, but only egregore:quality-gate sequences the full pipeline today (docs/quality-gates.md, "Who currently orchestrates"). Every other consumer picks gates ad hoc.

1. docs/project-brief.md, docs/specification.md, and

docs/implementation-plan.md are overwritten each feature cycle. The current contents describe only the latest cycle (insight-palace bridge as of 2026-07-02). Past cycles survive only in git history. Do not cite these files as a permanent record.

1. Duplicate module names across plugins force per-plugin mypy.

Running mypy plugins/ from the root collides on duplicate module names (comment in .github/workflows/typecheck.yml). The same constraint makes root pytest exclude plugins/* (norecursedirs in root pyproject.toml, and root conftest.py documents the ImportPathMismatchError). Always run plugin tests and typechecks per plugin.

1. mdbook is unpinned in the deploy workflow.

.github/workflows/deploy-book.yml installs mdbook-version: 'latest', so an upstream mdbook release can break the book deploy with no repo change. Candidate fix: pin a version. Not done as of 2026-07-02.

ADR digest

All 17 records live in docs/adr/. Statuses read from the files on 2026-07-02.

| ADR | Title | Status | One-line takeaway | |-----|-------|--------|-------------------| | 0001 | Plugin Dependency Isolation | Accepted | No shared registry. Runtime filesystem detection with graceful degradation | | 0002 | Extract QuotaTracker to Leyline | Accepted | Quota tracking moved from conjure into leyline for reuse | | 0003 | Command Description Refactoring | Accepted | Two-part descriptions: short display line, rich identification text | | 0004 | Skill Description Budget Optimization | Accepted (updated 2026-05-21) | 160-char cap. Budget is 2% of context, 16k fallback. Its 60k validator ceiling is stale: the enforcing script uses 90k | | 0005 | Attune Plugin Discoverability Enhancement | Accepted (2026-02-05) | Superpowers-style trigger phrasing for attune components | | 0006 | Self-Adapting Skill Health | Accepted (2026-02-15) | Homeostatic monitoring detects degrading skills | | 0007 | GitHub Discussions as Agent Collective Memory | Accepted (2026-02-19) | Decisions and learnings posted to Discussions (GraphQL only) | | 0008 | Behavioral Contract Verification Framework | Superseded (2026-03-15) | ERC-8004 blockchain dropped for cost. GitHub Attestations (SLSA) instead | | 0009 | Sidecar Service Discovery via Port Files | Accepted | Sidecar daemons publish their ports through port files | | 0010 | Stacked Diff Workflows | Accepted | git --update-refs plus gh pr create --base as zero-dependency stacking | | 0011 | Shared Session-Capture Envelope | Accepted | One JSON envelope shape for friction and trace payloads, separate files | | 0012 | Confidence-Tagged Agent Claims | Superseded by 0017 | VERIFIED/INFERRED/ASSUMPTION tags: no enforcement built | | 0013 | Operationalizing Naur Theory-Building | Superseded by 0017 | Theory-building rituals: folded into 0017's lighter form | | 0014 | Pensive Review-Skill Consolidation | Accepted (sequencing only) | 9 review skills, 5 sharing a verdict scaffold. Consolidation sequenced, not done | | 0015 | Over-Built Orchestrator Skill Simplification | Accepted (data-collection phase) | Collect 30 days of usage data before simplifying over-built skills | | 0016 | Wire-or-Archive for Three Orphan Skills | Accepted (decisions recorded) | Orphans judged on demand signal, wiring cost, and reference value | | 0017 | Decisions on Confidence-Tagging and Theory-Building | Accepted (2026-06-18) | No enforcement mechanisms and voluntary use. Supersedes 0012 and 0013 |

When NOT to use

| You actually need | Use instead | |-------------------|-------------| | How a change is classified, gated, and reviewed | night-market-change-control | | The full story of a past incident or revert | night-market-failure-archaeology | | Commands to run tests, lint, release, publish | night-market-operations | | Every config file, default, and env var | night-market-config-catalog | | Plugin/skill/hook mechanics in the abstract | claude-code-plugin-reference | | Triage for a live failure | night-market-debugging-playbook |

Exit Criteria

• ] You can state why cross-plugin shared code is rejected, citing

ADR-0001 and commits 054e2679 and 29961cd2, and both commits resolve via git log --oneline -1 <hash>.

• ] Every enforcement file named in the Invariants table exists:

ls each path in the second column from the repo root with zero errors.

• ] The ADR digest row count matches

ls docs/adr/*.md | wc -l (17 as of 2026-07-02).

• ] For a proposed change, you can name which invariant row (if

any) it touches and which weak point (if any) it worsens, before writing code.

• ] The version printed by

rg -m1 '"version"' .claude-plugin/marketplace.json matches the version in every plugin's plugin.json you spot-check.

Provenance and maintenance

Compiled 2026-07-02 against repo v1.9.15 on branch discussions-fix-1.9.14. Skill/plugin counts drift: 198 SKILL.md files under plugins/ and 23 marketplace plugins at compile time.

Re-verify volatile facts:

bash
# ADR count and statuses
rg -m1 -n "Status" docs/adr/*.md

# Ecosystem version source of truth
rg -m1 '"version"' .claude-plugin/marketplace.json

# Discovery budget numbers (2%, 16k fallback; the ADR still says 60k)
rg -n "16,000|60,000" docs/adr/0004-skill-description-budget-optimization.md

# Enforced validator ceiling (90,000 as of 2026-07-03)
rg -n "DEFAULT_BUDGET" plugins/abstract/scripts/validate_budget.py

# Who orchestrates the gate federation today
rg -n "orchestrat" docs/quality-gates.md

# mdbook still unpinned?
rg -n "mdbook-version" .github/workflows/deploy-book.yml

# Ratchet baselines still present
ls scripts/skill_graph_baseline.json scripts/skill_exit_criteria_baseline.json

# Plugin and skill counts
python3 -c "import json;print(len(json.load(open('.claude-plugin/marketplace.json'))['plugins']))"
find plugins -name SKILL.md | wc -l