Vibecode LnkFlow

You are building a lean indie version of LnkFlow.

Create the following project files first, then implement the application by following them. Keep the files updated as decisions change. Do not collapse this into a single README or prompt.

===== README.md =====
# LnkFlow indie build

## Goal

Build the smallest trustworthy replacement for the core LnkFlow workflow for one developer or a tiny team.

## Scope

Resolve a slug to a destination at the edge, log the click, inject UTMs, pass ad click ids through untouched, and 302.

## Quick start

1. Install the documented dependencies.
2. Copy `.env.example` to `.env`.
3. Run the development command chosen during implementation.
4. Complete the acceptance checks in `BUILD_PLAN.md`.

## Honest limits

This build deliberately does not replace:
- Purchase events delivered back to Meta CAPI with stable event_id deduplication against the browser pixel
- Google offline conversion import keyed on gclid, gbraid, or wbraid
- click to lead to sale attribution that survives a multi-day gap, with refund reversal
- TLS on a customer's branded domain (Cloudflare for SaaS and 90-day DCV renewals, not one DNS record)
- per-creator performance and commission reporting

If those capabilities are essential, use Dub instead of pretending the gap is solved.

===== AGENTS.md =====
# Agent instructions

- Optimize for a working, understandable weekend build.
- Prefer the fewest moving parts that satisfy the brief.
- Do not invent cryptography, security guarantees, APIs, or compliance claims.
- Keep secrets out of source control and logs.
- Add focused tests for destructive, security-sensitive, and data-loss paths.
- Run the project checks before declaring the build complete.
- Record any deliberate shortcut in the README under "Tradeoffs".

===== BUILD_PLAN.md =====
# Build plan

## Original build brief

Build me a branded link shortener with click tracking to replace LnkFlow. Requirements:

- Cloudflare Workers via wrangler: KV for the slug lookup, D1 for the click
  log. Free tier, nothing to babysit.
- A worker on lnk.mydomain.com/{slug} reads KV, writes the click to D1 inside
  ctx.waitUntil so the redirect never waits, then 302s with X-Robots-Tag:
  noindex and Cache-Control: no-store.
- Inject UTM params at redirect time from the link's KV record, and pass
  incoming fbclid, gclid, gbraid, wbraid, and msclkid through to the
  destination untouched.
- Log per click: slug, timestamp, country from request.cf, user-agent,
  referer, and those ad click ids. Skip bot user-agents from a pattern list
  in one file.
- An /admin page behind one password (wrangler secret) to create links and
  show clicks per link per day as a plain table.
- Secrets via wrangler secret, never in wrangler.toml. No accounts, no
  third-party analytics, no telemetry.
- Out of scope: posting Purchase events back to Meta CAPI or Google offline
  conversion import · stable event_id for pixel dedup, fbc as
  fb.1.{timestamp_ms}.{fbclid}, and refund reversal. A silently wrong
  conversion feed is worse than none.
- Out of scope: TLS for domains I do not own. My own subdomain is one DNS
  record · a client's domain means Cloudflare for SaaS and DCV renewals.
- README: wrangler setup, the KV namespace and D1 database, the DNS record,
  and adding the first link.

## Required capabilities

- Cloudflare account (Workers, KV, D1)
- a domain you control
- wrangler CLI

## Delivery order

1. Scaffold the smallest runnable application and document its commands.
2. Implement the primary data model and core workflow.
3. Add validation, safe failure states, and persistence.
4. Cover the critical path with automated tests.
5. Exercise a clean install from the README and fix every missing step.

## Done when

- A new user can go from clone to first successful workflow using only the README.
- The core workflow works without paid infrastructure unless the brief requires it.
- Tests cover the highest-risk behavior.
- Known limitations are explicit rather than hidden.

===== .env.example =====
# Copy to .env and document every variable when it is introduced.
# Never put real credentials in this file.

APP_ENV=development
# Add only values required by the selected implementation.

You are building a lean indie version of LnkFlow.

Create the following project files first, then implement the application by following them. Keep the files updated as decisions change. Do not collapse this into a single README or prompt.

===== README.md =====
# LnkFlow indie build

## Goal

Build the smallest trustworthy replacement for the core LnkFlow workflow for one developer or a tiny team.

## Scope

Resolve a slug to a destination at the edge, log the click, inject UTMs, pass ad click ids through untouched, and 302.

## Quick start

1. Install the documented dependencies.
2. Copy `.env.example` to `.env`.
3. Run the development command chosen during implementation.
4. Complete the acceptance checks in `BUILD_PLAN.md`.

## Honest limits

This build deliberately does not replace:
- Purchase events delivered back to Meta CAPI with stable event_id deduplication against the browser pixel
- Google offline conversion import keyed on gclid, gbraid, or wbraid
- click to lead to sale attribution that survives a multi-day gap, with refund reversal
- TLS on a customer's branded domain (Cloudflare for SaaS and 90-day DCV renewals, not one DNS record)
- per-creator performance and commission reporting

If those capabilities are essential, use Dub instead of pretending the gap is solved.

===== AGENTS.md =====
# Agent instructions

- Optimize for a working, understandable weekend build.
- Prefer the fewest moving parts that satisfy the brief.
- Do not invent cryptography, security guarantees, APIs, or compliance claims.
- Keep secrets out of source control and logs.
- Add focused tests for destructive, security-sensitive, and data-loss paths.
- Run the project checks before declaring the build complete.
- Record any deliberate shortcut in the README under "Tradeoffs".

===== BUILD_PLAN.md =====
# Build plan

## Original build brief

Build me a branded link shortener with click tracking to replace LnkFlow. Requirements:

- Cloudflare Workers via wrangler: KV for the slug lookup, D1 for the click
  log. Free tier, nothing to babysit.
- A worker on lnk.mydomain.com/{slug} reads KV, writes the click to D1 inside
  ctx.waitUntil so the redirect never waits, then 302s with X-Robots-Tag:
  noindex and Cache-Control: no-store.
- Inject UTM params at redirect time from the link's KV record, and pass
  incoming fbclid, gclid, gbraid, wbraid, and msclkid through to the
  destination untouched.
- Log per click: slug, timestamp, country from request.cf, user-agent,
  referer, and those ad click ids. Skip bot user-agents from a pattern list
  in one file.
- An /admin page behind one password (wrangler secret) to create links and
  show clicks per link per day as a plain table.
- Secrets via wrangler secret, never in wrangler.toml. No accounts, no
  third-party analytics, no telemetry.
- Out of scope: posting Purchase events back to Meta CAPI or Google offline
  conversion import · stable event_id for pixel dedup, fbc as
  fb.1.{timestamp_ms}.{fbclid}, and refund reversal. A silently wrong
  conversion feed is worse than none.
- Out of scope: TLS for domains I do not own. My own subdomain is one DNS
  record · a client's domain means Cloudflare for SaaS and DCV renewals.
- README: wrangler setup, the KV namespace and D1 database, the DNS record,
  and adding the first link.

## Required capabilities

- Cloudflare account (Workers, KV, D1)
- a domain you control
- wrangler CLI

## Delivery order

1. Scaffold the smallest runnable application and document its commands.
2. Implement the primary data model and core workflow.
3. Add validation, safe failure states, and persistence.
4. Cover the critical path with automated tests.
5. Exercise a clean install from the README and fix every missing step.

## Done when

- A new user can go from clone to first successful workflow using only the README.
- The core workflow works without paid infrastructure unless the brief requires it.
- Tests cover the highest-risk behavior.
- Known limitations are explicit rather than hidden.

===== .env.example =====
# Copy to .env and document every variable when it is introduced.
# Never put real credentials in this file.

APP_ENV=development
# Add only values required by the selected implementation.

You are building a production product version of LnkFlow.

Create the following project files first, then implement the application by following them. Keep the files updated as decisions change. Do not collapse this into a single README or prompt.

===== PRODUCT.md =====
# LnkFlow product brief

## Problem

A short link that 302s, logs the click, and injects UTMs is genuinely one sitting on Cloudflare Workers and KV, and the prompt below builds exactly that. What is not one sitting is the loop back out to the ad platforms. Meta and Google bid against the conversion events you send them, and since ATT the browser pixel misses a large share of purchases, which is the entire reason the Conversions API and offline conversion import exist. Closing that loop means persisting fbclid and gclid at redirect time, carrying that identity to a sale that happens days later on another device, posting a Purchase with a stable event_id so it deduplicates against the pixel, rebuilding fbc in Meta's fb.1.{timestamp}.{fbclid} form, importing offline conversions to Google on gclid, gbraid, or wbraid, and reversing all of it on refund. Every one of those fails silently. That is the expensive part: the dashboard still shows clicks while the bidder optimizes against nothing.

## Product outcome

Resolve a slug to a destination at the edge, log the click, inject UTMs, pass ad click ids through untouched, and 302.

## Target user

A serious builder who needs a maintainable product foundation rather than a one-off demo.

## Required capabilities

- Cloudflare account (Workers, KV, D1)
- a domain you control
- wrangler CLI

## Explicit non-goals for v1

- Purchase events delivered back to Meta CAPI with stable event_id deduplication against the browser pixel
- Google offline conversion import keyed on gclid, gbraid, or wbraid
- click to lead to sale attribution that survives a multi-day gap, with refund reversal
- TLS on a customer's branded domain (Cloudflare for SaaS and 90-day DCV renewals, not one DNS record)
- per-creator performance and commission reporting

## Success criteria

- The primary workflow is measurable end to end.
- Setup is reproducible in a clean environment.
- Failure, recovery, and support paths are documented.
- Product claims match what the implementation actually guarantees.

===== ARCHITECTURE.md =====
# Architecture

## Starting brief

Build me a branded link shortener with click tracking to replace LnkFlow. Requirements:

- Cloudflare Workers via wrangler: KV for the slug lookup, D1 for the click
  log. Free tier, nothing to babysit.
- A worker on lnk.mydomain.com/{slug} reads KV, writes the click to D1 inside
  ctx.waitUntil so the redirect never waits, then 302s with X-Robots-Tag:
  noindex and Cache-Control: no-store.
- Inject UTM params at redirect time from the link's KV record, and pass
  incoming fbclid, gclid, gbraid, wbraid, and msclkid through to the
  destination untouched.
- Log per click: slug, timestamp, country from request.cf, user-agent,
  referer, and those ad click ids. Skip bot user-agents from a pattern list
  in one file.
- An /admin page behind one password (wrangler secret) to create links and
  show clicks per link per day as a plain table.
- Secrets via wrangler secret, never in wrangler.toml. No accounts, no
  third-party analytics, no telemetry.
- Out of scope: posting Purchase events back to Meta CAPI or Google offline
  conversion import · stable event_id for pixel dedup, fbc as
  fb.1.{timestamp_ms}.{fbclid}, and refund reversal. A silently wrong
  conversion feed is worse than none.
- Out of scope: TLS for domains I do not own. My own subdomain is one DNS
  record · a client's domain means Cloudflare for SaaS and DCV renewals.
- README: wrangler setup, the KV namespace and D1 database, the DNS record,
  and adding the first link.

## Boundaries

Separate the product into replaceable modules for interface, application logic, persistence, external integrations, and operational concerns. Keep domain logic independent from delivery frameworks and vendors.

## Production baseline

- Configuration: validated at startup with safe local defaults where possible.
- Security: least privilege, input validation, secret redaction, rate limits on abuse-prone paths, and no invented security primitives.
- Data: explicit schema and migrations, transactional writes where integrity matters, backup and restore instructions.
- Integrations: adapters around third-party providers, idempotent webhook or job processing, bounded retries, and timeouts.
- Observability: structured logs with request or operation IDs, an error-tracking hook, and health/readiness checks where a server exists.
- Quality: unit tests for domain rules, integration tests at module boundaries, and one end-to-end critical-path test.

## Decision records

For each major dependency, document why it was chosen, its failure mode, and how it can be replaced. Do not introduce infrastructure until a requirement justifies it.

===== AGENTS.md =====
# Agent instructions

- Read `PRODUCT.md` and `ARCHITECTURE.md` before changing code.
- Implement milestone by milestone; keep each change reviewable and leave the application runnable.
- Treat authentication, payments, encryption, imports, webhooks, and destructive actions as high-risk boundaries when present.
- Never invent cryptography or silently weaken a requirement to make a test pass.
- Use provider interfaces for external services and deterministic fakes in tests.
- Add migrations and rollback or recovery notes for persistent data changes.
- Log useful operational context without credentials, tokens, passwords, or personal data.
- Update documentation and run all checks before completing a milestone.

===== MILESTONES.md =====
# Delivery milestones

## M0 — Decisions and scaffold

- Confirm the runtime, persistence model, threat boundaries, and deployment target.
- Create a reproducible local environment and continuous checks.

## M1 — Core workflow

- Implement the smallest end-to-end product path with validation and tests.
- Keep integrations behind interfaces.

## M2 — Trust layer

- Add secure failure behavior, recovery paths, audit-relevant events, and data safeguards.
- Test abuse cases and destructive operations.

## M3 — Operability

- Add structured logs, error reporting hooks, health signals, backup/restore documentation, and deployment configuration.

## M4 — Release gate

- Run a clean-install test, critical-path end-to-end test, dependency review, and documented rollback exercise.
- Compare the shipped behavior with `PRODUCT.md` and publish remaining limitations.

===== OPERATIONS.md =====
# Operations

## Before release

- Validate configuration and secrets at startup.
- Define backup, restore, and rollback procedures and test them.
- Document logs, error tracking, health signals, and alert ownership.
- Set dependency update and vulnerability review expectations.

## Incident checklist

1. Contain the issue without destroying evidence or user data.
2. Record the timeline and affected scope.
3. Rotate exposed secrets and revoke compromised sessions or credentials.
4. Restore from a verified source when needed.
5. Document the root cause, remediation, and regression test.

## Launch constraint

Do not market omitted LnkFlow capabilities as implemented. The v1 non-goals in `PRODUCT.md` remain user-visible limitations until they are deliberately delivered.

# LnkFlow indie build

## Goal

Build the smallest trustworthy replacement for the core LnkFlow workflow for one developer or a tiny team.

## Scope

Resolve a slug to a destination at the edge, log the click, inject UTMs, pass ad click ids through untouched, and 302.

## Quick start

1. Install the documented dependencies.
2. Copy `.env.example` to `.env`.
3. Run the development command chosen during implementation.
4. Complete the acceptance checks in `BUILD_PLAN.md`.

## Honest limits

This build deliberately does not replace:
- Purchase events delivered back to Meta CAPI with stable event_id deduplication against the browser pixel
- Google offline conversion import keyed on gclid, gbraid, or wbraid
- click to lead to sale attribution that survives a multi-day gap, with refund reversal
- TLS on a customer's branded domain (Cloudflare for SaaS and 90-day DCV renewals, not one DNS record)
- per-creator performance and commission reporting

If those capabilities are essential, use Dub instead of pretending the gap is solved.

# Agent instructions

- Optimize for a working, understandable weekend build.
- Prefer the fewest moving parts that satisfy the brief.
- Do not invent cryptography, security guarantees, APIs, or compliance claims.
- Keep secrets out of source control and logs.
- Add focused tests for destructive, security-sensitive, and data-loss paths.
- Run the project checks before declaring the build complete.
- Record any deliberate shortcut in the README under "Tradeoffs".

# Build plan

## Original build brief

Build me a branded link shortener with click tracking to replace LnkFlow. Requirements:

- Cloudflare Workers via wrangler: KV for the slug lookup, D1 for the click
  log. Free tier, nothing to babysit.
- A worker on lnk.mydomain.com/{slug} reads KV, writes the click to D1 inside
  ctx.waitUntil so the redirect never waits, then 302s with X-Robots-Tag:
  noindex and Cache-Control: no-store.
- Inject UTM params at redirect time from the link's KV record, and pass
  incoming fbclid, gclid, gbraid, wbraid, and msclkid through to the
  destination untouched.
- Log per click: slug, timestamp, country from request.cf, user-agent,
  referer, and those ad click ids. Skip bot user-agents from a pattern list
  in one file.
- An /admin page behind one password (wrangler secret) to create links and
  show clicks per link per day as a plain table.
- Secrets via wrangler secret, never in wrangler.toml. No accounts, no
  third-party analytics, no telemetry.
- Out of scope: posting Purchase events back to Meta CAPI or Google offline
  conversion import · stable event_id for pixel dedup, fbc as
  fb.1.{timestamp_ms}.{fbclid}, and refund reversal. A silently wrong
  conversion feed is worse than none.
- Out of scope: TLS for domains I do not own. My own subdomain is one DNS
  record · a client's domain means Cloudflare for SaaS and DCV renewals.
- README: wrangler setup, the KV namespace and D1 database, the DNS record,
  and adding the first link.

## Required capabilities

- Cloudflare account (Workers, KV, D1)
- a domain you control
- wrangler CLI

## Delivery order

1. Scaffold the smallest runnable application and document its commands.
2. Implement the primary data model and core workflow.
3. Add validation, safe failure states, and persistence.
4. Cover the critical path with automated tests.
5. Exercise a clean install from the README and fix every missing step.

## Done when

- A new user can go from clone to first successful workflow using only the README.
- The core workflow works without paid infrastructure unless the brief requires it.
- Tests cover the highest-risk behavior.
- Known limitations are explicit rather than hidden.

# Copy to .env and document every variable when it is introduced.
# Never put real credentials in this file.

APP_ENV=development
# Add only values required by the selected implementation.

# LnkFlow product brief

## Problem

A short link that 302s, logs the click, and injects UTMs is genuinely one sitting on Cloudflare Workers and KV, and the prompt below builds exactly that. What is not one sitting is the loop back out to the ad platforms. Meta and Google bid against the conversion events you send them, and since ATT the browser pixel misses a large share of purchases, which is the entire reason the Conversions API and offline conversion import exist. Closing that loop means persisting fbclid and gclid at redirect time, carrying that identity to a sale that happens days later on another device, posting a Purchase with a stable event_id so it deduplicates against the pixel, rebuilding fbc in Meta's fb.1.{timestamp}.{fbclid} form, importing offline conversions to Google on gclid, gbraid, or wbraid, and reversing all of it on refund. Every one of those fails silently. That is the expensive part: the dashboard still shows clicks while the bidder optimizes against nothing.

## Product outcome

Resolve a slug to a destination at the edge, log the click, inject UTMs, pass ad click ids through untouched, and 302.

## Target user

A serious builder who needs a maintainable product foundation rather than a one-off demo.

## Required capabilities

- Cloudflare account (Workers, KV, D1)
- a domain you control
- wrangler CLI

## Explicit non-goals for v1

- Purchase events delivered back to Meta CAPI with stable event_id deduplication against the browser pixel
- Google offline conversion import keyed on gclid, gbraid, or wbraid
- click to lead to sale attribution that survives a multi-day gap, with refund reversal
- TLS on a customer's branded domain (Cloudflare for SaaS and 90-day DCV renewals, not one DNS record)
- per-creator performance and commission reporting

## Success criteria

- The primary workflow is measurable end to end.
- Setup is reproducible in a clean environment.
- Failure, recovery, and support paths are documented.
- Product claims match what the implementation actually guarantees.

# Architecture

## Starting brief

Build me a branded link shortener with click tracking to replace LnkFlow. Requirements:

- Cloudflare Workers via wrangler: KV for the slug lookup, D1 for the click
  log. Free tier, nothing to babysit.
- A worker on lnk.mydomain.com/{slug} reads KV, writes the click to D1 inside
  ctx.waitUntil so the redirect never waits, then 302s with X-Robots-Tag:
  noindex and Cache-Control: no-store.
- Inject UTM params at redirect time from the link's KV record, and pass
  incoming fbclid, gclid, gbraid, wbraid, and msclkid through to the
  destination untouched.
- Log per click: slug, timestamp, country from request.cf, user-agent,
  referer, and those ad click ids. Skip bot user-agents from a pattern list
  in one file.
- An /admin page behind one password (wrangler secret) to create links and
  show clicks per link per day as a plain table.
- Secrets via wrangler secret, never in wrangler.toml. No accounts, no
  third-party analytics, no telemetry.
- Out of scope: posting Purchase events back to Meta CAPI or Google offline
  conversion import · stable event_id for pixel dedup, fbc as
  fb.1.{timestamp_ms}.{fbclid}, and refund reversal. A silently wrong
  conversion feed is worse than none.
- Out of scope: TLS for domains I do not own. My own subdomain is one DNS
  record · a client's domain means Cloudflare for SaaS and DCV renewals.
- README: wrangler setup, the KV namespace and D1 database, the DNS record,
  and adding the first link.

## Boundaries

Separate the product into replaceable modules for interface, application logic, persistence, external integrations, and operational concerns. Keep domain logic independent from delivery frameworks and vendors.

## Production baseline

- Configuration: validated at startup with safe local defaults where possible.
- Security: least privilege, input validation, secret redaction, rate limits on abuse-prone paths, and no invented security primitives.
- Data: explicit schema and migrations, transactional writes where integrity matters, backup and restore instructions.
- Integrations: adapters around third-party providers, idempotent webhook or job processing, bounded retries, and timeouts.
- Observability: structured logs with request or operation IDs, an error-tracking hook, and health/readiness checks where a server exists.
- Quality: unit tests for domain rules, integration tests at module boundaries, and one end-to-end critical-path test.

## Decision records

For each major dependency, document why it was chosen, its failure mode, and how it can be replaced. Do not introduce infrastructure until a requirement justifies it.

# Agent instructions

- Read `PRODUCT.md` and `ARCHITECTURE.md` before changing code.
- Implement milestone by milestone; keep each change reviewable and leave the application runnable.
- Treat authentication, payments, encryption, imports, webhooks, and destructive actions as high-risk boundaries when present.
- Never invent cryptography or silently weaken a requirement to make a test pass.
- Use provider interfaces for external services and deterministic fakes in tests.
- Add migrations and rollback or recovery notes for persistent data changes.
- Log useful operational context without credentials, tokens, passwords, or personal data.
- Update documentation and run all checks before completing a milestone.

# Delivery milestones

## M0 — Decisions and scaffold

- Confirm the runtime, persistence model, threat boundaries, and deployment target.
- Create a reproducible local environment and continuous checks.

## M1 — Core workflow

- Implement the smallest end-to-end product path with validation and tests.
- Keep integrations behind interfaces.

## M2 — Trust layer

- Add secure failure behavior, recovery paths, audit-relevant events, and data safeguards.
- Test abuse cases and destructive operations.

## M3 — Operability

- Add structured logs, error reporting hooks, health signals, backup/restore documentation, and deployment configuration.

## M4 — Release gate

- Run a clean-install test, critical-path end-to-end test, dependency review, and documented rollback exercise.
- Compare the shipped behavior with `PRODUCT.md` and publish remaining limitations.

# Operations

## Before release

- Validate configuration and secrets at startup.
- Define backup, restore, and rollback procedures and test them.
- Document logs, error tracking, health signals, and alert ownership.
- Set dependency update and vulnerability review expectations.

## Incident checklist

1. Contain the issue without destroying evidence or user data.
2. Record the timeline and affected scope.
3. Rotate exposed secrets and revoke compromised sessions or credentials.
4. Restore from a verified source when needed.
5. Document the root cause, remediation, and regression test.

## Launch constraint

Do not market omitted LnkFlow capabilities as implemented. The v1 non-goals in `PRODUCT.md` remain user-visible limitations until they are deliberately delivered.

$ choose a build depth, inspect the files, then open the complete pack in your agent