feat(rss): add RSS feed reader with auto-discovery

- Add rss articles/get/info commands
- Auto-discover feed URL from blog home page
- Support common feed paths and HTML link tag discovery
- No profile storage needed - one-shot operations

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: pal-hexrays

bun.lock

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+# RSS Feed Integration Analysis
+
+**Date:** January 2026
+**Status:** HIGHLY RECOMMENDED
+
+## Executive Summary
+
+RSS (Really Simple Syndication) integration is an excellent fit for agentio. Unlike social media APIs, RSS feeds are:
+- **Public** - No authentication required
+- **Standardized** - Well-defined XML formats (RSS 2.0, Atom, RDF)
+- **Free** - No API costs or rate limits
+- **Read-only** - Focused on content consumption
+
+This makes RSS one of the simplest integrations to implement while providing high value for LLM agents that need to consume web content.
+
+## API Overview
+
+### Feed Formats Supported
+
+| Format | Description | Common Use |
+|--------|-------------|------------|
+| RSS 2.0 | Most common, XML-based | Blogs, news sites |
+| Atom | More modern, XML-based | Google services, modern blogs |
+| RDF | Older format | Legacy feeds |
+| JSON Feed | Modern JSON-based | Developer blogs |
+
+### No Authentication Required
+
+RSS feeds are designed for public consumption. The "profile" concept in agentio would store:
+- Feed URL
+- Optional display name
+- Optional category/tag
+
+No OAuth, API keys, or tokens needed.
+
+## Capabilities for agentio
+
+### Read Operations
+
+| Operation | Description | Implementation |
+|-----------|-------------|----------------|
+| `list` | List articles from a feed | Fetch and parse feed XML |
+| `get` | Get full article content | Fetch feed, find by ID/GUID |
+| `search` | Search across saved feeds | Parse multiple feeds, filter |
+
+### Profile Management
+
+Instead of credentials, profiles store feed configurations:
+
+```typescript
+interface RssProfile {
+  url: string;           // Feed URL
+  name?: string;         // Display name
+  category?: string;     // Optional grouping
+  lastFetched?: number;  // Cache timestamp
+}
+```
+
+### Proposed Commands
+
+```bash
+# Feed management
+agentio rss add <url> [--name <name>] [--profile <name>]
+agentio rss list                           # List configured feeds
+agentio rss remove --profile <name>
+
+# Article operations
+agentio rss articles [--profile <name>] [--limit N] [--since <date>]
+agentio rss get <article-id> [--profile <name>]
+agentio rss search --query <text> [--profile <name>]
+
+# Multi-feed operations
+agentio rss all [--limit N]                # Articles from all feeds
+```
+
+## Technical Implementation
+
+### Recommended Library: rss-parser
+
+[rss-parser](https://www.npmjs.com/package/rss-parser) is the most popular choice:
+- 2M+ weekly downloads
+- TypeScript support built-in
+- Handles RSS 2.0, Atom, and RDF
+- Works with custom fields
+- Promise-based API
+
+```typescript
+import Parser from 'rss-parser';
+
+const parser = new Parser();
+const feed = await parser.parseURL('https://example.com/feed.xml');
+
+console.log(feed.title);
+for (const item of feed.items) {
+  console.log(item.title, item.link, item.pubDate);
+}
+```
+
+### Alternative: Feedsmith
+
+[Feedsmith](https://github.com/macieklamberski/feedsmith) is a newer option:
+- TypeScript-first
+- Supports JSON Feed format
+- OPML import/export
+- Tree-shakable
+
+### No External Dependencies Option
+
+Could also use native fetch + a lightweight XML parser, but rss-parser handles edge cases and malformed feeds gracefully.
+
+## Architecture Differences from Other Services
+
+| Aspect | Other Services | RSS |
+|--------|----------------|-----|
+| Authentication | OAuth/API keys | None |
+| Credentials storage | Encrypted tokens | Plain feed URLs |
+| Profile = | Account access | Feed subscription |
+| Rate limits | Platform-imposed | None (be polite) |
+| Write operations | Yes | No (read-only) |
+
+### Profile Storage
+
+Since no secrets are involved, RSS profiles could be stored in plain config:
+
+```json
+{
+  "profiles": {
+    "rss": ["tech-news", "dev-blog", "company-updates"]
+  },
+  "rss": {
+    "tech-news": {
+      "url": "https://news.ycombinator.com/rss",
+      "name": "Hacker News"
+    },
+    "dev-blog": {
+      "url": "https://blog.example.com/feed.xml",
+      "name": "Dev Blog"
+    }
+  }
+}
+```
+
+## Rate Limiting Considerations
+
+While RSS has no official rate limits, best practices:
+- Cache feeds locally (refresh every 15-30 min)
+- Respect `ttl` element if present in feed
+- Use conditional GET (If-Modified-Since header)
+- Don't hammer feeds on every command
+
+## Feasibility Assessment
+
+### Pros
+
+1. **No authentication** - Simplest integration possible
+2. **No API costs** - Completely free
+3. **No rate limits** - Within reason
+4. **Standardized format** - Well-supported libraries
+5. **High value** - LLM agents can consume news, blogs, updates
+6. **Offline-friendly** - Can cache feeds locally
+
+### Cons / Limitations
+
+1. **Read-only** - Cannot post to RSS feeds
+2. **Full content varies** - Some feeds only include summaries
+3. **No real-time** - Polling-based, not push
+4. **Inconsistent quality** - Some feeds are malformed
+
+### Risk Matrix
+
+| Risk | Severity | Likelihood | Mitigation |
+|------|----------|------------|------------|
+| Malformed feed | Low | Medium | rss-parser handles gracefully |
+| Feed URL changes | Low | Low | User re-adds feed |
+| CORS issues | N/A | N/A | CLI tool, not browser |
+| Feed removed | Low | Low | Clear error message |
+
+## Recommendation: IMPLEMENT
+
+**Priority: HIGH** - This should be one of the easiest and most valuable integrations.
+
+### Implementation Estimate
+
+| Phase | Effort |
+|-------|--------|
+| Types | 15 min |
+| Client | 30 min |
+| Commands | 45 min |
+| Output | 20 min |
+| Testing | 30 min |
+| **Total** | **~2.5 hours** |
+
+### Comparison with Other Services
+
+| Service | Auth Complexity | Implementation Time | Value |
+|---------|-----------------|---------------------|-------|
+| RSS | None | 2.5 hours | High |
+| Discord | Low (token) | 3 hours | High |
+| Confluence | Medium (OAuth) | 16-20 hours | Medium |
+| Twitter | High (OAuth + $) | 8-12 hours | Medium |
+
+## Sources
+
+- [rss-parser - npm](https://www.npmjs.com/package/rss-parser)
+- [Feedsmith - GitHub](https://github.com/macieklamberski/feedsmith)
+- [@rowanmanning/feed-parser](https://github.com/rowanmanning/feed-parser)
+- [Building an RSS Feed Reader with TypeScript](https://www.timsanteford.com/posts/building-an-rss-feed-reader-with-typescript-and-axios/)