What is upjack CLAUDE.md?

Repository instructions for Upjack, a framework for building AI-native applications packaged as MCPB files. They describe its Python and TypeScript libraries, schemas, skills, examples, and relationship and activity features.

Use them to develop Upjack applications, validate their package data, work with entity relationships, record activities, and follow the repository's directory structure.

They give agents a map of the framework so they can find the right library, schema, or example when working on an app. They also explain how applications navigate related data and track activity.

How NimbleBrainInc/upjack configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to NimbleBrainInc/upjack. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/NimbleBrainInc/upjack/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/NimbleBrainInc/upjack

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

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Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

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Per session 2,010 This file is loaded in full into every session.

When invoked 2,010 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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 5.1	$0.02010	$0.02010
Opus 5.5	$0.00804	$0.00804
Sonnet 5.5	$0.00402	$0.00402
Haiku 4.5	$0.00201	$0.00201

Measured 2mo ago against content hash b6c2b027f946, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

upjack CLAUDE.md 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 2mo 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.

CLAUDE.md · 179 lines

How it starts

The opening of the file, as written. The whole thing — 179 lines — stays where its author put it; the contents beside it link to each section on GitHub.

NimbleBrain Upjack Framework

Declarative AI-native application framework. Apps are MCPB packages with a _meta["ai.nimblebrain/upjack"] extension.

Current version: 0.1.0 Package names: upjack on PyPI, upjack on npm

Directory Layout

lib/python/       Python library (upjack) — source in src/upjack/
lib/typescript/   TypeScript library (upjack) — source in src/
schemas/          JSON Schemas (upjack-entity, upjack-manifest) + validation tooling
skills/           Publishable skills (upjack-app-builder) — symlinked from .claude/skills/
examples/         Reference apps (CRM, Todo, Research Assistant)
website/          Documentation site (Astro/Starlight) — upjack.dev
workspace/        Runtime entity data (gitignored, created at runtime)

Key Modules (Python)

Module	Purpose
`upjack.relations`	Write-time reverse relationship index — `query_reverse()`, `rebuild_index()`
`upjack.activity`	Activity entity tracking — `log_activity()`, `get_activities()`

Graph Traversal (UpjackApp)

Methods for navigating entity relationships:

query_by_relationship(entity_type, rel, target_id, filter?, limit?) — reverse index lookup (e.g., find all deals linked to a contact)
get_related(entity_id, rel?, direction?) — follow edges forward or reverse, returns resolved entities
get_composite(entity_type, entity_id, depth?) — load entity + all related in one call; _related key contains forward (rel) and reverse (~rel) edges

CRUD hooks: on_relationships_changed callback fires on create_entity, update_entity, delete_entity — UpjackApp auto-wires this to maintain the reverse index.

Activity Tracking

Opt-in via "activities": true in manifest _meta["ai.nimblebrain/upjack"] extension.

log_activity(subject_id, action, detail?) — creates an activity entity with a subject relationship
get_activities(subject_id, action?, limit?) — reverse index query for a subject's activities
Activity schema: action (string, required), detail (object, optional)

Read the full file on GitHub · 179 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.

2mo ago First seen · 179 lines · 2,010 tokens per session scan A b6c2b027f946

Subscribe to this mod's changes

upjack CLAUDE.md is an instructions file published in the GitHub repository NimbleBrainInc/upjack (11 stars, last pushed 6mo ago), licensed Apache-2.0. It adds 2,010 tokens to every session, about $0.0080 per session on Opus 5.5. 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.

ai ai-agents ai-native cli declarative framework

upjack CLAUDE.md next to 6 instructions from other repositories
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upjack: Instructions file for Claude Code