Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/kok-o/contextos-agentsnpx agentmods add rules/kok-o/contextos-agents/00-project-rulesWrote 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/rules/kok-o/contextos-agents/00-project-rules)<a href="https://agentmods.dev/rules/kok-o/contextos-agents/00-project-rules"><img src="https://agentmods.dev/badge/rules/kok-o/contextos-agents/00-project-rules/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/rules/kok-o/contextos-agents/00-project-rules"><img src="https://agentmods.dev/badge/rules/kok-o/contextos-agents/00-project-rules.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 | $0.00763 | $0.00763 |
| Opus 5.5 | $0.00305 | $0.00305 |
| Sonnet 5.5 | $0.00153 | $0.00153 |
| Haiku 4.5 | $0.00076 | $0.00076 |
Grade A, and why
00-project-rules 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 today.
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 — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.
ContextOS — Project Operating System Rules
ContextOS project instructions
Use the current task to select relevant instructions. Preserve the user's scope, existing authorization, and unrelated local changes.
Context routing
Read skill descriptions first. Load only relevant entrypoints, and read their examples or references only when those details are needed.
For explicit selection and explanation, run:
node .agents/ctx.js resolve "task description" --files src/example.ts --json
The resolver estimates skill body tokens. Client instructions, tool output, and chat history consume additional context. A soft budget can overflow for required instructions; examine warnings. Never truncate safety guidance to fit a limit.
Built-in skills
| Skill | Use when |
|---|---|
| engineering-workflow | Scope, implement, verify, or review work proportionally |
| ponytail-mindset | Choose a minimal implementation during substantive Build |
| security | Auth, sensitive data, user input, external integrations |
| context-os | Compiler, profiles, policy, adapters, context governance |
| context-manager | Compatibility alias for context-os |
| gstack-roles | Workflow alias; optional specialist perspectives |
| gemini-precision | Gemini execution guidance when that model is in use |
Canonical sources live in .agents/core/skills/; project overrides live in
.agents/project/skills/. Native projections live in .agents/skills/.
Resolve links relative to the loaded skill directory. Catalog skills are
installed on demand; do not assume an uninstalled skill is available.
Proportional workflow
For substantial or ambiguous features, establish desired behavior, acceptance criteria, and a concrete plan. Then implement, verify, review, and report. An explicit implementation request authorizes ordinary reversible work; carry that authorization forward. Ask for missing decisions that materially affect scope, safety, or external actions. Routine maintenance, diagnostics, documentation edits, and direct questions can proceed without a full ceremony.
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.
- today First seen · 87 lines · 763 tokens per session scan A 3a468f6092f7
00-project-rules is a cursor rule published in the GitHub repository kok-o/contextos-agents (10 stars, last pushed today), licensed Apache-2.0. It adds 763 tokens to every session, about $0.0031 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 2026-10-25.
Other cursor rules, from other repositories
vibeflow
Vibeflow spec-driven development methodology — guardrails, pipeline, and project knowledge system.
alembic-migrations
To add a non-nullable column and set a specific value for all existing rows without a persistent server default.
read-xlsx
Reading, writing, diffing, and repairing spreadsheets (.xlsx) for AI agents via the xfa MCP server.
shell-scripts
Shell Scripts.
mise
Mise.
cursorrules
═══════════════════════════════════════════════════════════ SPEC DRIVEN DEVELOPMENT — PROJECT CONSTITUTION Project: Freelance Time Tracker Version: v1.0.