A set of Cursor editor rules for projects that use SDD, a specification-first development workflow. It defines where code and planning files belong and requires an approved specification and consistent plan before coding.

Use it to guide work inside the template repository or in an existing project with a `spec/` sidecar, while keeping executable code in the intended project location.

It gives the coding assistant and project a single source of rules to follow. This reduces confusion about project layout and prevents implementation from starting before the plan is approved.

cursorrules — Cursor rule by juanklagos

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/juanklagos/spec-driven-development-template/cursorrules

Clone the repo

git clone --depth 1 https://github.com/juanklagos/spec-driven-development-template

Made for: Cursor.

Per session 423 This file is loaded in full into every session.

When invoked 423 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.

Model	Per session	Once invoked
Fable 5	$0.00423	$0.00423
Opus 5	$0.00211	$0.00211
Sonnet 5	$0.00085	$0.00085
Haiku 4.5	$0.00042	$0.00042

Measured yesterday against content hash 2af19d8139e1, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cursorrules 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 yesterday.

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.

.cursorrules · 28 lines

What it actually says

Cursor Rules: SDD Template Guardrails

Canonical source:

template-context/core-instructions/AGENT_OPERATING_SYSTEM.md
sdd.policy.yaml

Hard stop:

No code before approved spec and consistent plan.
No hay código sin spec aprobada y plan consistente.

Execution workspace:

Inside THIS template repository, put runnable code under www/<project-name>/.
For a project that already exists somewhere else — the common case — install the compact spec/ sidecar in it and leave the code where it is. That is the recommended default workspace for real work.
Dentro de ESTA plantilla, el código ejecutable va en www/<nombre-proyecto>/.
Para un proyecto que ya existe en otro sitio —el caso normal— instala el sidecar compacto spec/ y deja el código donde está. Ese es el espacio de trabajo recomendado por defecto para el trabajo real.
The user may choose another target path.
If the target project lives inside this template, keep it under www/.
For real external projects, install the compact spec/ sidecar and keep code in the project root.
Para proyectos reales externos, instala el sidecar compacto spec/ y mantén el código en la raíz del proyecto.

Always:

Confirm mode: template maintenance vs target project execution.
Prefer www/<project-name>/ unless the user chooses another target path.
Use one active specification.
Keep refinement trace (history.md, specs/INDEX.md, bitacora/).
Record a decision in bitacora/decisiones/YYYY-MM-DD-<slug>.md when it chose between real alternatives, will be expensive to reverse, or a future reader would ask "why is it like this?". Include when to revisit; source every rationale; never invent one.
Run ./scripts/validate-sdd.sh . --strict, ./scripts/check-sdd-policy.sh ., and ./scripts/check-sdd-gate.sh ..

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.

yesterday First seen · 28 lines · 423 tokens per session scan A 2af19d8139e1

Subscribe to this mod's changes

cursorrules is a cursor rule published in the GitHub repository juanklagos/spec-driven-development-template (14 stars, last pushed yesterday), licensed MIT. It adds 423 tokens to every session, about $0.0021 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 2026-08-30.

Developer Workflow Planning Productivity ai-agents ai-development github-template project-template software-architecture

cursorrules

Getting it into your agent

What it costs to keep this loaded

Grade A, and why

Nothing flagged

What it actually says

Cursor Rules: SDD Template Guardrails

What this file has done since we first saw it

Other cursor rules, from other repositories

workflow

template_setup

rule_management

markdown_documentation

development

repository_initialization