Why not just use print() or logging?

Logging shows fragments. Tether connects the prompt, action, file diff, command output, failed test, and recovery point in one local execution graph.

Can I use this with production code?

Yes. It's a local proxy, so your real code doesn't change. Use it locally for debugging, or keep it running. Tether only stores traces locally and never sends anything anywhere.

How much money does caching actually save?

It depends on your agent. If you're iterating on prompt logic and re-running the same retrieval steps, caching saves you 50-90% of API spend while you debug. Each cached hit costs $0.0000.

Does Tether add latency to my agent?

Negligible. Tether runs locally on your machine. The only overhead is the proxy hop, which is less than 1ms. Real LLM calls are the bottleneck, not Tether.

Can I share traces with my team?

Not yet. Each developer runs their own Tether instance locally. Export as JSON is coming in a later release.

How does Tether intercept LLM calls without SDK changes?

Tether runs a local HTTP proxy on your machine. You point your AI client's base_url at http://localhost:8080/v1 — that's the only change required. Tether forwards requests to the real provider and records everything locally.

Does Tether send my prompts or API keys to the cloud?

No. Tether is fully air-gapped. Your prompts and responses stay on your machine. macOS secrets use Keychain-aware storage, Linux uses the same local proxy model, and traces stay local.

Which LLM providers does Tether support?

Tether supports OpenAI, Anthropic, Ollama, LM Studio, and any provider that accepts an OpenAI-compatible base_url. It also works with LangChain, LangGraph, LlamaIndex, and similar frameworks.

Yes. Tether is free during the alpha period. The core proxy is open source.

Home/Docs/Connect CometAPI

Getting Started

Connect CometAPI

Save a CometAPI key in the local proxy and use recovery replay from the macOS inspector.

Install Setup steps

Release: Alpha channel
Runtime: macOS + Linux + local proxy
Docs: 19 guides

What CometAPI enables

Tether can replay a captured trace node through CometAPI with a different model. The original request stays in the local trace store, the proxy sends the replay to CometAPI, and the inspector shows a side-by-side diff of the original and replayed response.

Compare a failed or surprising response against another model without rebuilding the whole agent run.
Review latency, token, and cost differences in the replay diff sheet.
Keep the CometAPI key in the local proxy settings database instead of hard-coding it in scripts.

Save and test the key

Open the desktop app and go to Settings -> Extensions.
In the CometAPI section, paste your CometAPI API key.
Click Save & Test.
A successful connection shows Connected with the number of available models.

The Save & Test action stores the key through the local proxy endpoint PUT /api/settings/cometapi-key, then fetches the model list from CometAPI. You do not need to add the key to Keychain for this workflow.

Run cross-model replay

Run an agent call through the Tether proxy so a node appears in the graph.
Click the node and open the inspector footer.
Use the Cross-model replay picker to choose a CometAPI model.
Click Replay with selected model to open the ReplayDiffView sheet.

Troubleshooting

Symptom	Check
Save & Test returns an error	Confirm the local proxy is running and the CometAPI key is valid.
No models appear	Retry Save & Test; the model picker depends on GET /api/providers/cometapi/models.
Replay button fails	Confirm the selected trace node has a stored request body that can be replayed.