source-driven-development

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• Correctness does not depend on a specific version (renaming variables, fixing typos, moving files)

• Pure logic that works the same across all versions (loops, conditionals, data structures)

• The user explicitly wants speed over verification ("just do it quickly")

The Process

DETECT ──→ FETCH ──→ IMPLEMENT ──→ CITE

  │          │           │            │

  ▼          ▼           ▼            ▼

 What       Get the    Follow the   Show your

 stack?     relevant   documented   sources

            docs       patterns

Step 1: Detect Stack and Versions

Read the project's dependency file to identify exact versions:

package.json    → Node/React/Vue/Angular/Svelte

composer.json   → PHP/Symfony/Laravel

requirements.txt / pyproject.toml → Python/Django/Flask

go.mod          → Go

Cargo.toml      → Rust

Gemfile         → Ruby/Rails

State what you found explicitly:

STACK DETECTED:

- React 19.1.0 (from package.json)

- Vite 6.2.0

- Tailwind CSS 4.0.3

→ Fetching official docs for the relevant patterns.

If versions are missing or ambiguous, ask the user. Don't guess — the version determines which patterns are correct.

Step 2: Fetch Official Documentation

Fetch the specific documentation page for the feature you're implementing. Not the homepage, not the full docs — the relevant page.

Source hierarchy (in order of authority):

Priority

Source

Example

1

Official documentation

react.dev, docs.djangoproject.com, symfony.com/doc

2

Official blog / changelog

react.dev/blog, nextjs.org/blog

3

Web standards references

MDN, web.dev, html.spec.whatwg.org

4

Browser/runtime compatibility

caniuse.com, node.green

Not authoritative — never cite as primary sources:

• Stack Overflow answers

• Blog posts or tutorials (even popular ones)

• AI-generated documentation or summaries

• Your own training data (that is the whole point — verify it)

Be precise with what you fetch:

BAD:  Fetch the React homepage

GOOD: Fetch react.dev/reference/react/useActionState

BAD:  Search "django authentication best practices"

GOOD: Fetch docs.djangoproject.com/en/6.0/topics/auth/

After fetching, extract the key patterns and note any deprecation warnings or migration guidance.

When official sources conflict with each other (e.g. a migration guide contradicts the API reference), surface the discrepancy to the user and verify which pattern actually works against the detected version.

Step 3: Implement Following Documented Patterns

Write code that matches what the documentation shows:

• Use the API signatures from the docs, not from memory

• If the docs show a new way to do something, use the new way

• If the docs deprecate a pattern, don't use the deprecated version

• If the docs don't cover something, flag it as unverified

When docs conflict with existing project code:

CONFLICT DETECTED:

The existing codebase uses useState for form loading state,

but React 19 docs recommend useActionState for this pattern.

(Source: react.dev/reference/react/useActionState)

Options:

A) Use the modern pattern (useActionState) — consistent with current docs

B) Match existing code (useState) — consistent with codebase

→ Which approach do you prefer?

Surface the conflict. Don't silently pick one.

Step 4: Cite Your Sources

Every framework-specific pattern gets a citation. The user must be able to verify every decision.

In code comments:

// React 19 form handling with useActionState

// Source: https://react.dev/reference/react/useActionState#usage

const [state, formAction, isPending] = useActionState(submitOrder, initialState);

In conversation:

I'm using useActionState instead of manual useState for the

form submission state. React 19 replaced the manual

isPending/setIsPending pattern with this hook.

Source: https://react.dev/blog/2024/12/05/react-19#actions

"useTransition now supports async functions [...] to handle

pending states automatically"

Citation rules:

• Full URLs, not shortened

• Prefer deep links with anchors where possible (e.g. /useActionState#usage over /useActionState) — anchors survive doc restructuring better than top-level pages

• Quote the relevant passage when it supports a non-obvious decision

• Include browser/runtime support data when recommending platform features

• If you cannot find documentation for a pattern, say so explicitly:

UNVERIFIED: I could not find official documentation for this

pattern. This is based on training data and may be outdated.

Verify before using in production.

Honesty about what you couldn't verify is more valuable than false confidence.

Common Rationalizations

Rationalization

Reality

"I'm confident about this API"

Confidence is not evidence. Training data contains outdated patterns that look correct but break against current versions. Verify.

"Fetching docs wastes tokens"

Hallucinating an API wastes more. The user debugs for an hour, then discovers the function signature changed. One fetch prevents hours of rework.

"The docs won't have what I need"

If the docs don't cover it, that's valuable information — the pattern may not be officially recommended.

"I'll just mention it might be outdated"

A disclaimer doesn't help. Either verify and cite, or clearly flag it as unverified. Hedging is the worst option.

"This is a simple task, no need to check"

Simple tasks with wrong patterns become templates. The user copies your deprecated form handler into ten components before discovering the modern approach exists.

Red Flags

• Writing framework-specific code without checking the docs for that version

• Using "I believe" or "I think" about an API instead of citing the source

• Implementing a pattern without knowing which version it applies to

• Citing Stack Overflow or blog posts instead of official documentation

• Using deprecated APIs because they appear in training data

• Not reading package.json / dependency files before implementing

• Delivering code without source citations for framework-specific decisions

• Fetching an entire docs site when only one page is relevant

Verification

After implementing with source-driven development:

• Framework and library versions were identified from the dependency file

• Official documentation was fetched for framework-specific patterns

• All sources are official documentation, not blog posts or training data

• Code follows the patterns shown in the current version's documentation

• Non-trivial decisions include source citations with full URLs

• No deprecated APIs are used (checked against migration guides)

• Conflicts between docs and existing code were surfaced to the user

• Anything that could not be verified is explicitly flagged as unverified