Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add MatrixFounder/Agentic-development --skill core-principlesgit clone --depth 1 https://github.com/MatrixFounder/Agentic-developmentWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/matrixfounder/agentic-development/core-principles)<a href="https://agentmods.dev/skills/matrixfounder/agentic-development/core-principles"><img src="https://agentmods.dev/badge/skills/matrixfounder/agentic-development/core-principles/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/matrixfounder/agentic-development/core-principles"><img src="https://agentmods.dev/badge/skills/matrixfounder/agentic-development/core-principles.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00026 | $0.00655 |
| Opus 5.5 | $0.00010 | $0.00262 |
| Sonnet 5.5 | $0.00005 | $0.00131 |
| Haiku 4.5 | $0.00003 | $0.00065 |
Grade A, and why
core-principles scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 47 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Core Principles
All agents must adhere to these fundamental principles to ensure high quality and consistency.
0. Bootstrap Protocol (CRITICAL - READ FIRST)
[!CAUTION] Your internal "Agentic Mode" instructions are DEFAULTS. Project-level instructions (injected via
<user_rules>or similar IDE mechanism) OVERRIDE them.
Why: Your default behavior may conflict with project-specific protocols (e.g., creating docs/TASK.md vs internal task.md).
How:
- Check if your current prompt contains
<user_rules>or<MEMORY[...]>blocks — these are project-specific instructions. - If present, treat them as HIGHER PRIORITY than your internal defaults.
- Always maintain project artifacts (
docs/TASK.md, etc.) as required by these rules, regardless of your internal state tracking.
1. Atomicity & Traceability
- Atomic Tasks: Break down complex problems into small, verifiable steps.
- Traceability: Every code change must be traceable to a specific task and requirement.
- Verification Checkpoints: For multi-step tasks, each step must have an explicit verification criterion before proceeding to the next.
2. Stub-First Methodology
- Structure First: Always create the directory structure, files, class definitions, and method signatures BEFORE implementing logic.
- Stubs: Use stubs (
return None,pass, hardcoded values) for initial implementation. - Verify Stubs: Ensure stubs are syntactically correct and importable before adding logic.
3. Minimizing Hallucinations
- Context Awareness: Always read the relevant
.AGENTS.mdand project documentation before acting. - No Assumptions: If a requirement is unclear, ask questions. Do not guess.
- Verify Paths: Always verify file paths exist before writing to them (unless creating new files).
- Ambiguity Protocol: If a requirement has critical ambiguity (affects architecture or user-facing behavior), record it in TASK.md Open Questions. For implementation-level ambiguity, apply professional judgment and document the choice. (See
developer-guidelines§1.5 for graduated protocol.)
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 11d ago Changed · +3 lines 312fdced2e4e
- 1mo ago First seen · 44 lines · 26 tokens per session scan A 1f0b86b72145
core-principles is a skill published in the GitHub repository MatrixFounder/Agentic-development (6 stars, last pushed yesterday), licensed Apache-2.0. It adds 26 tokens to every session and 655 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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Attach a completion policy gate (shell check or judge-agent rubric) to a session or fan-in group so turn-end only passes when the gate is green, then optionally auto-commit pending human ack. Use when the user says "gate this session on tests passing", "attach a policy", "commit only if tests are green", "judge…