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Tier 1 · Claude Code internals Claude Code internals · fetched 2026-07-02

claude-code-source-map

A full deobfuscated source map of the Claude Code npm bundle reconstructed from the published package's source maps - the largest single research artifact in this corpus (~160MB of mapped source). Its directory structure serves as the canonical map of Claude Code's internal modules.

View source on GitHub

Key takeaways

  • 01

    Use the directory layout as the canonical module map of the harness

  • 02

    Reconstructed from public npm source maps, not the internal repo

  • 03

    Cross-check ambiguous findings against the leeyeel sourcemap

Flows built on this research

From the archive

Verbatim excerpts mined from our local archive of this repository — the prompts, schemas, and patterns worth stealing.

Agent pattern

Cache-breaking prompt sections require a written reason

/**
 * Create a memoized system prompt section.
 * Computed once, cached until /clear or /compact.
 */
export function systemPromptSection(name, compute) {
  return { name, compute, cacheBreak: false }
}

/**
 * Create a volatile system prompt section that recomputes every turn.
 * This WILL break the prompt cache when the value changes.
 * Requires a reason explaining why cache-breaking is necessary.
 */
export function DANGEROUS_uncachedSystemPromptSection(name, compute, _reason) {
  return { name, compute, cacheBreak: true }
}

Restored Claude Code source: the API design itself enforces cache discipline - the volatile variant is prefixed DANGEROUS_ and demands a justification argument.

restored-src/src/constants/systemPromptSections.ts

Prompt

The Magic Docs auto-update prompt

Your ONLY task is to use the Edit tool to update the documentation file if there is substantial new information to add, then stop.

CRITICAL RULES FOR EDITING:
- Keep the document CURRENT with the latest state of the codebase - this is NOT a changelog or history
- Update information IN-PLACE to reflect the current state - do NOT append historical notes or track changes over time
- Remove or replace outdated information rather than adding "Previously..." or "Updated to..." notes
- Clean up or DELETE sections that are no longer relevant

DOCUMENTATION PHILOSOPHY - READ CAREFULLY:
- BE TERSE. High signal only. No filler wo…

Restored Claude Code source: the prompt that keeps living docs from becoming changelogs - in-place updates, deletion encouraged, terseness as policy.

restored-src/src/services/MagicDocs/prompts.ts

Memory

Team memory's two-step save protocol

Saving a memory is a two-step process:

Step 1 - write the memory to its own file in the chosen directory (private or team, per the type's scope guidance) using this frontmatter format: ...

Step 2 - add a pointer to that file in the same directory's MEMORY.md. Each entry should be one line, under ~150 characters: - [Title](file.md) - one-line hook. They have no frontmatter. Never write memory content directly into a MEMORY.md.

- Organize memory semantically by topic, not chronologically
- Update or remove memories that turn out to be wrong or outdated
- Do not write duplicate memories. First check if there is an existing memory you can update.

Restored Claude Code source: memory is a file per fact plus a size-bounded index of one-line pointers - the index is navigation, never storage.

restored-src/src/memdir/teamMemPrompts.ts