# AGENTS.md — Build guide for Feedbin ## Project scope Import an OPML library, read articles in folders, save favorites and optionally route newsletters from one explicitly configured inbound address into the same reader. Catalogue verdict: yes. Feedbin's solo core is compact: build a private RSS reader workspace that imports user-supplied URLs or files, extracts metadata, supports notes, and searches the local corpus. A competent builder can reach a useful personal version in one sitting, while the paid product mainly wins on data, import reliability. Use the implementation prompt below to define the deliverable. Complete each phase's acceptance checks before extending the scope. ## Working agreement - Inspect the repository and its existing instructions before choosing paths, dependencies or commands. Keep one coherent stack and explain changes to the proposed architecture. - Plan a vertical slice that accepts a real input and produces the useful output described below. Persist only the state the prompt calls for; respect memory-only and upstream-managed workflows. Use fixtures only when they are clearly labelled. - After scaffolding, document the actual install, development, check and build commands in README and keep them synchronized with the package or project manifest. Do not report commands as successful unless they ran. - Work in small steps. At handoff, list implemented flows, checks actually performed, remaining blockers, and any credentials or provider setup the owner must supply. - Do not publish, spend money, contact customers, delete source data or run irreversible migrations without the project owner's authorization. ## Prerequisites - Runtime and tools: Python, a bounded HTTP worker, feedparser, SQLite FTS5 and a small local web reader. - Before starting: A reviewed list of permitted RSS/Atom feeds and OPML examples; a running worker is required for scheduled refresh. ## Stack and architecture - Python, a bounded HTTP worker, feedparser, SQLite FTS5 and a small local web reader - Data design: Store Feed, FeedItem, Subscription, ReadState and NewsletterMessageID; read state belongs to a stable item and duplicate mail deliveries cannot create duplicate articles. - Setup: A reviewed list of permitted RSS/Atom feeds and OPML examples; a running worker is required for scheduled refresh ## Security and data integrity - Preserve feed GUIDs with a canonical URL fallback. Use conditional requests, per-host backoff and separate fetch errors from empty feeds; sanitize article HTML and prevent private-network URL fetches. - Start with RSS before inbound email. The inbound address needs abuse limits and a provider/parser setup; full-text fetching applies only where permitted and cannot guarantee paywall access. - Keep secrets outside client bundles and exported projects; document what leaves the device and make retention/deletion controls visible. ## Agent implementation rules - Project rule — domain: Store Feed, FeedItem, Subscription, ReadState and NewsletterMessageID; read state belongs to a stable item and duplicate mail deliveries cannot create duplicate articles. - Project rule — scope and recovery: Start with RSS before inbound email. The inbound address needs abuse limits and a provider/parser setup; full-text fetching applies only where permitted and cannot guarantee paywall access. - Project rule — acceptance: Import OPML twice, replay a newsletter message and update a feed article body; subscriptions stay unique, read state survives and the content revision remains inspectable. - Project rule — delivery: document real setup commands and permissions; do not claim a build, accuracy level, performance result or security certification that has not been demonstrated. ## Optional agent skills and references - Recommended skill: [modern-python](https://github.com/trailofbits/skills/blob/main/plugins/modern-python/skills/modern-python/SKILL.md) — structure the Python worker or explicitly optional read-only utility with pinned dependencies, typed boundaries and clear failure handling. Follow the maintainer's installation instructions and match its requirements to the chosen runtime. - Recommended skill: [web-design-guidelines](https://github.com/vercel-labs/agent-skills/blob/main/skills/web-design-guidelines/SKILL.md) — review keyboard access, focus, validation, error recovery and the readable work/review interface or HTML report. Follow the maintainer's installation instructions and match its requirements to the chosen runtime. Read the linked SKILL.md and its dependencies before adding a skill. Select only the skills matching this project's runtime and task; their documentation does not supply API access, credentials or approval to perform external actions. Pin the reviewed revision where the tool supports it. Follow the chosen agent's documented project-level installation mechanism. ## Distribution ideas These are optional planning notes. Obtain the owner's approval before publishing or contacting anyone. - Demonstrate this working slice using synthetic or explicitly authorized non-sensitive examples: Import an OPML library, read articles in folders, save favorites and optionally route newsletters from one explicitly configured inbound address into the same reader. - Share a synthetic example export and the acceptance walkthrough; keep real customer, health, financial and source data private: Import OPML twice, replay a newsletter message and update a feed article body; subscriptions stay unique, read state survives and the content revision remains inspectable. - State the limits before asking someone to replace their existing tool: Start with RSS before inbound email. The inbound address needs abuse limits and a provider/parser setup; full-text fetching applies only where permitted and cannot guarantee paywall access. ## Engineering roadmap 1. Phase 1 — Pin the working slice and create its example input: Import an OPML library, read articles in folders, save favorites and optionally route newsletters from one explicitly configured inbound address into the same reader. Confirm setup: A reviewed list of permitted RSS/Atom feeds and OPML examples; a running worker is required for scheduled refresh. 2. Phase 2 — Implement persistence and write-time invariants before decorating the UI: Store Feed, FeedItem, Subscription, ReadState and NewsletterMessageID; read state belongs to a stable item and duplicate mail deliveries cannot create duplicate articles. 3. Phase 3 — Connect the working view to real saved state. Preserve feed GUIDs with a canonical URL fallback. Use conditional requests, per-host backoff and separate fetch errors from empty feeds; sanitize article HTML and prevent private-network URL fetches. 4. Phase 4 — Expose the app-specific limits and recovery path in context: Start with RSS before inbound email. The inbound address needs abuse limits and a provider/parser setup; full-text fetching applies only where permitted and cannot guarantee paywall access. 5. Phase 5 — Walk through this concrete acceptance case and preserve its exported evidence: Import OPML twice, replay a newsletter message and update a feed article body; subscriptions stay unique, read state survives and the content revision remains inspectable. Finish the README and backup/restore instructions; report unfinished capabilities explicitly. ## Paid-product capabilities outside this build - publisher-specific import reliability - citation graph scale - team libraries and institutional access - resilient polling of malformed and rate-limited feeds - licensed scholarly metadata ## Implementation prompt Build the following focused alternative to Feedbin. Implement the focused workflow below first; the verdict is not evidence of a completed or production-certified build. WORKING SLICE Import an OPML library, read articles in folders, save favorites and optionally route newsletters from one explicitly configured inbound address into the same reader. SETUP AND ARCHITECTURE Use Python, a bounded HTTP worker, feedparser, SQLite FTS5 and a small local web reader. Prerequisites: A reviewed list of permitted RSS/Atom feeds and OPML examples; a running worker is required for scheduled refresh. Before integrating anything, record actual versions and permissions, plus model files or provider limits only where used, in the README; make unavailable dependencies visible rather than simulating success. DOMAIN MODEL AND INVARIANTS Store Feed, FeedItem, Subscription, ReadState and NewsletterMessageID; read state belongs to a stable item and duplicate mail deliveries cannot create duplicate articles. IMPLEMENTATION CONTRACT Preserve feed GUIDs with a canonical URL fallback. Use conditional requests, per-host backoff and separate fetch errors from empty feeds; sanitize article HTML and prevent private-network URL fetches. Provide an input/setup view, the main work view, and a review/export view appropriate to this workflow. Preserve the last saved state if a job or save fails. Include empty, loading, permission-denied, partial and retryable-error states. Log identifiers and error categories without secret values or unnecessary private content. APP-SPECIFIC BOUNDARY AND RECOVERY Start with RSS before inbound email. The inbound address needs abuse limits and a provider/parser setup; full-text fetching applies only where permitted and cannot guarantee paywall access. ACCEPTANCE SCENARIO Import OPML twice, replay a newsletter message and update a feed article body; subscriptions stay unique, read state survives and the content revision remains inspectable. Also reopen the app after an interrupted operation, confirm the saved record/export remains inspectable, and document the recovery action. These are implementation acceptance requirements, not a claim that this guide has been tested. DELIVERY Deliver a runnable repository with migrations or project-format versioning, a non-sensitive example, environment/permission setup, the exact manual acceptance steps, and a backup/export-and-restore walkthrough. Implement the working slice before optional integrations; list any deferred paid-product capabilities honestly. Do not add capabilities outside the working slice just to resemble the original product. PROJECT RULES FOR AGENTS.md Keep the domain invariants above executable at the write boundary. Propose scope changes before adding providers or permissions. Never fabricate source evidence, publish results, identity matches or successful delivery. Preserve user originals and require an explicit confirmation for destructive changes or external publication. ## Completion evidence Demonstrate the prompt's acceptance scenarios against the scoped workflow. Include setup from a clean checkout and failure recovery. Check persistence across restart and export/restore only for the state the prompt says to store; for memory-only tools, confirm that temporary content is discarded as specified. Record actual results and remaining limitations. A detailed plan alone does not establish a working replacement.