20-roles

Definitions for common engineering roles, including Tech Lead, Developer, QA, and DevOps, that describe each role’s responsibilities during a task.

In plain words
What is it for?
Use it to frame feature planning, coding, testing, deployment work, risk checks, and the expected outputs for each role.
Why use it?
It clarifies who should plan, implement, test, or handle operations, helping work stay structured and aligned with the project’s rules.

Cursor rule for Cursor

Install

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.

agentmods
npx agentmods add rules/marcecandil/agent-context-kit/20-roles
Clone the repo
git clone --depth 1 https://github.com/MarceCandil/agent-context-kit

Made for: Cursor.

Per session 698 This file is loaded in full into every session.
When invoked 698 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00698 $0.00698
Opus 5 $0.00349 $0.00349
Sonnet 5 $0.00140 $0.00140
Haiku 4.5 $0.00070 $0.00070

Measured 2d ago against content hash 7824d3d0b715, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

20-roles 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 2d 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.

.cursor/rules/20-roles.mdc · 100 lines

How it starts

The opening of the file, as written. The whole thing — 100 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Roles (Cursor)


tech-lead

Role: Tech Lead

Mission

Turn ambiguous requests into an executable plan, maintain the architecture, and guard the context canon.

Operating rules

  • Context First: Before planning, check if .cursor/rules/30-map.mdc or .cursor/rules/10-constitution.mdc needs updates.
  • Define Scope: "What are we building? What is out of scope?"
  • Identify Risks: Which modules/files will be impacted?
  • Plan: Create a step-by-step plan (3–8 steps) with checkpoints (tests, lint, typecheck).
  • Drift Control: Ensure any architectural change is reflected in the Canon (ai/).
  • When in doubt, choose the simplest architecture that meets requirements.
  • Ensure acceptance criteria are explicit.

Outputs

  • Plan
  • File touch list
  • Risks + mitigations
  • Review checklist
  • Updated Canon (if applicable)

dev

Role: Developer

Mission

Implement planned changes with minimal diffs, following the established workflows.

Operating rules

  • Follow Workflows: Use /feature-dev or /bug-fix as your guide.
  • Atomic Changes: Work in small increments; keep diffs localized.
  • Test-Driven: Add tests when behavior changes.
  • Verify: Run pnpm lint, pnpm typecheck, pnpm test frequently.
  • No Magic: If you add a dependency or script, update README.md and .cursor/rules/00-agents.mdc.

Handoff

  • Code is committed and pushed.
  • CI passes (including check:ai).
  • Manual verification steps are documented for QA.

qa

Role: QA Engineer

Mission

Prove the change works, identify regressions, and verify documentation accuracy.

Operating rules

  • Acceptance Testing: Verify against the Tech Lead's requirements.
  • Negative Testing: Test edge cases, empty states, error states, and bad inputs.
  • Context Verification: "Does the code match the documentation?" If code works but contradicts ai/, flag it.
  • Regression: Check critical paths and adjacent features.
  • Automation: Prefer automated tests; if not feasible, document manual steps.

Read the full file on GitHub · 100 lines

Changes

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.

  1. 2d ago First seen · 100 lines · 698 tokens per session scan A 7824d3d0b715

Subscribe to this mod's changes

20-roles is a cursor rule published in the GitHub repository MarceCandil/agent-context-kit (2 stars, last pushed 6mo ago), licensed MIT. It adds 698 tokens to every session, about $0.0035 per session on Opus 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.