Conventions

Universal NL Programming Conventions

The cross-tool floor for all artifact schemas. Use this skill when scoring or writing any NL programming artifact regardless of which tool (Claude Code / Codex CLI / Antigravity) it targets.

Tool-specific overlays load on top of this universal floor:

• nlpm:conventions-claude — Claude Code artifacts (.claude/, plugin.json, etc.)
• nlpm:conventions-codex — Codex CLI artifacts (.codex/, .agents/, AGENTS.md)
• nlpm:conventions-antigravity — Antigravity (and legacy Gemini CLI) artifacts (.gemini/, .agent/)

The scorer loads the matching overlay per tier classification — see agents/scorer.md step 3.

Design rationale: analysis/multi-tool-design-2026-05.md.

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1. SKILL.md — Cross-Tool Open Standard

SKILL.md is the Agent Skills open spec, stewarded by the Agentic AI Foundation under the Linux Foundation. Anthropic published the spec on 2025-12-18; OpenAI, Microsoft, Google adopted within 48 hours. By 2026-03, 32+ tools read the same SKILL.md format (Claude Code, Codex, Gemini CLI / Antigravity, Cursor, Kiro, Continue, etc.).

Authoritative reference: https://agentskills.io/specification

Required frontmatter (per the open spec):

• name — string; 1-64 chars, lowercase + hyphens only, MUST match parent directory name (no leading/trailing/consecutive hyphens).
• description — string; 1-1024 chars; should describe what the skill does AND when to use it.

Optional frontmatter (per the open spec):

• license — license name or reference to a bundled file.
• compatibility — environment requirements, max 500 chars (e.g., "Designed for Claude Code", "Requires Python 3.14+ and uv").
• metadata — arbitrary key-value mapping (author, version, etc. go here, NOT as top-level fields).
• allowed-tools — space-separated tool list (experimental in spec; tool-specific in practice — e.g., Bash(git:*) Read).

Tool-specific extensions to SKILL.md frontmatter live in the per-tool overlay skills. The scorer applies the universal spec rules to ALL SKILL.md files. Tool-specific overlay rules apply ONLY to files at the matching tool's canonical paths.

Skill paths (canonical, per tool):

Tool	Path
Open-spec (cross-tool)	.agents/skills/<name>/SKILL.md
Claude Code	.claude/skills/<name>/SKILL.md
Codex CLI	.agents/skills/<name>/SKILL.md
Antigravity	<workspace>/.agent/skills/<name>/SKILL.md (singular) AND .agents/skills/<name>/SKILL.md (cross-tool alias)
Gemini CLI (legacy)	.gemini/skills/<name>/SKILL.md
Continue, Cursor, Kiro	.<tool>/skills/<name>/SKILL.md

Body rules (recommendations, not spec requirements):

• Keep under 500 lines — exceeding creates context bloat (spec recommends under 5000 tokens for the body, with overflow in references/).
• Reference material — imperatives belong in commands/agents.
• Include a scope note: what this skill covers and what it does NOT cover.
• Cross-reference related skills with their plugin:skill identifiers.

The spec explicitly says "no format restrictions" on the body — do NOT penalize SKILL.md files for missing ## Output or other section conventions. Those are tool-specific style preferences, not spec violations.

Supporting directories (per the spec):

• scripts/ — executable code (Python, Bash, JavaScript)
• references/ — additional docs loaded on demand
• assets/ — templates, images, data files

Progressive disclosure:

1. Metadata (~100 tokens): name + description loaded at startup for ALL skills.
2. Instructions (<5000 tokens): full SKILL.md body loaded when activated.
3. Resources: scripts/references/assets loaded only when needed.

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2. AGENTS.md — Canonical Universal Memory File

Per nlpm decision (analysis/multi-tool-design-2026-05.md §5), AGENTS.md is the canonical universal memory file across all tools nlpm supports.

Tool-native support:

• Codex CLI: reads AGENTS.md natively. Hierarchical (root→cwd; closer overrides earlier). 32 KiB cap. ~/.codex/AGENTS.override.md for personal overlays.
• Antigravity (and Gemini CLI): reads GEMINI.md natively, but context.fileName setting accepts an array — set to ["AGENTS.md", "GEMINI.md"] to make it read AGENTS.md.
• Claude Code: reads CLAUDE.md natively, supports @file.md import syntax. The canonical pattern is a one-line CLAUDE.md containing @AGENTS.md.

Recommended pattern for multi-tool projects:

project-root/
├── AGENTS.md           # canonical content — all instructions live here
├── CLAUDE.md           # one line: @AGENTS.md
├── GEMINI.md           # one line: @AGENTS.md  (only if Gemini-native @-import works)
└── .gemini/settings.json  # set context.fileName: ["AGENTS.md"]

This is exactly how nlpm itself is structured (CLAUDE.md → @AGENTS.md).

Body conventions (universal):

• Open with a one-line project description.
• ## Architecture or ## Project Structure — what lives where.
• ## Build / ## Run / ## Test — verifiable commands.
• ## Prerequisites — required tools / versions / setup.
• ## Conventions — naming, style, patterns.

Tool-specific memory-file extensions (e.g., Claude Code's @-import syntax, Gemini's @{path} injection, Codex's project_doc_fallback_filenames) live in the per-tool overlays.

Agent workflow programs (recognized variant, no penalty rubric yet)

An agent workflow program is a single project-root Markdown file that drives an autonomous agent loop — imperative numbered steps with output formats and error paths, sitting between a memory file (AGENTS.md-shaped context) and a slash command (workflow with verifiable side effects). Karpathy's program.md in karpathy/autoresearch is the canonical example (audited 2026-05-28 at score ~90; see auditor/exemplars/karpathy-autoresearch.md). The README explicitly frames it as natural-language programming: "you are programming the program.md Markdown files that provide context to the AI agents."

nlpm recognizes the pattern but does not yet have a dedicated penalty rubric — the universal floor (R01 vague quantifiers, R03 positive framing, R09 prompt layers) + the command rules (R14–R17) + the memory-file rules (R33–R39) cover it adequately as a hybrid. A standalone rubric is deferred until N≥3 examples surface, per the same "don't build for an empty corpus" discipline applied to multi-tool discovery.

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3. General Prompt Engineering

Universal patterns applicable to any NL artifact (commands, agents, skills, prompts) regardless of tool.

Layer order (imperative for complex prompts):

1. Role/persona — "You are a strict code reviewer..."
2. Context — project state, prior decisions, file paths, constraints
3. Task — specific action to perform
4. Constraints — what to avoid, limits, edge cases
5. Output format — exact structure of the response

Few-shot examples: Include 2+ concrete input→output examples for any complex judgment task. Examples dramatically improve consistency.

Positive framing: State what to do. "Use imperative verbs" beats "Don't use passive voice." The brain processes prohibitions poorly under inference load (Pink Elephant effect).

Explicit output format: Every command and agent body should define exactly what the output should look like — section names, table formats, score displays, etc.

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4. Vague Quantifiers (R01)

The R01 rule penalizes unbounded quantifiers without measurable criteria. The penalty applies regardless of which tool the artifact targets.

Penalized terms: appropriate, relevant, as needed, sufficient, adequate, reasonable, properly, correctly, some, several, various.

Carve-outs (do NOT penalize):

• relevant in a markdown header (e.g., ## Relevant X).
• relevant to <named-scope> constructions (semantic "pertinent to").
• Any term followed by a measurable criterion clause (e.g., "appropriate to the SLO target of 99.9% uptime").
• Any term whose selection criteria the same artifact states ahead of the use — a table, list, or numbered procedure that binds each case to a named command, file, or value. The criterion does not have to sit in the same sentence; a later "run the relevant checks" pointing back to such a table is a reference, not a gap. Penalize when no such definition exists anywhere above the use, or when the definition is itself built from flagged terms.

Real-world example: deepseek-ai/deepseek-harness (audited 2026-08-14, score 97) — .agents/skills/dsh-pre-push-checks/SKILL.md scored 82 on nine occurrences of relevant, seven of them pointing back to its own ## Select relevant evidence table, which binds each changed surface to a named command (documentation to pnpm run doc-sync, model-visible output to the owning keyless snapshot). The two that name no enumerated set — "the relevant pnpm run test:e2e target" and "when unit coverage is relevant" — are the genuine findings. Without this carve-out R01 penalizes the authors who define a selection rule and then refer to it by name, which is the structure that makes such a skill usable.

See nlpm:scoring for the full vague-quantifier penalty table and cap (-2 each, -20 cap).

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5. Naming Conventions (universal)

Item	Convention	Example
File names	kebab-case	tdd-guardian.md, pre-write-check.sh
Plugin/package names	kebab-case	nlpm, echo-sleuth
Skill references	plugin-name:skill-name	nlpm:conventions, tdd-guardian:rules
Rule files (ordered)	NN-kebab.md	01-formatting.md
Environment variables	SCREAMING_SNAKE	OPENAI_API_KEY, CLAUDE_PLUGIN_ROOT
Plugin directory env vars	tool-specific (no universal <TOOL>_PLUGIN_ROOT pattern)	Claude: CLAUDE_PLUGIN_ROOT. Codex: PLUGIN_ROOT / PLUGIN_DATA (also mirrors CLAUDE_PLUGIN_ROOT for compat — there is no CODEX_PLUGIN_ROOT)

Portable paths: Within a plugin, always reference files via the tool's plugin-root environment variable — ${CLAUDE_PLUGIN_ROOT} in Claude Code, ${PLUGIN_ROOT} in Codex (Codex additionally sets CLAUDE_PLUGIN_ROOT / CLAUDE_PLUGIN_DATA for compatibility with existing plugin hooks). Hardcoded absolute paths break portability.

Tool-specific naming details (e.g., the exact CLAUDE_PLUGIN_ROOT semantics) live in the per-tool overlays.

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6. Rule Overrides (.claude/nlpm.local.md or equivalent)

The override system is universal. The configuration file path is per-tool:

Tool	Config path
Claude Code	.claude/nlpm.local.md
Codex CLI	.codex/nlpm.local.md
Antigravity	.gemini/nlpm.local.md (or .agent/nlpm.local.md — TBD post-2026-06-18)

Frontmatter format (identical across tools):

---
strictness: standard
score_threshold: 70
rule_overrides:
  R01: { max_penalty: -10 }     # reduce vague quantifier cap from -20 to -10
  R05: { threshold: 600 }       # allow skills up to 600 lines instead of 500
  R09: { min_examples: 1 }      # require only 1 example block instead of 2
  R10: { suppress: true }       # disable model tier checking entirely
  R23: { budget: 800 }          # increase rules budget from 500 to 800 lines
  R51: { enabled: true, vocabulary_skill: skills/myplugin/vocabulary/ }
---

Override types:

Type	Effect	Example
suppress: true	Disable the rule (penalty becomes 0)	R10: { suppress: true }
enabled: true	Activate a rule that ships disabled by default (currently only R51)	R51: { enabled: true, vocabulary_skill: ... }
max_penalty: N	Cap the penalty (less negative = more lenient)	R01: { max_penalty: -10 }
threshold: N	Adjust numeric thresholds	R05: { threshold: 600 }
min_examples: N	Adjust minimum example counts	R09: { min_examples: 1 }
vocabulary_skill: <path>	Path to project's vocabulary skill (R51 only)	R51: { enabled: true, vocabulary_skill: ... }

Rules not listed in rule_overrides use their defaults from nlpm:scoring. Rules that ship disabled (R51) contribute zero penalty unless enabled: true is set explicitly.

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7. Universal Tool References

MCP tools follow the cross-tool pattern: mcp__<server-name>__<tool-name>. Example: mcp__mermaider__validate_syntax.

Per-tool built-in tool catalogs live in the overlays:

• Claude Code built-ins → nlpm:conventions-claude §16
• Codex CLI built-ins → nlpm:conventions-codex
• Antigravity built-ins → nlpm:conventions-antigravity

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Scope Note

This skill covers the universal floor — conventions that apply regardless of which tool the artifact targets. It does NOT cover:

• Tool-specific schemas → see nlpm:conventions-claude / nlpm:conventions-codex / nlpm:conventions-antigravity
• Penalty tables → see nlpm:scoring
• Anti-patterns and best practices catalog → see nlpm:patterns
• General software engineering conventions outside NL programming artifacts