Add Perplexity LLM plugin

[jliounis]

Summary

Adds a livekit-plugins-perplexity plugin that exposes Perplexity's OpenAI-compatible chat completions endpoint as a LiveKit Agents LLM.

The plugin is a thin wrapper around livekit-plugins-openai, mirroring the pattern used by livekit-plugins-cerebras and livekit-plugins-baseten:

• base_url = https://api.perplexity.ai
• Default model: sonar-pro
• API key from the PERPLEXITY_API_KEY env var (or argument)
• Reuses the existing OpenAI plugin transport — no new runtime dependencies

from livekit.plugins import perplexity

llm = perplexity.LLM(model="sonar-pro")  # picks up PERPLEXITY_API_KEY

Attribution header

Every outgoing chat request carries X-Pplx-Integration: livekit-agents/<plugin-version> (forwarded via extra_headers on the underlying OpenAI client) so usage from the LiveKit integration can be attributed upstream. A unit test asserts this header is configured.

Test plan

• uv run --package livekit-plugins-perplexity pytest tests/test_plugin_perplexity.py — 4 passed
• uv run ruff check livekit-plugins/livekit-plugins-perplexity tests/test_plugin_perplexity.py — clean
• Plugin imports and LLM() instantiates with PERPLEXITY_API_KEY set; raises a clear ValueError otherwise
• LLM().provider == "Perplexity" and _client.base_url starts with https://api.perplexity.ai

The added tests are pure mocks (no network) and cover: default model, base URL, attribution header, missing-key error, and provider name.

Files

• livekit-plugins/livekit-plugins-perplexity/ — new package (mirrors cerebras/baseten layout)
• tests/test_plugin_perplexity.py — unit tests
• pyproject.toml — register new workspace member

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[devin-ai-integration]

Devin Review found 1 potential issue.

⚠️ 1 issue in files not directly in the diff

⚠️ Missing perplexity optional dependency in livekit-agents/pyproject.toml (livekit-agents/pyproject.toml:102)

Every other standalone plugin package (cerebras, xai, openai, anthropic, etc.) is registered as an optional dependency in livekit-agents/pyproject.toml:59-124 so users can install via pip install livekit-agents[perplexity]. The PR adds the workspace source in the root pyproject.toml:45 but omits the corresponding perplexity = ["livekit-plugins-perplexity>=1.5.6"] entry in livekit-agents/pyproject.toml. For reference, the cerebras plugin added its entry (cerebras = ["livekit-plugins-cerebras>=1.5.6"] at livekit-agents/pyproject.toml:77) when it was first introduced in its PR.

View 3 additional findings in Devin Review.

[tinalenguyen]

Hi @james-pplx, thank you for creating this PR! Could you sign the CLA and add the plugin to livekit-agents/pyproject.toml?

[tinalenguyen]

Suggested change

	See [https://docs.livekit.io/agents/integrations/llm/](https://docs.livekit.io/agents/integrations/llm/) for more information.
	See [https://docs.livekit.io/agents/models/llm/perplexity/](https://docs.livekit.io/agents/models/llm/perplexity/) for more information.

we can update the docs on our end to reflect this plugin