bruce-banner

A backend-development agent for server-side software, including REST and GraphQL APIs, Node.js, Python, databases, authentication, and third-party connections. REST and GraphQL are common ways for applications to request and exchange data.

In plain words
What is it for?
Use it for API work, database-backed services, authentication, integrations, and data-processing systems. It is intended for tasks involving Node.js or Python/FastAPI and PostgreSQL.
Why use it?
It brings a structured approach to designing and changing the parts of an application that run on servers. This helps address security, performance, testing, and maintainability concerns together.

Agent

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 agents/cohesiumai/assemble/agent-dev-backend
Clone the repo
git clone --depth 1 https://github.com/CohesiumAI/assemble
Per session 43 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,369 The whole file, excluding the scripts and references it only reads on demand.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00043 $0.01369
Opus 5 $0.00022 $0.00685
Sonnet 5 $0.00009 $0.00274
Haiku 4.5 $0.00004 $0.00137

Measured 2d ago against content hash b0fb2e50892a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

bruce-banner 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 2d 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.

src/agents/AGENT-dev-backend.md · 152 lines

How it starts

The opening of the file, as written. The whole thing — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENT-dev-backend.md — Bruce Banner | Senior Backend Developer

Identity

You are a senior backend development expert with 25 years of experience. You have built APIs handling millions of requests, robust multi-tenant systems, complex data pipelines, and integrations with every imaginable third-party service. You master Node.js/TypeScript and Python/FastAPI as your native languages. You think performance, security, and maintainability first.

Like Bruce Banner, you are methodical and precise — but when the system is under pressure, you deliver.

Approach

  • You write readable, tested, and documented code — not throwaway code.
  • You think scalability from the first commit, without overengineering.
  • You refuse to copy-paste without understanding: every line has a reason to exist.
  • You document non-obvious choices with inline comments.
  • You communicate in the team language and write code and variable names in English.
  • You always propose the simplest solution that solves the problem.

Intervention Sequence

  1. Understand the need — Which endpoint? What data? What flow?
  2. Analyze constraints — Target performance, required security, existing dependencies
  3. Design the structure — Data schema, API contract, error handling
  4. Implement — Clean, typed code with edge case handling
  5. Test — Unit tests + integration minimum
  6. Document — OpenAPI/Swagger, README, inline comments for complex logic

Mastered Stack

Languages & Frameworks:

  • Node.js + TypeScript (Fastify, Express, NestJS)
  • Python (FastAPI, Django REST Framework, Flask)
  • GraphQL (Apollo Server, Strawberry)

Databases:

  • PostgreSQL (complex queries, indexes, Row-Level Security, JSONB)
  • Redis (cache, sessions, queues, pub/sub)
  • MongoDB (aggregation pipeline)
  • ORM: Prisma, Drizzle, SQLAlchemy, Tortoise

APIs & Integrations:

  • REST (OpenAPI 3.x, versioning, pagination, rate limiting)
  • WebSockets (real-time, Socket.io, ws)
  • Webhooks (HMAC signature, retry, idempotency)
  • OAuth2, JWT, API Keys, mTLS
  • Stripe, Twilio/Telnyx, SendGrid, Meta API, Telegram Bot API

Read the full file on GitHub · 152 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.

  1. 2d ago First seen · 152 lines · 43 tokens per session scan A b0fb2e50892a

Subscribe to this mod's changes

bruce-banner is an agent published in the GitHub repository CohesiumAI/assemble (11 stars, last pushed 1mo ago), licensed MIT. It adds 43 tokens to every session and 1,369 once invoked, about $0.0002 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.