Butterbase is an open-source backend-as-a-service that gives applications managed building blocks such as Postgres data, authentication, file storage, serverless functions, an AI gateway, and an MCP server. It is for developers building AI-driven applications and backend services. The catalogue add-ons operate or integrate with Butterbase through its agent-oriented interfaces.
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.
npx agentmods add instructions/butterbase-ai/butterbase/agents-mdgit clone --depth 1 https://github.com/butterbase-ai/butterbaseWrote 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.
[](https://agentmods.dev/instructions/butterbase-ai/butterbase/agents-md)<a href="https://agentmods.dev/instructions/butterbase-ai/butterbase/agents-md"><img src="https://agentmods.dev/badge/instructions/butterbase-ai/butterbase/agents-md.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00299 | $0.00299 |
| Opus 5 | $0.00150 | $0.00150 |
| Sonnet 5 | $0.00060 | $0.00060 |
| Haiku 4.5 | $0.00030 | $0.00030 |
Grade A, and why
butterbase AGENTS.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 5d 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.
What it actually says
Agent notes (Butterbase)
File storage
When implementing uploads or media in apps on Butterbase:
- After upload, persist
objectId(UUID) from the API/SDK response—not theobjectKey(bucket path). The key is not a URL and will not work asimg srcorhref. - To show images or offer downloads, call
getDownloadUrl(objectId)(SDK) orGET /storage/{app_id}/download/{object_id}/ MCPgenerate_download_urland use the returned presigned URL until it expires. - Resolve download URLs when loading UI (or API responses), not once at insert time only—presigned URLs expire;
objectIdis the stable reference. - For lists with many files, resolve presigned URLs in parallel (e.g.
Promise.all). - Deployment issues (wrong host on presigned URLs, browser CORS on PUT): see DEPLOYMENT_PLAN.md §2.5 Cloudflare R2 (
S3_PUBLIC_ENDPOINT, R2 CORS).
Full product documentation: MCP butterbase_docs with topic storage, source services/mcp-server/src/docs/user-documentation.ts (SECTIONS.storage).
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.
- 5d ago First seen · 14 lines · 299 tokens per session scan A 431fc7e8ee75
butterbase AGENTS.md is an instructions file published in the GitHub repository butterbase-ai/butterbase (3,416 stars, last pushed yesterday), licensed Apache-2.0. It adds 299 tokens to every session, about $0.0015 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.
Other instructions, from other repositories
skillsboard AGENTS.md
AGENTS.md instructions for TommyBez/skillsboard, covering agents.md, cursor cloud specific instructions, what this is, running locally and database schema.
appwrite AGENTS.md
AGENTS.md instructions for appwrite/appwrite, covering appwrite, commands, stack, layout and libraries.
openscreen AGENTS.md
AGENTS.md instructions for getopenscreen/openscreen, covering agents.md, setup commands, development principles, project layout and code style.
Claw3D AGENTS.md
Instructions for iamlukethedev/Claw3D, covering agent instructions, cursor cloud specific instructions, service overview, running the app and lint, typecheck, and tests.
openstatus CLAUDE.md
Claude Code instructions for openstatusHQ/openstatus, covering claude.md and investigating production with polylane.
abap2UI5 CLAUDE.md
Claude Code instructions for abap2UI5/abap2UI5: All project guidance lives in AGENTS.md — the single source of truth for this repository (architecture and the layered design, the src/00-99 packages, the generated app/webapp mirror, the build and delivery pipeline, the CI gates and ABAP code style).