Mem
Capture notes quickly and retrieve them through semantic search and related-memory suggestions
The core loop is buildable, but a dependable replacement becomes a real weekend or multi-day project. For Mem, capture notes quickly and retrieve them through semantic search and related-memory suggestions. The hard boundary is hosted ai memory, sync, ingest integrations, and continuously tuned retrieval, plus sync, collaboration, and capture polish.
Build verification: not recorded. How we judge buildability
What you give up
- hosted AI memory, sync, ingest integrations, and continuously tuned retrieval
- frictionless mobile capture
- real-time team editing
- hosted publishing
- proprietary AI memory
Why people still pay
People still pay for Mem because people keep paying when the note system is trusted across every device and disappears into their daily capture habits. The recurring cost buys file watching, conflict handling, indexing, mobile apps, encryption, backups, and migrations, not just the visible interface.
Your build guide
The stack, security requirements, and agent rules for a focused replacement.
Before you start
- Node and the Rust toolchain, a supported desktop build environment and an explicitly selected data folder. Remote sync is outside the initial scope.
- Implementation components: Tauri, React and TypeScript for the desktop interface with a narrowly scoped Rust filesystem bridge. SQLite for structured state and search; user-owned files for original documents and attachments.
- Scope boundary: hosted AI memory, sync, ingest integrations, and continuously tuned retrieval; frictionless mobile capture
Use these project rules and optional skill references alongside the prompt. Review each skill before adding it to your agent; the AGENTS.md export includes the same guidance.
Optional external skill: vercel-react-best-practices — Improve React and Next.js data fetching, rendering, bundle size and server performance. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: web-design-guidelines — Review web interfaces for accessibility, keyboard focus, forms, navigation and interaction quality. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: sharp-edges — Review security-sensitive APIs and configuration for dangerous defaults and easy-to-misuse interfaces. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Project rule — data model: notes, immutable note IDs, links, derived embeddings, source revisions and suggestion feedback
Project rule — preserve this invariant: Embeddings are keyed by content hash and model; semantic similarity is not a factual relationship and cannot silently create links.
Project rule — acceptance evidence: Edit a note and exclude its stale embedding until rebuilt; renaming the note preserves backlinks and a clean export contains original Markdown.
Implementation plan
Phase 1
Scope and fixtures. Implement this bounded workflow: Capture notes quickly, search text and optionally local embeddings, and show related notes with an explanation of the matching passages. Keep Markdown files portable and suggestions separate from authored content. Record prerequisites, select representative user-owned fixtures and document the unsupported features: hosted AI memory, sync, ingest integrations, and continuously tuned retrieval; frictionless mobile capture
Phase 2
Durable model. Model notes, immutable note IDs, links, derived embeddings, source revisions and suggestion feedback Add migrations or a versioned document format, explicit validation, stable IDs and a visible import-error report. Preserve this rule: Embeddings are keyed by content hash and model; semantic similarity is not a factual relationship and cannot silently create links.
Phase 3
Complete the first useful path. Implement the workflow's input, review and output interface, with clear controls and explicit empty/error states. Save edits atomically with stable IDs and revision history. Detect external file changes and offer a conflict copy instead of last-write-wins data loss.
Phase 4
Permissions and integration failure. Limit Tauri capabilities to selected folders and commands. Render imported content without executable HTML, and never expose arbitrary shell execution to the webview. Request integration credentials and permissions only for the enabled feature; show a disconnected state instead of mock results.
Phase 5
Portable handoff. Provide a portable folder export with a JSON manifest and original files. Restore to a separate folder; rebuild disposable indexes from sources. Include setup, operating limits, fixture walkthrough and shutdown/restart instructions in the README.
Phase 6
Acceptance scenarios. Edit a note and exclude its stale embedding until rebuilt; renaming the note preserves backlinks and a clean export contains original Markdown. Repeat the workflow after restart and with a denied permission or unavailable dependency; show recoverable failure rather than a success placeholder.
WORKING SLICE Capture notes quickly, search text and optionally local embeddings, and show related notes with an explanation of the matching passages. Keep Markdown files portable and suggestions separate from authored content. Build this scoped Mem-inspired workflow with a documented data model and visible failure states. Architecture - Tauri, React and TypeScript for the desktop interface with a narrowly scoped Rust filesystem bridge. - SQLite for structured state and search; user-owned files for original documents and attachments. Prerequisites and limits Node and the Rust toolchain, a supported desktop build environment and an explicitly selected data folder. Remote sync is outside the initial scope. Outside this release: hosted AI memory, sync, ingest integrations, and continuously tuned retrieval; frictionless mobile capture Data model and correctness notes, immutable note IDs, links, derived embeddings, source revisions and suggestion feedback Invariant: Embeddings are keyed by content hash and model; semantic similarity is not a factual relationship and cannot silently create links. Save edits atomically with stable IDs and revision history. Detect external file changes and offer a conflict copy instead of last-write-wins data loss. Security and privacy Limit Tauri capabilities to selected folders and commands. Render imported content without executable HTML, and never expose arbitrary shell execution to the webview. Recovery and export Provide a portable folder export with a JSON manifest and original files. Restore to a separate folder; rebuild disposable indexes from sources. Implementation order 1. Phase 1 — Scope and fixtures. Implement this bounded workflow: Capture notes quickly, search text and optionally local embeddings, and show related notes with an explanation of the matching passages. Keep Markdown files portable and suggestions separate from authored content. Record prerequisites, select representative user-owned fixtures and document the unsupported features: hosted AI memory, sync, ingest integrations, and continuously tuned retrieval; frictionless mobile capture 2. Phase 2 — Durable model. Model notes, immutable note IDs, links, derived embeddings, source revisions and suggestion feedback Add migrations or a versioned document format, explicit validation, stable IDs and a visible import-error report. Preserve this rule: Embeddings are keyed by content hash and model; semantic similarity is not a factual relationship and cannot silently create links. 3. Phase 3 — Complete the first useful path. Implement the workflow's input, review and output interface, with clear controls and explicit empty/error states. Save edits atomically with stable IDs and revision history. Detect external file changes and offer a conflict copy instead of last-write-wins data loss. 4. Phase 4 — Permissions and integration failure. Limit Tauri capabilities to selected folders and commands. Render imported content without executable HTML, and never expose arbitrary shell execution to the webview. Request integration credentials and permissions only for the enabled feature; show a disconnected state instead of mock results. 5. Phase 5 — Portable handoff. Provide a portable folder export with a JSON manifest and original files. Restore to a separate folder; rebuild disposable indexes from sources. Include setup, operating limits, fixture walkthrough and shutdown/restart instructions in the README. 6. Phase 6 — Acceptance scenarios. Edit a note and exclude its stale embedding until rebuilt; renaming the note preserves backlinks and a clean export contains original Markdown. Repeat the workflow after restart and with a denied permission or unavailable dependency; show recoverable failure rather than a success placeholder. Acceptance Edit a note and exclude its stale embedding until rebuilt; renaming the note preserves backlinks and a clean export contains original Markdown. Use real source data or clearly labeled fixtures. Explain unsupported input and provider failures; do not fabricate analytics, delivery receipts, accuracy claims or security guarantees. Optional agent guidance Optional external skill: [vercel-react-best-practices](https://github.com/vercel-labs/agent-skills/blob/main/skills/react-best-practices/SKILL.md) — Improve React and Next.js data fetching, rendering, bundle size and server performance. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission. Optional external skill: [web-design-guidelines](https://github.com/vercel-labs/agent-skills/blob/main/skills/web-design-guidelines/SKILL.md) — Review web interfaces for accessibility, keyboard focus, forms, navigation and interaction quality. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission. Optional external skill: [sharp-edges](https://github.com/trailofbits/skills/blob/main/plugins/sharp-edges/skills/sharp-edges/SKILL.md) — Review security-sensitive APIs and configuration for dangerous defaults and easy-to-misuse interfaces. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission. Project rule — data model: notes, immutable note IDs, links, derived embeddings, source revisions and suggestion feedback Project rule — preserve this invariant: Embeddings are keyed by content hash and model; semantic similarity is not a factual relationship and cannot silently create links. Project rule — acceptance evidence: Edit a note and exclude its stale embedding until rebuilt; renaming the note preserves backlinks and a clean export contains original Markdown.
$ open in your agent (prompt prefilled, you press enter), copy the prompt or copy or download AGENTS.md
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Questions about Mem
Can you build your own Mem with AI?
Partly. The core loop is buildable, but a dependable replacement becomes a real weekend or multi-day project. For Mem, capture notes quickly and retrieve them through semantic search and related-memory suggestions. The hard boundary is hosted ai memory, sync, ingest integrations, and continuously tuned retrieval, plus sync, collaboration, and capture polish.
What does the Mem build prompt cover?
The prompt starts with this scope: Capture notes quickly, search text and optionally local embeddings, and show related notes with an explanation of the matching passages. Keep Markdown files portable and suggestions separate from authored content. Full-product capabilities excluded from the comparison include: hosted AI memory, sync, ingest integrations, and continuously tuned retrieval; frictionless mobile capture; real-time team editing. Follow the implementation plan and its prerequisites before expanding the build.
How do I use the prompt, AGENTS.md and agent skills?
Start with the Mem prerequisites and stack, then copy the prompt into your coding agent. Save the project rules as AGENTS.md in the project root. Linked skills are optional packages or source instructions for specific tasks; review their current contents and install only those matching the chosen stack. A skill does not supply API credentials or verify the finished app.
How long will this Mem project take?
The catalogue estimate is one sitting for the limited scope. Setup, integration approvals, debugging, deployment and ongoing maintenance can add time. This is an estimate, not a delivery guarantee.
What would I give up by replacing Mem?
hosted AI memory, sync, ingest integrations, and continuously tuned retrieval; frictionless mobile capture; real-time team editing; hosted publishing; proprietary AI memory. People still pay for Mem because people keep paying when the note system is trusted across every device and disappears into their daily capture habits. The recurring cost buys file watching, conflict handling, indexing, mobile apps, encryption, backups, and migrations, not just the visible interface.
What price is this guide comparing against?
The recorded Mem plan is $14.99/mo (monthly), checked 2026-07-31. Check the linked pricing source before buying. Building your own also has hosting, API and maintenance costs; the recorded amount is not a guaranteed saving.
What can I use instead of building Mem?
Atomic: A second brain that actually connects notes for you; bring your own model and mind the newness. Check each option's license, hosting needs and feature limits.