HMRSAFE
Real hot-module reload for Python—side effects handled reactively. https://py3.online/hmr
Overview
From the repository's own README, as read at the audited commit. Badges and raw HTML are left out.
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HMR provides a pythonic, flexible, progressive-yet-intuitive reactive programming engine / framework, and on top of that, a fine-grained, on-demand hot-reload tool.
In Python, HMR stands for Hot Module Reload, though in JavaScript it commonly refers to [Hot Module Replacement][webpack-concepts-docs]—essentially the same concept. It is a feature that allows part of your app to be updated at runtime without a full rerun, without needing to restart the entire process. [](https://pyth-on-line.promplate.dev/hmr/llms.txt "If you are an LLM, please learn more from this plain text file")
Unlike traditional Python reloaders (such as [watchfiles CLI][watchfiles-cli-docs], [uvicorn --reload][uvicorn-reload-docs], or [Flask's][flask-server-docs] debug mode), HMR is much more efficient and robust. These tools typically restart the entire process whenever a file changes, which is wasteful. HMR instead intelligently reruns only what's necessary, keeping your app state intact.
https://github.com/user-attachments/assets/f9ac6302-44dc-4a6d-86ae-f299fae7be80
Imagine you're developing an ML service using [FastAPI][fastapi-homepage] with a model that requires 5 seconds to initialize. When using uvicorn --reload, any change—even updating a simple docstring—triggers a full process restart, forcing you to wait those 5 seconds every time. It's as frustrating as encountering a red light at every intersection.
HMR offers a smoother experience. Changes take effect instantly because HMR is variable-level fine-grained: your codebase functions like a dependency graph—when you modify a file, HMR only rer
c0a2a0bc2addOBSERVED · 2026-10-07Connect
Built from this server's own package name, version and transport as found in its source — not copied from anyone's documentation, so it cannot drift against a page we do not control.
claude mcp add hmr-cookbook -- uvx hmr-cookbook
{
"mcpServers": {
"hmr-cookbook": {
"command": "uvx",
"args": [
"hmr-cookbook"
]
}
}
}Exposed tools (1)
1 read · 0 write · 0 destructive.
| Tool | Risk | Description |
|---|---|---|
echo | read | return message |
Trust audit
SAFEgrade B · trust 89/100 Nothing in the source contradicts what it says it does. Grade A is reserved for packages that have also passed the behavioural sandbox.
| Layer | What it checks | Result |
|---|---|---|
| L0 | Provenance & inventory | PASS |
| L1 | Static analysis of the code | PASS |
| L2 | Instruction surface (what it tells the agent) | PASS |
| L3 | Class-specific surface | PASS |
| L4 | Behavioural (sandbox) | SKIPPED |
What the source does
- Filesystem
- none-observed
- Network
- declared (2 observation(s))
- Shell
- none-observed
- Dependencies
- pinned
- Secrets in source
- none-found
Findings (2)
> Internally, `mcp-hmr` temporarily patches `ServerSession.__init__` during FastMCP session initialization and restores it as soon as the managed session is captured. The Python MCP SDK does not expos
Gates applied: no_behavioural_pass, no_license.
c0a2a0bc2addfull audit observations/trust-audit/mcp-server/promplate__hmr.json · Report an issue / request a re-scanAudit history
Every audit this server has had. A grade with a past is a grade somebody is still checking.
| Date | Source | Verdict | Grade | Score | Change |
|---|---|---|---|---|---|
| 2026-10-07 | c0a2a0bc2add | SAFE | B | 89 | first audit |
Questions
What is the HMR MCP server?
Real hot-module reload for Python—side effects handled reactively. https://py3.online/hmr
What tools does HMR expose?
1 in total: 1 read-only, 0 that write, and 0 that can delete or overwrite. Every one is listed on this page with its risk.
Is HMR safe to connect to an agent?
The audit found nothing in the source that contradicts what it says it does, and graded it B (89/100). Grade A is held back for packages that have also passed a sandboxed behavioural run, which is why a clean server reads B.
What credentials does HMR need?
No credential environment variables were found in its source, so it appears to need none.
How does HMR run?
It speaks sse, stdio and streamable-http, so it runs as a local process your client starts. It is published on PyPI as hmr-cookbook.
How current is this page?
The grade is for one exact copy of the source (c0a2a0bc2add), read on 2026-10-07. The repository is watched and re-audited when it changes.