Issue for this PR

Closes #

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Adds a ### Perplexity section to packages/web/src/content/docs/providers.mdx (between ### OpenRouter and ### LLM Gateway) so opencode users can wire up Perplexity without reverse-engineering it.

It documents two integration paths:

1. Agent API — Perplexity's Agent API is OpenAI Responses-compatible (/v1/responses aliases /v1/agent), so the example uses @ai-sdk/openai. This matches the guidance already in opencode's "Custom provider" section ("If your provider/model uses /v1/responses, use @ai-sdk/openai"). The opencode.json snippet is shaped exactly like the surrounding custom-provider examples (llama.cpp / LM Studio): provider id, npm, name, options.baseURL, options.apiKey via {env:PERPLEXITY_API_KEY}, and a models map. The example lists routed third-party models (openai/gpt-5.4, anthropic/claude-sonnet-4-6) to demonstrate the Agent API's main differentiator — multi-provider routing. The full model list is linked.
2. Search API — shown two ways:
   • Direct HTTP via curl against https://api.perplexity.ai/search for scripts and one-off calls.
   • Via MCP using the official Perplexity MCP server (@perplexity-ai/mcp-server) configured as a type: "local" stdio MCP in opencode. The schema (type, command, environment) matches packages/web/src/content/docs/mcp-servers.mdx exactly.

Why it works:

• The @ai-sdk/openai package handles /v1/responses providers and is already the recommended package for that case in this same docs file, so no AI SDK / opencode code changes are needed.
• The mcp.<id> block uses the documented local-stdio schema; nothing is invented.
• The MCP command (npx -y @perplexity-ai/mcp-server) is the canonical install command from the official MCP server README.
• All external links resolve to canonical Perplexity docs pages (Agent API quickstart / models / OpenAI compatibility / presets / reference; Search API quickstart / reference; API key dashboard) or the official MCP server repository.

This is documentation-only — no runtime code, schema, or build pipeline is touched.

How did you verify your code works?

• bun run lint from the repo root — 0 errors (pre-existing warnings only, none in providers.mdx).
• bun --cwd packages/web run build — Astro build completes successfully; the new section renders correctly in dist/docs/providers/index.html with anchor #perplexity, every link intact, and zero Sonar references in the output.
• Manually inspected the rendered HTML to confirm heading levels, code fences, and link anchors match the surrounding OpenRouter / LLM Gateway sections.
• The 148 errors astro check reports on .tsx / .astro files are pre-existing on dev (confirmed by stashing this change and re-running) and unrelated to this PR.

Screenshots / recordings

N/A — text-only docs change. The new section renders in the existing providers page layout with no UI changes.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

Note: only the English packages/web/src/content/docs/providers.mdx is updated. Locale translations under packages/web/src/content/docs/<locale>/providers.mdx should be regenerated by maintainers using the project's translation workflow.