How it works
One URL and a coding agent is signed in to your Firebase app. The full technical description of firebase-agent-sandbox — what it does, what it is made of, and what state it is in.
The premise
Coding agents cannot sign in to Firebase applications. Sign-up needs an inbox, a password or an OAuth consent screen, so agents only ever see logged-out pages and cannot verify the features they change. Throwaway test accounts pollute the user list, skew analytics and leak state between runs.
This library fixes that for sites you operate. Import it once and an agent can open a single URL and land in a signed-in, sandboxed session under a stable test identity with freshly seeded fixture data. Data is wiped between runs; the identity is permanent.
What is included
Stable named personas — an agent returns to the same identity every run
Fixture data seeded per session and wiped afterwards, so runs never leak state
Parallel lanes so several agents can work against one project at once
MCP server and CLI for grant creation, with a service-key-guarded grant endpoint
How it is built
firebase-agent-sandbox is built on TypeScript, Firebase and MCP.
The repository is 96% TypeScript, 4% JavaScript by volume — a description of what the work actually consists of rather than what it is filed under.
It carries 7 commits since Aug 2026, most recently changed in Aug 2026.
The method behind it
Every project here starts as a written specification, and the specification stays authoritative once code exists. The repository keeps a build plan with live status, an append-only decision log recording where the implementation departed from the plan, and a handoff document describing the true current state — including the parts that are not finished.
That is why a portfolio this wide is not a shallow one, and it is why this page can describe the product without overstating it.
Current state
Prototype. Working, not yet finished.
The source is private. What this page claims is checkable against the product itself, not the repository.
Next
Put firebase-agent-sandbox in your pipeline
Ask about integrating it with the repositories and agents you already run.